Winter Chassis Re-fresh

[wixer]

I'm hoping people will be able to see this thread of my winter re-fresh, as this seems the only way I can share the photo record. I started last October, mainly just cleaning the underfloor and replacing anything broken, worn or in the case of steel parts, rusty. I'm not finished yet, just waiting for a few parts to arrive from Japan and then after a coolant change, the rebuild can commence. I'll add further pics,as I progress.

Please ask any questions.



https://goo.gl/photos/zwWVhENC98rw84rb8

[goldnsx]

That's a lot of rust. Besides painting I'd put a thin coat of Gurulan PX11a (Vaseline + 10% bee wax, can be bought or mixed by oneself) on the parts that are prone to rust (except brakes of course).

[wixer]

It looks worse than it is. I think lack of use and left outside by previous owner, allowed all the steel parts to get this rusty. Surprisingly, they've all cleaned up ok. I use Vactan and POR15 paint from Frosts. Any rust treatment that's required, I then use Dinitrol.

Thanks for the tip of Gurulan PX11a, I'll look into it.

[paulc]

What did you use to clean the spare wheel holder? I have got mine out at the moment so would be a good opportunity to give it a good clean.

[wixer]

I used an assortment of wire brushes in an electric drill to clean most of the crud off. I then use wire wool, to take most of the shine off. All depends on what, if any, finish you want. I just wanted it cleaner than it was.

[mjames75]

Pretty standard rust I think on a used car of that age. Cleaned up well!

[paulc]

Cheers, nice job.

[wixer]

It seems like I can now upload pics, thanks to the forum upgrade over the weekend, so here's some updates on progress.
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Oil cooler top plate wasn't the best, so I've replaced whole unit. Changed the hoses and rear coolant pipe, as they were both showing their age and corrosion. I understand now why Kaz has said in one of his posts, this is a long and fiddly job.
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Rear engine mounting was split, which probably explained the clutch judder. Took some aligning to get the centre bolt through, the engine must have shifted slightly on it's mountings, so it was out of position. I had to loosen all the other mountings and carefully jack the gearbox end up slightly to get it aligned. I've left them all loose, ready to torque them all up, now I've found the correct sequence.
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Box of new bits awaiting fitment, mainly replacement fixings and brake caliper pistons.
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Finally some new shiny bits to go on.
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[wixer]

And one actually fitted.

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[Pride]

And one actually fitted.

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Looks good mate 👍, what make and model are they???

[wixer]

Looks good mate ��, what make and model are they???

BC Racing, BR Series, 10Kg springs front and rear. I'm very impressed with the quality of them after fitting them to 1990 Prelude last year and a mate has them on his S2K and he raves about them.

[Pride]

BC Racing, BR Series, 10Kg springs front and rear. I'm very impressed with the quality of them after fitting them to 1990 Prelude last year and a mate has them on his S2K and he raves about them.

I should have recognised them.

Good choice.👍

I had those exact make and model installed to my NA1 about 18 months ago, I initially had an occasional slight knocking noise from the left front but after a couple of months use the noise disappeared.
Also had to have them on almost maximum ride height adjustment for acceptable clearance over undulating roads but very well worth doing I must say.

I wish I'd cleaned my suspension and underbody as thourghly as yours though.👌😎

[wixer]

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Had a slight leak from drive shaft seal.
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New seal almost in.
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A mate made me a seal tool using his 3D printer and the end off a broom handle, worked a treat and I used the old seal to contact the new seal.

[wixer]

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Removed the inner boot to tap shaft back into the diff and found the grease was like suds, so re-packed it with fresh grease and filled gearbox up with MTF3.
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New bolts for oil cooler arrived from Japan this week, only took 10 days from when I ordered them, so RH rear upper arm could go back on.
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Rear BC coilers now fitted
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and anti-roll bar.
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Started to refill coolant, waiting for another 10 litres to arrive.

[wixer]

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Exhaust now modified with valves, just need to plumb the vacuum parts up.
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Test pipes made, in place of CATs.
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[wixer]

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Discs back from being re-ground.
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Car back on ground after 6 months, just waiting for my new wheels to arrive, hopefully this week, then ride height can be adjusted, before the trip to Centre Gravity for alignment. MOT on Thursday, so should be road legal at the end of the week, FINALLY !!!

[NZNick]

Which wheels (& tyres) have you selected?

[wixer]

Having some of these https://www.driftworks.com/work-wheels-emotion-t7r.html
17in front 18in rear, mainly due to the fact that Work wheels offer bespoke offsets, where most other aftermarket brands, don't.

[NSXGB]

They should look pretty good. What colour?

[wixer]

Matte Gunmetal, black centres.

[wixer]

MOT passed and car taxed.

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Trial fit of new 17in wheel.
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Centre Gravity working their magic.
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Now it's time to use it. Euro hoon planned for a months time through the Alps.

[Pride]

MOT passed and car taxed.

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Trial fit of new 17in wheel.
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Centre Gravity working their magic.

Now it's time to use it. Euro hoon planned for a months time through the Alps.

Great looking wheels, have you considered coming on the Euro NSX tour 19th May?

It's a great trip with up to 50 NSX's, you'd love it. Probably a good chance of still being able to book up as well.

http://www.nsxcb.co.uk/showthread.php?14386-NSX-Club-Europe-Tour-V-SAVE-THE-DATE-19-20-21-MAY

[wixer]

Sounds tempting but I've already organised the trip with a few mates and we leave on Monday 22nd, for a five day trip through France and Switzerland, incorporating some of the so called 'Euro Driving Roads', only one NSX in our party though and it's got to keep up with a couple of Porsches and and F-Type R .... no problem eh !!.

Maybe join you next year.

[goldnsx]

Switzerland
Where exactly? I hope you have fine weather.

[wixer]

Through France to Basel, Zurich, Liechtenstein, through the San Bernardino pass, then Airolo, Bern and back into France.

Thanks, I hope all the snows melted and the roads are fully open !

[goldnsx]

Chances are good that you won't have any snow as long as you go above 1500 m. Zürich, Basel, Liechtenstein are about 400 m. San Bernardino pass is about 2000 m, the tunnel about 1600 m. Roads have been salted recently again due to the last winter 'rebel'. I'm not going to drive my car until the salt has been washed off the roads after some rainy days.

Pay attention to speeding, +10 km/h is no big crime but >+25 km/h certainly IS. The modern cameras are so slim you'll only see them when it's too late.

[wixer]

Thanks for the tips. I'll drop you a line closer to the time and check on the roads, if that's Ok ?

Is there any pass we will need to get, to display in the windscreen, to drive through Switzerland ?

[goldnsx]

That's ok.

For the highway you need an 'Autobahnvignette', SFR 40, one per car you have to put on the windscreen. You should be able to buy them at the border.

EDIT: that's how it looks like this year. Once put it on the glass you can't remove it without destroying it. Even then it's hard to remove it (a 10 minutes job every year...). Even though some people use transparent double tape to fix and remove it to use it on another car the fine (SFR 200) will be as if you have none.

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[wixer]

Thanks, I'll get on and sort one.

[wixer]

Almost finished, wheels now fitted, fronts needed a 10mm spacer and extended studs. Front discs getting skimmed tomorrow morning, on the car.

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Car feels so much better on the new tyres, the old ones were that old, they were as hard as plastic, so hardly surprising.

[goldnsx]

The wheels look good. The rear might need 10mm more lowering.

My tires won't get older than two years, always fresh rubber. :)

[Pride]

Almost finished, wheels now fitted, fronts needed a 10mm spacer and extended studs. Front discs getting skimmed tomorrow morning, on the car.

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Car feels so much better on the new tyres, the old ones were that old, they were as hard as plastic, so hardly surprising.

Wheels look really good Wix, good choice mate.👍

Why not fit brand new rotors as apposed to skimming and if slotted or drilled they will really set your wheels off???😎

Hope soon on your list is to remove that bent manual aerial.:)

[wixer]

Didn't replace discs at this stage as there was plenty of material on them, they just needed a skim. Also, wanted to get wheels on before I look into potential bigger brakes, to know what will fit.

Strange you mention the aerial, I was thinking of swapping it for a bee sting type, off an S2000. What's the most popular swap ?

[Nick Graves]

S2000 twig fits an ovoid hole, so is a PIA.

Most aftermarket beestings will fit an NSX. My S2000 has a body washer JB-Welded in to take the DAB twig in the funny hole.

I use a DAB converter on the NSX's bumper-car pole.

[wixer]

S2000 twig fits an ovoid hole, so is a PIA.

Most aftermarket beestings will fit an NSX. My S2000 has a body washer JB-Welded in to take the DAB twig in the funny hole.

I use a DAB converter on the NSX's bumper-car pole.

Thanks Nick,

Any chance of a bit more of a laymans type of description or even pics or diagrams ? I'm assuming you mean by PIA, it's a direct fit to the NSX body ? (Parts In Assembly, is how we refer to PIA at JLR).

Cheers

[NSXGB]

Pain In Ass....I believe Nick means?

[wixer]

Pain In Ass....I believe Nick means?

Thanks Simon, like most jobs I'm attempting at the moment !

[wixer]

Thought it was about time I added some pics of this winters re-fresh work. Complete strip down of the top end of the engine to replace a knock sensor originally but decided whilst it was stripped down to replace all seals, sensors, gaskets, water hoses, thermostat and whatever else that looked dubious or is awkward to access when the engine is fully assembled. Also a thorough cleaning and check of inlet manifold. All replacement OEM parts from Amayama.

Shots of the before condition/cleanliness.

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Engine block top before, including leaves and what was in effect compost from them having rotted down.
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and the after cleaning.
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found the engine number
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and the gearbox number
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fuel injectors now away for cleaning and testing, hopefully nothing wrong with them, they looked pretty clean so do the back of the valves having looked down the cylinder heads at them. Not bad for a car that's done 180K miles.

[NSXR Spain]

what a good job, thanks for sharing it:)


I will do the same soon

[Pride]

what a good job, thanks for sharing it:)


I will do the same soon

I agree, a great job but one I would only undertake if absolutely necessary.😎

[NSXR Spain]

I agree, a great job but one I would only undertake if absolutely necessary.

I need to do it and clean all the admission well,I already have all the spare parts

My car have 120.000 kms and need a cleaning

[Pride]

I need to do it and clean all the admission well,I already have all the spare parts

My car have 120.000 kms and need a cleaning

Is your engine showing any strange symptoms to justify doing this overhaul??

I've done nearly 240,000km and as far as I can tell, touch wood, it starts, runs and performs as well as it's always done. My motto is "if it ain't broke don't fix it" just enjoy driving it.

I think unless like Wix you needed to remove all these components in order to access, in his case the knock sensor, surely it might be wiser to just leave best alone, unless of course you've either got plenty of time on your hands and/or you just love getting stuck into sympathetically and mechanically maintaining your car as a hobby.

Having said all that your car car does look exceptionally stunning so you probably do love doing that. 😁

[wixer]

I agree with Pride, "if it ain't broke, don't fix it". I wouldn't have stripped this all down just to clean it and TBH, a lot of the original parts were in excellent condition, for a 27 year old car. The only things that probably did need replacing were the coolant hoses that weren't the best and the report back on the fuel injectors said they were uneven in their spray pattern but they have now been serviced and cleaned, so this alone should make the car feel and drive better.

On the plus side, I do now have some more spare parts.

[NSXR Spain]

I agree with Pride, "if it ain't broke, don't fix it". I wouldn't have stripped this all down just to clean it and TBH, a lot of the original parts were in excellent condition, for a 27 year old car. The only things that probably did need replacing were the coolant hoses that weren't the best and the report back on the fuel injectors said they were uneven in their spray pattern but they have now been serviced and cleaned, so this alone should make the car feel and drive better.

On the plus side, I do now have some more spare parts.


Hi, I want to clean all the admission,I disassembled parts and I found a lot of oil and a lot of dirt, and I have time and the spare parts to do it.

Sometimes it does not start well, something is dirty, as lazy. I will going also check the injectors to check them.

I will tell you :)
Remi

[wixer]

Update. Injectors now cleaned & new seals fitted and re-installed.

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Fuel filter changed. More of an awkward job than it would first appear !

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Rocker cover removed and spark plugs removed.

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[The King]

Do you need all those washers when replacing the filter, or did you get extra just in case?

[wixer]

Do you need all those washers when replacing the filter, or did you get extra just in case?

Those washers are for the fuel lines on the inlet manifold. The filter kit came with it's own washers.

[wixer]

Update of some info I should've posted on a previous post, as it may be useful for others. I had my fuel injectors serviced and cleaned at Carwood, I used the Coventry branch, as it's local to me. They send to another branch to actually do the job and only generally a few days turn around.

https://www.carwood.co.uk

[NSXR Spain]

Hello everyone,

following the post of the friend Wix and for not opening a new one and as I commented in this same post, in the end I decided to clean all the admission of my NSX.

My car has 25 years old, I do not know exactly how the previous owner took care of him, but he knew that inside he was very dirty, and indeed he was very dirty.


he main access had a lot of accumulated fat and dirt, and the injectors, very dirty and rusty they needed a cleaning urgently of all parts

https://i.imgur.com/QHeG6Eb.jpg

https://i.imgur.com/DUAX0ej.jpg

https://i.imgur.com/Ayd54lt.jpg

there was so much hollin, that some holes were plugged

https://i.imgur.com/3Qle6vB.jpg

[NSXR Spain]

I will continue later with more publications and photos, I can not continue now

[goldnsx]

What kind of airfilter has been used in the past?

[NSXR Spain]

What kind of airfilter has been used in the past?

Hi Goldnsx, now and in the last 30.000 kms the original Oem filter, in the previous 90,000 km I do not know...

these are more the remains of oil and residue in the admission bucket and admission butterflies

https://i.imgur.com/95MOXSw.jpg

https://i.imgur.com/Ln8RVE1.jpg

also, very dirty one of the filters

https://i.imgur.com/KZ8J3ZG.jpg

when I started to disassemble the injectors, and first of all, just moving them, started to lose gasoline by the top of the injectors, the rubbers are damaged and in poor condition

https://i.imgur.com/ZccEOak.jpg


I am already cleaning everything, changing new joints and I have taken to clean the injectors

I will keep you informed

[goldnsx]

Ups, lucky you, the o-rings of the fuel injectors look to be the first ones. I change mine every 10 years or so. High recommended for anybody out there.

[Pride]

Those metal bits don’t look to good.

What is that you’ve picked up???

[wixer]

There's a lot more coking up in your inlet than mine. I think in this case, a wise decision to strip the parts down for a major overhaul. I'd get your injectors professionally checked out, if they're in that condition. Hopefully I'll get my cam covers back for the easter break and with a bit of luck, even get the car back up and running.

[NSXR Spain]

Those metal bits don’t look to good.

What is that you’ve picked up???

Hi Pride, there are no metal parts, it's just a lot of dirt and deposits of oil and oil clumps.

I am again assembling everything, it will be ready in a couple of days, with all the new gaskets

the injectors have cleaned them inside and also outside with ultrasound, the rust has disappeared, it seems that two of them did not work well


https://i.imgur.com/NTq5Ke2.jpg

https://i.imgur.com/bN9QiUN.jpg

When everything is ready and I will drive again, I will tell you if there has been improvement

Remi

[wixer]

Rear bank coil packs not so good, new ones ordered.

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Pipes and brackets re painted. Almost completed this years winter re-fresh, wish someone would tell the weather it's no longer winter !!
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[Senninha]

Hi Wix,

Reminds of one of my past winter refresh projects ... I took all the front compartment brackets out, prepared them and then had them all powder coated in an aluminuim finish ... very rewarding work when its all done ... oh, and keep the faith as the weather is bound to break by June ;)

regards, Paul

[wixer]

Hi Wix,

Reminds of one of my past winter refresh projects ... I took all the front compartment brackets out, prepared them and then had them all powder coated in an aluminuim finish ... very rewarding work when its all done ... oh, and keep the faith as the weather is bound to break by June ;)

regards, Paul

Hi Paul,

Yes, that's another one of the jobs on the list, although I did buy two new radiator top mounts amongst all the parts I needed to do the engine re-fresh and I had to remove the radiator to replace the top drain tap, that had snapped off last year.

Cheers

[wixer]

Cam covers & Plenum cover back from having a nice new coat of crackle finish applied.

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Really pleased with the finish. Had them done here,

http://www.redditchshotblasting.co.uk/contact/

only need the new coil packs to arrive and the car is ready to have the last few things put back together and it'll be back on the road, hopefully in a week or two.

[wixer]

Finally got the car back on the road this week. I had an issue with a water leak, which was a pinched seal between the thermostat manifold and the V bank pipe. It was a tight fit when I first re-assembled it, now I know why.

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First drive to get the car MOT'd, this morning since top end rebuild. Car is noticeably smoother and more responsive, which is probably down to the cleaner, matched injectors and new correct spec spark plugs. Maybe the cleaning of the inlet manifold and attached parts also helps a tad.

[wixer]

Haven't added any updates to this thread for a while, mainly as I didn't undertake anything worthy over the winter but I think I've finally got to the bottom of an annoying electrical issue, that I've had since owning the car and a more recent electrical issue.

For three years of ownership, I've had the dash warning light come on, quite regularly, for error code 23, which is the front knock sensor. As I documented here in this thread, I replaced both knock sensors last year. Problem never went away. A few weeks ago having put the car back on the road for the summer, I started to investigate further. After a few emails to Kaz for advice etc. and doing various continuity & voltage checks at the two connector ends of the harness that connect the main ECU & knock sensor sub-harness, I found that the voltage to the front knock sensor was virtually non existent, 0.03v compared to the rear at 0.2v. The reading was the same at the ECU output. Conclusion was the ECU was faulty. Not sure where to go for repairing it, I asked a guy at work, who's the electrical specialist in one of workshops. He said he'd open it up and check the soldered joints, before I took it to a specialist ECU repairer.

He couldn't find anything significant, just some small cracks around some of the joints, so he re-soldered them anyway. He also did the same for my cooling fan control unit, as I've had the odd time where the radiator fan wasn't coming on and the temperature gauge getting a little too high for comfort. Another particularly annoying issue, as I've replaced what I thought was the cause, the coolant sensor into the engine but two years later, the problem re-occurred.

The good news is that both repairs seemed to have worked. The knock sensor warning hasn't come on in the last two journeys (it usually come on after 5 minutes of driving) and the cooling fan kicks in when it should.

The annoying thing is, I changed both knock sensors unnecessarily, keeping what I thought was the only good one and throwing the faulty one away.

I'm beginning to come to the conclusion, having had these issues and doing quite a bit of internet searching for NSX electrical issues, that the electrical units, that seem to give most issues, are mounted directly to the rear bulkhead panel and due to their ages & probable vibration issues, being closer to the engine, could be the cause of many annoying electrical problem, the main ones being, main relay, cooling fan ECU and main engine ECU issues. This is just my opinion but I shall certainly look to these areas for any future issues I might have.

[goldnsx]

It is adviseable to take the electronics boards into account when solving problems in a car of that age/usual mileage. But the NSX is built very good and quite easy to solve compared to today's cars.

I've once had a running on 5 cylinders problem in certain conditions only for about two years. Changed some of the parts you've mentioned above like engine coolant sensor, spark plugs etc. only to find out later that one of the lower injector seals got damaged during mounting the fuel rails some time back which caused a tiny air leak and messed up the air/fuel mixture in the corresponding cylinder. Problem solved, happy car, happy owner.

[Senninha]

I'm beginning to come to the conclusion, having had these issues and doing quite a bit of internet searching for NSX electrical issues, that the electrical units, that seem to give most issues, are mounted directly to the rear bulkhead panel and due to their ages & probable vibration issues, being closer to the engine, could be the cause of many annoying electrical problem, the main ones being, main relay, cooling fan ECU and main engine ECU issues. This is just my opinion but I shall certainly look to these areas for any future issues I might have.

Welcome back from hibernation Wixer ... addressing each of the boards and the main relay are actions most of us have or will complete, or in the habit of good preventative maintenance will be completing pro-actively.

Hope you get them all sorted and continue enjoying your NSX

[wixer]

As I counted my chickens a little too early in my last post/update and the dash light came on literally the following day from the post, I had to do a little more investigating, into the KS sensor issue.

This time I decided to remove the pin from the ECU connector to check the wiring to the actual pin. A little fiddly to do, especially if your eyes are over half a century old but with various magnifying lenses I managed to remove the D4 pin from the plastic connector block using some jewellery screwdrivers. (The internet providing some useful info on removing pins from a Honda OBD 1 connector). I was expecting/hoping for a poor wiring joint, or even a small piece of dust but no, it was attached as it should be. There appeared to be nothing wrong with the pin at all.

So the only thing I could conclude, after examining the pin, was either the small tension tabs perhaps being a little slack on the internal side of the pin, or they are broken and should attached at both of their ends, thus causing a poor electrical connection to the pins on the ECU. So very delicately I bent the tab slightly, so it would have more tension to the ECU PIN and snapped it back into the plastic connector housing.

So this time, a week and half has passed and the warning light has not returned, so I actually do now believe I've solved the issue. Hopefully this bit of info may help others before they perhaps spend many hours and possibly money on trying to solve a re-occuring annoying electrical problem.

Pic attached with an arrow pointing to the spring tab.
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[wixer]

So about time for an up date on my on going, gradual, rebuild of my NSX. This winter I've tackled the aircon system, it having never worked since I've owned the car and the condition of the condensers & motors when I removed them 3 years ago, god knows when it did last work. Over the last couple of weeks, I've finally got the two outboard aircon condensers back together. It's taken a while, as I've managed to source some second hand motors, one second hand condenser and one new from Amayama. I'm also replacing the dryer canister with a new one, as the small window on the top of the unit shows the internals looking a pale white-ish colour, rather than completely clear.

So with a bit of luck, I'll finally have working aircon in both my Hondas this year, as I've had to replace the condenser in the S2000. I suspect the S2000 will work straight after it gets re-filled but I think there will be further work to do on the NSX system, once it gets a re-fill.


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[wixer]

Thanks to Covid, I've just had a job done that I intended to do this time last year and that is having the air-con system re-gassed, now that I have a sealed system. I went to Bee Cool in Kettering this morning, as they can accommodate the old type systems & Dave the owner, is very knowledgeable on all vehicle air-con systems. I had the system gassed with RS24, as R12 basically unobtainable & illegal.

So, all well with the gassing & the system maintained the pressure, so no leaks after the partial rebuild last year.

BUT.... the compressor won't kick in. As the air-con has never worked in my ownership (5 years), the re gas was in effect, the next step in the rebuild of the air-con system. We swapped the horn & compressor relays over to check if the relay was/wasn't working but the horn worked with the compressor relay, so relay was ok.

So, my question is, where do I start next ? I don't mind replacing components but there maybe a better set of checks I can run through, to try & get to the fault that's stopping the compressor kicking in. I don't know whether the compressor actually works either, so need to get it working to see.

I'm going to do the CCU test firstly, as I suspect the issue is electrical but any other suggestions, would be appreciated.

Thanks in advance.

Cheers

[Kaz-kzukNA1]

Did the condenser fans operate?


Kaz

[wixer]

Did the condenser fans operate?


Kaz
Hi Kaz,

Thanks for replying.

Yes, the compressor fans have operated on their own (the main radiator fan didn't activate) but I'm unsure why they would, if the compressor isn't working & extracting heat from the car. What sensor is activating them ? The only thing I can think of is the Cooling Fan ECU is switching them on after looking at the wiring diagram.

I've also looked through the Workshop Manual & have followed some of the diagnostic procedures, as follows.

1. Shorted the terminals across the Triple Press Switch, Compressor did not activate. (Still want to check the Volts of the BRN/BLK wire here).
2. Checked the voltage at the PNK/ORN terminal of the Comp Clutch Relay & there is 12V, (10A fuse also good).
3. Checked the voltage at the YEL/BLK terminal of the Comp Clutch Relay & there is 10V.
4. Ran the 2 procedures for the CCU diagnostic, no issues with either of them.

Still to do.
1. Check Volts at RED wire in engine bay to Compressor & it's continuity to the Comp Clutch Relay terminal.
2. Swap the Comp Clutch Relay again with the Horn relay, to double check the actual relay is good.
3. Do the checks on Page 22-60 of the manual, for the Cooling Fan ECU.
Cheers.

[goldnsx]

Did you try 12 V directly to the comp clutch?

[wixer]

Did you try 12 V directly to the comp clutch?

Not yet, it's on my list of things to do today. I've been studying the Workshop Manual this morning & making a list of things to do & making sure I don't accidentally fry an ECU !

[goldnsx]

Not yet, it's on my list of things to do today. I've been studying the Workshop Manual this morning & making a list of things to do & making sure I don't accidentally fry an ECU !
It would be my first test. I once heard of an A/C stator failure.
Just undo the connector next to the oil stick and apply 12 V to the A/C coil at the compressor and see if it spins. If not you'll need a new stator/clutch unit for the compressor.

[wixer]

It would be my first test. I once heard of an A/C stator failure.
Just undo the connector next to the oil stick and apply 12 V to the A/C coil at the compressor and see if it spins. If not you'll need a new stator/clutch unit for the compressor.

Done this check applied 12V to the compressor & compressor clutch engages, so all would seem good with the compressor.

Still working through the other checks but already seeing some strange results. I have got 12V at the harness end of the compressor red wire intermittently. I thought it was due to the fact I had a jumper wire across the 2 terminals of the Triple Pressure Switch and when I reconnected it to the switch the 12V at the red wire went to 0V. Having repeated the test again with the jumper wire across the Press Switch, I now can't see 12V at the harness end of the compressor red wire..........

Currently checking relays & fuses again but all seems good still, so I'm beginning to suspect either the Cooling fan ECU or the PGM ECU but if one of the temperature sensors is faulty (ambient, interior), maybe they could cause one of the ECU's to switch off the 12V to the compressor......

[wixer]

Having spent nearly all of the day, going through a lot of the procedures in the Workshop Manual numerous times, I can get the Compressor to activate intermittently. I think the issue is with the Cooling Fan ECU as I can occasionally get the Compressor to activate by wiggling its connector. I can try the same thing again & it won't activate the Compressor. The only other thing I've found, is the Ambient Air Temp sensor is out of range of the specified Resistance levels.

Reading this post by Kaz,
http://www.nsxcb.co.uk/entry.php?981-Cooling-Fan-Control-Unit
it gives me more confidence in my conclusion.

[goldnsx]

The only other thing I've found, is the Ambient Air Temp sensor is out of range of the specified Resistance levels.
Do you mean the one in the bumper face?

Not sure where the A/C system gets get the info from exactly but the A/C is shot off at very low temps.

[Kaz-kzukNA1]

Have you ever noticed the rad fan start operating immediately after turning IGSW in P2 ON position even when the engine is cold?
Both R&L condenser fans and the eng bay fan (if you have one) could be triggered at the same time.

As your issue is intermittent and if not done yet, best re-soldering all of the joints inside the FCU (Fan Control Unit).
Quite a lot to re-solder but still DIY level.

The condenser fans and the compressor CL are controlled separately so even when the former spinning, the latter may not engage.


Inputs to the FCU:
Thermo sensor (mounted on the thermostat cover, different from the temperature sender unit for the temperature gauge or the TW sensor for the ECU)
CCU A/C request
Tripple Press Hi-Lo switch

Output from the FCU:
Rad fan Lo relay control (Low speed mode)
Rad fan Hi relay control (High speed mode, bypass the resistor block)
Eng bay fan relay control (if you have one)
R&L condenser fan relay control
ACS (A/C Switch) signal to ECU

A/C CCU:
Evaporator temperature sensor input
A/C On/Off request to FCU

ECU:
ACC (A/C Clutch) output signal controlling the A/C compressor CL relay.


This is how the A/C compressor CL is controlled.

1. At the CCU, if the Evaporator temperature is above 4degC AND manually or automatically the A/C On is requested, the CCU sends the A/C On request to the FCU.

2. If the Thermo sensor is below 130degC AND the Triple Press Hi-Lo switch is On, the FCU sends ACS request to ECU.

The all of the fans (Rad, R&L condenser, Eng bay ones) are controlled by the Thermo sensor and the A/C On/Off request from the CCU but without the Tripple Press Hi-Lo switch status.

Therefore, if the coolant is extremely hot like above 130degC OR the Tripple Press Hi-Lo switch detects abnormal refrigerant pressure (too high or too low), there is a situation where the CCU is requesting to engage the A/C compressor and while the condenser fans are spinning, the compressor CL won't engage as the FCU doesn't enable the ACS request to the ECU.

3. ECU receives the ACS request from the FCU and enables the A/C compressor CL relay through ACC signal.
At the same time, adjust the engine control based on ACS and Tripple Press MID switch status.


So, multiple controllers and sensors involved.


The outside temperature sensor at the front bumper is not used for the compressor CL control.
If disconnected, the CCU will just use 10degC as the failsafe data and carries on with the rest of the control.


You can force the CCU into the evaporator temperature control mode and send out A/C On request to FCU using the following method.

a. There is no need to start the engine. Just set IGSW into P2 ON position.

b. Press [ AUTO ] dial to power up the CCU if switched off at the last driving cycle.

c. Not required but to save the battery, set fan speed at MIN (1 click from auto mode).

d. Either press on the [ A/C ] switch on the CCU and get [ A/C ON ] on the display or turn the temperature dial all the way counter-clockwise to set it at 18degC.

This will force the CCU into evaporator temperature control mode.
If the evapo sensor is above 4degC, it will send out A/C On request signal to the FCU.


Kaz

[wixer]

Have you ever noticed the rad fan start operating immediately after turning IGSW in P2 ON position even when the engine is cold?
Both R&L condenser fans and the eng bay fan (if you have one) could be triggered at the same time.

As your issue is intermittent and if not done yet, best re-soldering all of the joints inside the FCU (Fan Control Unit).
Quite a lot to re-solder but still DIY level.

The condenser fans and the compressor CL are controlled separately so even when the former spinning, the latter may not engage.


Inputs to the FCU:
Thermo sensor (mounted on the thermostat cover, different from the temperature sender unit for the temperature gauge or the TW sensor for the ECU)
CCU A/C request
Tripple Press Hi-Lo switch

Output from the FCU:
Rad fan Lo relay control (Low speed mode)
Rad fan Hi relay control (High speed mode, bypass the resistor block)
Eng bay fan relay control (if you have one)
R&L condenser fan relay control
ACS (A/C Switch) signal to ECU

A/C CCU:
Evaporator temperature sensor input
A/C On/Off request to FCU

ECU:
ACC (A/C Clutch) output signal controlling the A/C compressor CL relay.


This is how the A/C compressor CL is controlled.

1. At the CCU, if the Evaporator temperature is above 4degC AND manually or automatically the A/C On is requested, the CCU sends the A/C On request to the FCU.

2. If the Thermo sensor is below 130degC AND the Triple Press Hi-Lo switch is On, the FCU sends ACS request to ECU.

The all of the fans (Rad, R&L condenser, Eng bay ones) are controlled by the Thermo sensor and the A/C On/Off request from the CCU but without the Tripple Press Hi-Lo switch status.

Therefore, if the coolant is extremely hot like above 130degC OR the Tripple Press Hi-Lo switch detects abnormal refrigerant pressure (too high or too low), there is a situation where the CCU is requesting to engage the A/C compressor and while the condenser fans are spinning, the compressor CL won't engage as the FCU doesn't enable the ACS request to the ECU.

3. ECU receives the ACS request from the FCU and enables the A/C compressor CL relay through ACC signal.
At the same time, adjust the engine control based on ACS and Tripple Press MID switch status.


So, multiple controllers and sensors involved.


The outside temperature sensor at the front bumper is not used for the compressor CL control.
If disconnected, the CCU will just use 10degC as the failsafe data and carries on with the rest of the control.


You can force the CCU into the evaporator temperature control mode and send out A/C On request to FCU using the following method.

a. There is no need to start the engine. Just set IGSW into P2 ON position.

b. Press [ AUTO ] dial to power up the CCU if switched off at the last driving cycle.

c. Not required but to save the battery, set fan speed at MIN (1 click from auto mode).

d. Either press on the [ A/C ] switch on the CCU and get [ A/C ON ] on the display or turn the temperature dial all the way counter-clockwise to set it at 18degC.

This will force the CCU into evaporator temperature control mode.
If the evapo sensor is above 4degC, it will send out A/C On request signal to the FCU.


Kaz

Thanks for this Kaz, it's answering some of the questions I have with regards the way the ECU's interact with each other, to control the cooling/A-C system. This info should help me determine what the problem is.

These are my answers to your questions.

1. Yes, both condenser fans can come on when the the engine is cold. Sometimes the first morning start of the day. This doesn't occur every time though.
2. I had the FCU re-soldered 2 years ago, after the main radiator fan not switching on & the temperature gauge creeping up a little too high for comfort. This repair did/has seemed to work for the radiator fan.

I've ordered a new FCU & Ambient Temp sensor from Amayama, which will either solve the problem or at least eliminate these two components.

I'll keep this post updated as and when I do more work on the car, when the parts arrive from Japan.

Cheers.

[wixer]

Minor update, checked the continuity of the wire (BLU/BLK) between the FCU & PGM-ECU & it's ok, no breakages.

Also took the FCU apart to look at the circuit board. I can't see any dry joints or leakage from any of the components but I guess the only definitive check is to replace the FCU.

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[Heineken]

One potential option is to re-flow all solder points - sometimes these cracks are thin as a hair and hard to detect visually.

[Kaz-kzukNA1]

You really need re-soldering all of the joints.
From your photo and what you mentioned, looks like you only re-soldered very limited number of joints in the past.

As Heineken mentioned above, you are looking for the hair line crack.


https://lh3.googleusercontent.com/pw/ACtC-3fUNiTXEQPF3gkTUU_uj9TLQcETcgheXOp83uPo1eEdh5CkSnm xVGSp-TpyDLoULeQy4xhoOZRlvBChtHk2BKXoBlJl3-gNF6mIyumVXBFYtGFN-ClyI77Pfv-qJMWooRlL2ll-_uOxWBxYbLDrZ53DkA=w1080-h608-no?authuser=0
This is one example.
As you already opened the FCU, you will know how far this photo was enlarged compared to the actual size of the soldering pad.
Arrows show some of the cracked joints.
In fact almost all of the joints in this photo are cracked.






https://lh3.googleusercontent.com/pw/ACtC-3fDUC0zeNXNzLi5Z9DNV_5tmEKQ_bVqYJuiSVuYhB_5SdULZ9T K1TaiCO34dZlnjgEj-5Ig3EPOjzDlW0O_LJXGMmrOz9I64pDvVmDQAYq1XgEoG0Ao5Vx EKtXI4TDIO7W_bAixThKFtPNivHbNg5wccQ=w1080-h486-no?authuser=0
Almost all of your photo are out of focus and not high enough resolution so hard to tell but even so, there are many suspicious joints.
This is from your 4th photo.

Circled ones very likely to be cracked, arrows are suspicious but hard to tell.


Kaz

[wixer]

Thanks for checking these out guys, with my eyes I couldn't see any issues but obviously I need another appointment at Specsavers.... Amazed you could enlarge my pics Kaz but glad you have.

Does anyone want a re-soldering job ? I wouldn't trust myself to do this & I thought a guy at work re-soldered all the joints but obviously not.

[wixer]

A minor update on the Air-con repair, to keep the post ticking over.

I received a new Fan ECU in the week, I had to get it from Canada, as Amayama are out of stock with no idea of when the unit will be available again. A bit annoying as I had to pay twice the Amayama price but this is all part of NSX ownership I guess, now they are getting old cars, mine having had it's 30th a couple of months ago.

I swapped the Fan ECU over this morning & started the car up. Firstly the condenser fans didn't immediately start up, which is a first. I then checked to see if the compressor was engaging & it wasn't, so I shorted the triple pressure switch & then it did engage. So it would appear that there was two faulty components, the ECU & the pressure switch.

So now I'm gradually working through the issues & eliminating the faults, so I've got the next ones to deal with.

1. I'm not so sure the temperature is getting cold enough. It's not the hottest day today (it is England in May) but even on 18deg temp & Auto setting I'm able to hold my hand against the face vents quite easily but this is with the car stationary. On a run & the recirc switched off, the temperature did seem to get colder. I should've taken my temperature gauge with me but I didn't, so I need to do another run out to check & have a search of the forums to see how cold the temperature should get on the lowest setting.

2. I have a new Triple Pressure Switch but it looks like I will have to get the system de-pressurised to swap them & if I do that, I'm debating whether I should strip the IP down & replace the elements in the HEVAC unit.

Also, many thanks to Heineken for offering to re-solder my old Fan ECU.

[wixer]

Today I did another check of the temperature coming out of the face vents in the car, whilst on a run & re-circ off & it was hovering around 13-14 degrees, which is pretty much the same as the ambient temperature today, in sunny Coventry.

So next plan of investigation is required to understand why.

Could the pump, although the clutch is spinning, not be working correctly ?

Could it be another sensor, sending an incorrect temperature to the FCU ?

Could it be the evaporator in the unit in the IP ?

I touched both the pipes next to the spare wheel, that lead into the interior, to see if either were cold but neither were as cold as I expected & were pretty much the same temperature as each other and this is with the compressor appearing to be working ok.

Any suggestions would be appreciated of where I turn to next ?

Cheers

[goldnsx]

The A/C compressor doesn't seem to work. Do you hear it kick in when pressing the A/C button to ON?
My A/C service station has two gauges to check the pressures while the A/C is running.
Are you sure that there is enough R134a in the system?

[wixer]

The A/C compressor doesn't seem to work. Do you hear it kick in when pressing the A/C button to ON?
My A/C service station has two gauges to check the pressures while the A/C is running.
Are you sure that there is enough R134a in the system?

Yes, compressor kicks in when the A/C button is pressed to ON & I pop the engine hatch to check I can see the pulley spinning, so it's definitely running.

I had the system filled last month with RS24, a replacement for R12, as the system was never modified for R134a & there's no signs of leakage.

I am going to speak to the company who charged the system, to see if they can check the pressures while the compressor is running, next week.

[wixer]

Finally got to the bottom of the non functional air-con, in my NSX.

I went back to Bee Cool in Kettering today, for them to try & diagnose why there's no cold air coming through the vents, with the air-con ON & the compressor engaged. Candidates were either the compressor clutch or the compressor unit. Having connected the car up to one of their air-con units, the gauges displayed no pressure in the cars system, only 2 months after it was fully re-charged by Bee Cool. There was no visible signs of a leak anywhere & no signs of green fluid on the garage floor, so the cars system was filled with Nitrogen gas & a detector used to find the leak.

The leak was found to be one of the shrader valves used for charging the system, so both were replaced & another pressure check done, this time resulting in the pressure maintaining itself. A quick swap of the triple pressure switch for a new item & the car was re-gassed again with RS24 & finally success, there is now cold air coming through the vents, so I have a fully functional air-con system for the first time since I've owned the car.

It's not very often a fix is so cheap on an NSX, I was planning a compressor replacement or repair, so glad it was something easy & a good lesson learned, to check the small easier parts first.

[goldnsx]

Glad that you've found it just before the hot summer time. As you say those neglected Schrader valves are much cheaper than any other part in the A/C system.

[Heineken]

Leaks at the Schrader valve can be a pain to identify the usual way since the area is already contaminated with leak finding dye even if there's no leak ..
So, good to hear that's fixed!

[goldnsx]

The easiest way to avoid problems is to change the Schrader valves every 10 years. You also change the valves with new tires for example.

They are not so hard to detect. The only part that makes it complicated is people are not thinking about them. :) If you have the retrofit kit installed correctly and open the plastic cap and you feel that there is some 'air' pressure while releasing the cap you have a leaking Schrader valve.

[Heineken]

Well, all my cars have slight pressure when releasing the plastic cap but their systems are not leaky :D

[wixer]

So the NSX tax bites back, as my 'little win' on the air-con, only requiring a couple of new shrader valves has now been offset by both the clutch master cylinder & brake master cylinder leaking.........

I can't find any record of them being replaced previously, in the cars history, so if they are 30 years old & have lasted 188,000 miles, then that's pretty damn good in my book. I remember having to replace the seals on my old Minis & Metros, what seemed like every few months, so hopefully I'll never have to replace them again.

Clutch unit replaced, brake cylinder on order from Amayama, so hopefully the car won't be off the road for long but if the weather changes as predicted, the S2000 will probably be more appropriate anyway.

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[wixer]

Some pics of the brake master cylinder replacement. Had to give the servo a touch up of paint before fitting the new cylinder, due to the brake fluid having corroded the paint & a slight covering of rust.

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[Kaz-kzukNA1]

Nice work.
Hard to tell from your photo but hope you removed the rubber gasket before the touch up.

If the master cyl was leaking, behind the gasket is where the brake fluid and the rust would sit.
Very rare but with the worst one I saw in the past, the fluid was actually held inside the booster.

Kaz

[wixer]

Yes Kaz, I removed the old gasket/seal before painting. :)

The cylinder was obviously leaking for a while but the brakes felt ok but now with a new cylinder I would say the pedal feel is firmer & the brakes feel a little sharper, as a result. I suspect, as there was a small leak of fluid, there would have been small amounts of air possibly getting into the cylinder causing the slight spongy-ness of the pedal feel.

Now back to fix the Air-Con, as it has stopped getting cold, again..... I suspect the evaporator matrix in the main HEVAC unit.... At least I had a months worth of cold air comfort.....:D


Nice work.
Hard to tell from your photo but hope you removed the rubber gasket before the touch up.

If the master cyl was leaking, behind the gasket is where the brake fluid and the rust would sit.
Very rare but with the worst one I saw in the past, the fluid was actually held inside the booster.

Kaz

[Kaz-kzukNA1]

.................

Now back to fix the Air-Con, as it has stopped getting cold, again..... I suspect the evaporator matrix in the main HEVAC unit.... At least I had a months worth of cold air comfort.....:D
Seems like you are chasing multiple A/C issues one at a time or you still have some leakage.
If it was fine for a month, I hope it's not evaporator related.

I believe you don't have the manifold gauge.

The RS24, R12a, etc are mixed/blended refrigerant so if leaked, the mixture ratio would change.

As a quick refrigerant level check, take a look at the sight glass on the drier/receiver while keeping the engine rpm above 1,000 - 1,500rpm and the CCU at freezing cold setting.
Ideally, you want doing this check on a very hot day as the exp. valve continuously changes its needle port diameter altering the pressure but at least, you can see whether you have low refrigerant or not as long as you can engage the compressor.

Kaz

[goldnsx]

Now back to fix the Air-Con, as it has stopped getting cold, again..... I suspect the evaporator matrix in the main HEVAC unit.... At least I had a months worth of cold air comfort.....:D
Sounds like a bigger leak. You've mentioned that it hold pressure after changing valves etc. Have you ever changed all (accessible) o-rings? If not you'll be faced with a long-running problem with your A/C system.

[wixer]

As a quick refrigerant level check, take a look at the sight glass on the drier/receiver while keeping the engine rpm above 1,000 - 1,500rpm and the CCU at freezing cold setting.
Ideally, you want doing this check on a very hot day as the exp. valve continuously changes its needle port diameter altering the pressure but at least, you can see whether you have low refrigerant or not as long as you can engage the compressor.

Kaz

I'll give this a go Kaz but the cold pipe (in the front end), which I believe is from the compressor, is no longer cold to the touch. When the air-con was briefly working, it would get cold enough, that you couldn't hold your hand on it, so until I get another pressure check, I pretty convinced the gas has escaped again.

And to Golds point, I haven't changed all O rings so, I think this winter I will probably rebuild the rest of the system.

[wixer]

Time for an update to this thread, with this winters project. A partial transmission rebuild, new driveshafts & new clutch.I haven't found any info in the cars history documents, of any replacement or rebuilding of the driveshafts but I doubt that they are untouched in nearly 190,000 miles. They clunk when taking up the drive, so they definitely need replacing. I've decided to replace, rather than rebuild (although I probably will rebuild them & keep as spares) with some from Insane Shafts, as their prices for a pair of 500 HP rated shafts are just a bit more than a single new OEM item from Amayama. I could go down the rebuild but I suspect that current shafts might well be worn too far, for just a rebuild but time will tell.... I am going to rebuild the intermediate shaft fixed joint with new bearings and seals also.

There is record of one clutch replacement but this was some time ago & the pedal bite is near the top of the travel & there's always been a slight judder, even after replacing a broken engine mount & re-torquing them in the correct sequence. So a new one will be ordered from Amayama, as soon as the gearbox is out & all parts have been inspected.

So far I've removed the old driveshafts, which sounds quite easy but requires all the lower rear suspension links to be dis-assembled to allow the rear hubs to swing enough to allow the driveshafts to pop out of the diff. They were proving to be a bit stubborn, so I removed the band securing the inner boot & split the joint there & will then remove the inner joint. All the gearbox cables & harnesses have also been disconnected & oil drained.

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Old shafts not fully inspected yet but as you can see, the grease isn't looking the best...

[wixer]

A little more progress,

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but now Im stuck..... I can't get the gearbox off past this point, it's moved about a inch & I'm uncertain of the intermediate shaft length that engages with the engine side, to know how far the gearbox still needs to slide off the splines. From my memory probably a couple more inches........

Anyone tackled this job before singled handedly ? That can offer any tips ? They would be appreciated.

I guess another pair of hands would help no end. Time to call some favours in...

[goldtop]

^ One thing I have read many times over - did you release the clutch fork release? The one that's held by a spring and needs to be pulled out slightly to allow the trans to separate.

(Apologies if this is teaching grandma to suck eggs - it's a whole new world to me, and full of surprises and gotchas!)

[Kaz-kzukNA1]

[16:12 Edit; just realised, goldtop was 3min quicker than my post below....]
Release fork?

Pull it out of the saddle and just let it hanging inside the CL case.

Also, it's hard to see from your photo but looked as if you still have the big long grey front crossbeam in place.
Remove it to have extra room.

Kaz

[wixer]

Thanks both for the replies. I haven't removed the clutch lever.

Currently sucking some eggs, thanks Goldtop :D

Probably will remove the front crossmember, although I've undone the bolts but as you say Kaz, it'll make life easier.

[PeterW]

Hi Wixer,

I'm enjoying this thread. It inspires me to get out and do more on my NSX!

Regarding drive shafts, did you consider buying new ones from RockAuto? They're ridiculously cheap, £54.86 for the L and £82.93 for the R, Trakmotive manual transmission. They also have the left one from GSP for £114.17. I've got a Trakmotive one from them on the left side and it seems to be fine. At the time I decided mine needed doing, they only listed the left one otherwise I would have bought both. There have been posts on Prime about the quality of the Trakmotive ones. Some people weren't happy with the amount of backlash and it seemed to be a bit of a lottery whether you got one with that problem. But at that price I thought it was worth a punt and mine was fine.

Peter

[wixer]

Hi Peter,

Glad I've been inspiring you to do some DIY-ing on your car, I'll keep posting. :D

I did look at RockAuto's shafts but felt the Insane Shafts as they're rated at 500HP should give the same length of durability, as a set of OEM shafts on a stock NSX but time will tell.

Glad you have positive feedback on the Trakmotive parts, as it's always good to get recommendations from owners that have tried non OEM parts, it helps other owners make a better judgement to make a decision on their own cars.

Cheers

[wixer]

This weekends progress on the transmission re-fresh.
Dropped the gearbox quite easily, once the fork has been moved out of the way, thanks again guys....

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A lot of congealed dust, it's definitely time to do this job.
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Fork has no grease, probably not surprising considering the last clutch change was years ago.
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and there was no rubber boot on the fork, something I'd never noticed.
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[wixer]

More photos.

Looking at the state of all the clutch assembly, I can see why there was a juddering when engaging.

Think the crank oil seal needs to be replaced.
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My new favourite tool made removing the rusty flywheel an easy job
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bearing completely dry

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Haven't measured the cutch plates thicknesses yet.
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[mutley]

Now this is interesting, I have had my clutch donw twince during my ownership, and I have never had a rubber boot on my clutch fork either! is that a thing? if so, anyone know where to get that part?

Cheers,
Jim

[goldtop]

Are we talking about item 6 on this page?

https://www.amayama.com/en/genuine-catalogs/epc/honda-europe/nsx/1995_5MT/21732/transmission/M__0300

Not too spendy, if so.

Might an early mechanic misplaced/forgot it when swapping out a slave cylinder?

[Pride]

Wix, do you think the excessive amount of surface rust you have is a direct result of not having a clutch fork boot??? 🤔

[wixer]

To answer your questions,

Yes, it is a thing & yes it's item 6 on the diagram. My S2000 has the boot on it, as I gave the clutch fork a re-greasing a few weeks ago, so definitely should have one on the NSX. I would guess that during a slave cylinder replacement/service, it was not put back on.

The rust on the flywheel is probably down to my car having sat outside or in damp conditions, in a previous owners custody and it not been used on the road enough to help dry things off. Some other areas of corrosion I've found over the last few years would also point to this lack of use. The flywheel, although well covered (assuming the small cover is attached to your car), isn't air tight so moisture can always condense on cold metal parts. This is why using your car all year round is a must, if it's sat outside & not in a nice dry warm garage. I keep my S2000 outside now, so it will be used all year, the only time I won't use it, is when there's salt on the roads.

[mutley]

Well there you go, looks like this part:

https://www.parts-honda.uk/honda-cars/NSX/1991/NSX/TRANSMISSION/CLUTCH-RELEASE/17SL001/M__0300/2/23825


https://www.parts-honda.uk/honda-cars/assignment_spare_parts/22841PR8010

[wixer]

Well there you go, looks like this part:

https://www.parts-honda.uk/honda-cars/NSX/1991/NSX/TRANSMISSION/CLUTCH-RELEASE/17SL001/M__0300/2/23825


https://www.parts-honda.uk/honda-cars/assignment_spare_parts/22841PR8010


Only £12 from Amayama :D

[mutley]

Only £12 from Amayama :D

Absolutely, NEVER go to Honda unless you really have to

[wixer]

Most parts arrived this week, although the clutch is still 'out for delivery' according to Parcelforce & started to clean the parts. Took best part of a day to clean the gearbox, there was a lot of baked on dirt/grease, probably 30 years worth...

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Need to repair a couple of threads in the gearbox, a couple have more or less been stripped by a prior removal.

Anyone had experience with using helicoils or inserts as DIY ? Not something I've ever used, so be interested in whether it's something to tackle myself or take the gearbox to an engineering company.

[Kaz-kzukNA1]

Helicoil is good for this purpose and used it at several different section of our NSX.
Addition to the gbox, the mating bolt thread at the suspension control arm, curved/L-shaped holder bracket between the eng/gbox, etc all suffer from oxidation.
When removing the bolt, if you felt something not quite right, just mark it so that you can check and deal with it before re-assembly.

For Eng block, timesert is better but it requires extra meat to be removed during the preparation and the jig/die is quite expensive.

For other places, helicoil, v-coil or the likes are good enough.
Just make sure to check the material of the inserts and the required length for your purpose.

Kaz

[wixer]

Thanks Kaz.

The damaged threads are as you say, the one gearbox side of the L-shaped strut bracket & one of the lower fixings on the gearbox main engine mountings. Both low on the car, so more susceptible to corrosion, as little protection to the elements.

Two kits ordered for the different thread sizes M10x1.25mm & M12x1.25mm

[wixer]

Today I started to re-assemble the clutch. Crank end seal replaced & new flywheel attached. I've had a few dry runs with the clutch assembly, as it's a tad more tricky than a single plate clutch. I've also used the old assembly as reference, to make sure I'm totally familiar with the set-up.

New release bearing guide
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clutch fork & pivot. Noticable wear on them
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Old release bearing guide, lot of wear. My guess is this was never replaced when the clutch was last replaced. There's an actual ridge where the metal has worn away.
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new flywheel on & torqued up.
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[wixer]

dry build.

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old plate with the new one
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crank oil seal
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[wixer]

Todays adventures.....

start to disassemble the intermediate shaft to replace bearing & seals.
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repairing the few stripped threads with helicoils
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clutch assembly going on.
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greasing the release bearing with Honda Urea grease as per Kaz's recommendation
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[Kaz-kzukNA1]

4th photo.
That's way too much grease applied.
It could cause issue in the longer term.

What I normally do is to first just apply really thin coat covering the entire internal wall.
Really thin that you can hardly see the actual grease and just oil film on the surface.

Then, 'pack' the narrow groove/channel evenly inside the release bearing where it slides over the release bearing guide.

I can't even see the groove/channel in your photo.....
Keep the grease height/thickness flush/close to the internal wall.

Just before the installation of the trans case, apply really thin coat of grease around the release bearing guide.

As long as you've invested in high quality grease, this should keep the release bearing and the guide healthy until the next CL service.

For some reason, the OEM Urea grease outside of Japan is in a pot and the grease has green colour.
Mine is in big tube and the grease is dark grey.

Kaz

[wixer]

OK thanks Kaz, I'll remove some of the grease.

[wixer]

Happy New Year everyone, hope you all had a great Christmas.

More progress, although I'm not getting in the garage as often as I'd like...... especially over the Christmas holidays, thanks to the Moderna booster.

Gearbox back in place. Awkward job to do with only one pair of hands, the small transmission lift helped but another pair of hands would've been useful for holding the clutch fork in a position to not hinder the final few cm's of mating the gearbox. In the end a piece of bent wire had to do.

For anyone else who may take this job on, I would say the main thing to remember is .....CLUTCH FORK, CLUTCH FORK, CLUTCH FORK !!! It hinders the removal & re-fitting of the gearbox if not held in a suitable position.



Clutch slave cylinder in place, now with dust boot. Worth mentioning the boot makes aligning the cylinder shaft awkward to align into the clutch fork, it's quite easy to think the shaft is engaged into the socket in the fork but there's a good chance it won't be, which wouldn't be ideal when you first press the clutch pedal.
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New bearing guide.
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LH driveshaft in place. I'm fitting brand new shafts from Insane Shafts.
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[wixer]

A bit more work done this weekend. Started to replace the Air-con pip seals & remove the compressor & have it checked out/reconditioned, while the system has no charge. Looking along all the pipe runs, there's no visible sign of a leak, which is annoying, as where did all the gas go ?? There was no pressure in the system when I split the first joint.

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Belt tensioner needs a new pulley, it's quite noisy, so a few more parts to order from Amayama.
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[Kaz-kzukNA1]

5th photo.

Although you mentioned that your 'system was checked out/reconditioned', does it include the compressor?

That sticky looking debris at the service plate and the front housing is most likely the compressor oil.

How much oil did you manage to recover from the compressor body?

Not only the small o-rings at each pipe/hose fittings, the octagonal big gasket under the service plate and also the large diameter o-ring at the front and rear housing of the compressor body are common places for the leakage.


Kaz

[wixer]

Hi Kaz,
The compressor hasn't been checked yet, my guess is that this is the first time it's been removed in it's 31 years of age. I only had the system re-charged last year, after the condensers were replaced.

The sticky debris seems to be quite old IMO, I was expecting more signs of a fresh leakage from last summer, when the system stopped working and so far I've found none.

I haven't tried to drain any oil out of the compressor yet, so something to do but when the pipes were removed, there was hardly any seepage of oil from the hoses.

Is the compressor a unit a DIY-er could re-con ? Or is best for a professional ? I suspect specialist tools will be required.

Ive found this place https://automotivecompressor.co.uk and was thinking of giving them a try. Open to any other recommendations though.

[Kaz-kzukNA1]

Long time ago, I used to use compressor overhaul service in Japan because the re-built replacement was always readily available and cheaper than getting re-manufactured one from abroad.


If your compressor was operated with low oil level, chances are that you already have some level of worn metal piston, slider, disc, etc.

Therefore, refurbishing the existing one may not be the best option.


In fact, now-a-days, you can get hold of re-manufactured Denso 10PA15C one (new, not used) at reasonable price and since you have full access to the area, good time replacing it with a new one.


If your existing compressor is the original one with unknown service history of the a/c system, most likely, it will have some internal metal wear and tired rubber gasket + o-ring.

Remember that when you lose the refrigerant, you are also losing the compressor oil because it travels through the entire system along the refrigerant.


I remember you visited Bee Cool few times and re-charged using RS24 so your existing system must be still R12 spec from the factory.


http://www.nsxcb.co.uk/entry.php?2321-Denso-Compressor-471-1193-4Seasons-Drier-33412-part-1

Please refer to the above blog for the available compressor option.

Very important to read the comment section of the above link for the mounting bracket offset, etc.


I normally recommend owners to switch to R134a and get Denso 471-1193 if doing major A/C refresh.

471-1193 requires the use of 97+ mounting bracket or transfer your existing CL/pulley set if you want to keep the original bracket.

You can also get re-manufactured new 91-96 CL/pulley set if you are staying with the original bracket.

Unfortunately, 471-1193 is out of stock at Rockauto at the moment but may be available somewhere else.


471-1194 is also R134a but for some reason, Desno fitted the pulley with the smaller diameter so not good.

Not the end of the world.

Just use the new compressor body and decide what to do with the bracket and the CL/pulley set.

You already have 91-96 mounting bracket so if your existing CL/pulley set is healthy, just swap it in.

Or, same as above, the re-manufactured new 91-96 CL/pulley set is available so can be replaced if your exiting set is already worn out.


If you want to use the 97+ bracket and if you are happy to acknowledge that it's not cost effective, then you could convert 471-1194 (91-96 offset) to -1193 spec (97+ offset) using the OEM 97+ CL/pulley set .

Only make sense if you can't wait for the out of stock 471-1193 to become available again and if you are keen to shift the compressor away from the aftermarket header.

Only about 8mm shift and the OEM 97+ CL/pulley set is not cheap if bought new....

AFAIK, there is no aftermarket 97+ CL/pulley set available but I think someone on here found the used replacement from different make/model.

I think it was from one of the Toyota model???


471-1424 is for R12 so the compressor oil is mineral (ND-OIL6) and not PAG (ND-OIL8, for the R134a and not for R12).

Some owners went for this one to prevent the hassle of dealing with the different spec of mounting bracket, CL/pulley diameter and the field coil connector.

If using R134a, you need to drain the fresh mineral oil out of the new compressor and replace it with ND-OIL8.

If you want to keep the mineral oil for some reason, use RS24.

POE can be used and seemed to be much better now so could be good option as it can handle both type of refrigerant but in the past, I was not fan of it.


If staying with the mineral oil, make sure to add extra amount as I 'think' Denso followed the old spec and not the updated total system amount through the Honda/Acuta TSB.

Most likely the 471-1424 is delivered with only 80ml of mineral oil when it should have been 120 +/-10ml.

You can easily measure it and tiny amount will be always left inside the compressor.



As you already exposed the system to the atmosphere, regardless of the option selected, you should consider flushing the system especially if replacing the compressor.

You don't want contaminated oil left inside the pipe, hose, evapo, condensor.

You must replace the drier/receiver again because you exposed the system long enough.

Cheap and if ordering the compressor from Rockauto, just get it at the same time.

If you are doing DIY, may want getting spare one for future usage in case you may find new issue somewhere else.


I normally leave the drier fitting and the compressor connection until the very last moment to minimise the moisture absorbed.

If replacing the compressor, should replace exp valve as well.

Very cheap but be careful when trying to remove the existing one.

The connection is most likely seized by now and with the limited space at the opening of the evapo behind the blower motor fan, you could struggle using the double wrenches.

If you kink the aluminium pipe, you may end up replacing the evapo that will force you to take out the entire dashboard out of the cabin.

Not something you want to do during the winter time as all these aged plastic parts can easily break unless warmed up first.


Good luck.

Kaz

[wixer]

Thanks Kaz, this is an excellent idea & if I'd have stopped to think, it is the ideal time to convert the system to R134a, which will make any future servicing far easier, not being dependant on RS24.

Looking at the 471-1193, with a '97 mounting bracket, would seem to make sense to me, as I'm not sure the CL/pulley from my current unit is worth taking the risk with, just to retain the current '91 mounting bracket. I've been quoted anywhere from £150-£280 to re-con the current unit, so from a cost effectiveness point of view, it wouldn't be much more expensive, to upgrade to the '97 set-up. I guess a R134a re-gas will be cheaper than another RS24 re-gas aswell.

The evaporator was replaced a few years ago but the system hasn't been disconnected until i removed the compressor a few days ago. I've covered the open hoses securely to prevent moisture. So pretty confident there will be no moisture ingress into the system.

Thanks again.

[wixer]

Continuing on from the my last post, I've bought a new air-con compressor. Had to get the 471-1194 model from the US, as 47-1193 wasn't available, as Kaz had pointed out. I'm now waiting on a '97 mounting bracket & a '97 clutch/actuator assy, the later coming from Rock Auto. Strangely Rock Auto specify the same replacement part number for both a '91 MY & '97 MY, whereas I was under the impression the two assys were different, due to the mounting bracket offsets as documented in Kaz's posts.

Rock Auto part numbers

AC Delco 154750
Four Seasons 47598

AC Delco not currently available & the Four Seasons assy is also listed for a 1994 Toyota Celica.

Amayama part numbers are

'91 389-PR7-A01 (full clutch & stator assy)
'97 389-PR7-A04 Clutch 38924-PR7-A01 Stator Assy

I was sort of hoping to use my current '91 mounting bracket & swap my clutch/stator assy but looking at the clutch, I think a replacement is due, eve though it did seem to function well enough, during the brief time the air-con worked last summer.

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[britlude]

i think on the later cars the AC pump was moved outward with the updated bracket to get it away from the revised exhaust manifold, and the pulley was moved inward towards the pump body to correct the difference

[Kaz-kzukNA1]

Hi, Wix.

471-1194 has smaller pulley diameter (about 125mm) compared to the OEM one or the 471-1193 (about 140mm).

Hard to see in your photo but the connector on the -1194 would be also wrong.


By the way, 471-1193 just got back in stock at the Rockauto.


AFAIK, there is no aftermarket 97+ CL/Pulley/Field coil set with the proper offset matching the 97+ mounting bracket listed under the Acura NSX section of the Rockauto site.

Therefore, the two parts listed (#154750 & #47598) in your post are most likely to be 91-96 offset spec.

Could you measure the diameter?

Also, kindly take a photo showing the mounting offset, just like the two yellow arrows as per the photo shown later.


Not the end of the world as your existing friction material looked worn out so best replaced with your new aftermarket ones.

Most likely, the aftermarket one will have 91-96 mounting offset, just like your existing one.

Just re-use your existing 91 - 96 mounting bracket and not the 97+ one.

Please keep your 97+ mounting bracket as I'm quite sure someone will need it when doing the A/C Refresh.

I may even buy it from you in the future if I was asked to do another A/C Refresh.


Since this is your build thread, didn't want posting too many photos and tried placed multiple links to my blog, etc.

However, for this topic, probably best placing the actual photos here so that you can refer to them easily in the future.




The A/C belt is installed over the 3 x pulley - the crank, the idler and the compressor one.

While the offset of the mounting bracket was changed for 97+, the crank and the idler pulley stayed at the same position/alignment for all year models.

Thus, the geometry of the compressor pulley had to be changed.



https://lh3.googleusercontent.com/pw/AM-JKLWkcZgcB8GsJquOqjv_ybxH7F0En5iyrzfid3EravJy9tL6v CyIL2vtep6RVBWG9gd-oC6B6RyV0tc1MSwE7q41oHaVtr6exqUqFuefFTxJXSOh98dOG0 p2HJL6b31k0BJvri8fhaXRQ_RgZVVXZ8yy4Q=w1080-h608-no?authuser=0
This is the offset of the mounting bracket.

The compressor body is exactly the same as 10PA15C for all year models.

Same dimension, mounting geometry, etc and just R12 or R134a refrigerant difference.

The mating thread on the eng block side kept the same geometry.

The blue line is the position of the a/c idler pulley bracket.

Stayed the same for all models and thus, straight line shows the same geometry on both the 91-96 and 97+ mounting brackets.


I also measured the distance between the eng block mounting hole at the top right of the bracket and the threaded hole at the top left for fixing the compressor.

With the 97+ mounting bracket, the entire compressor body would be shifted outward about 8mm.

Thus, the compressor pulley design had to compensate for it.





https://lh3.googleusercontent.com/pw/AM-JKLU1oq7NOq3RFr4LG_3mb3wn5MieQlXuDd7_RtuC5Vg8pGX6y 49ocXSbsmU0GyhRJKvj2cZCHKg69FPtMzVitRkyUL-pltjCXSyY_RCH05g4vrrMx-ZEwtFkLHXTDYCB6lUQhH4je1TWxoxIFKJ-JIzE7g=w1080-h581-no?authuser=0

https://lh3.googleusercontent.com/pw/AM-JKLWvyr-By-ycb67E2ltoeTCpqwElnZoXVBntduwxyHQXOOwFW52qwhpgMRkT NfgpFCQ7d8saIcdAgSjaH35eNuWWXRpNbZM6PdBuJzKPbgi_UD qAwGWV2xlKt8LHlCrNk0XLCdKRIDHK8-843mQWbPP8RQ=w1080-h654-no?authuser=0
As indicated by the two arrows, 97+ pulley set has changed its design and being mounted much closer to the compressor body compared to the 91-96 pulley.

So, always keep the relationship between the mounting bracket and the compressor pulley spec.


Kaz

[wixer]

Hi Kaz,

As soon as all the parts arrive, I'll post an update to answer your questions.

I'm with you though on the new pulley/clutch from Rock Auto, I think it will be '91-'96 spec. Hopefully with the '97 mounting bracket & whatever the pulley does turn out to be, I have all the components to mount the new compressor correctly.

The connector on 471-1194 does indeed have the wrong electrical connector & the smaller diameter pulley, which I will measure when next in the garage.

[wixer]

Parts have arrived, so here's some photos to answer some of the questions on an earlier post.

New pulley & clutch from Rock Auto, large diameter
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pulley from new compressor 471-1194, small diameter
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Rock Auto pulley against new Compressor 471-1194
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and against the original R12 compressor from my car
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Rock Auto Actuator against original R12 are the same
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and '97 mounting bracket.
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and a few more parts
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I think the Rock Auto pulley/clutch assy is the later '97 offset, as it doesn't have the same offset as the original off my car. Confirmation when I've actually assembled them to the new compressor.

[Kaz-kzukNA1]

Hi, Wix.
Thank you for taking your time for all these feedback.
Much appreciated.



https://lh3.googleusercontent.com/pw/AM-JKLUa-V1268Y8uUueIeCx0ubt8gIequ2uZa2SwiZijd4y-yjo5X-Z4H4UxLzDSgmAZtfiXgKGoxfU-JhXuhyIFQE80Zgz0GwLAZMXnuzamZmlP9PkBFNDr7l_x4HV5Su _447XNVUjHRTybBQuD9rAt3YzbQ=w1080-h608-no?authuser=0
Interesting to see where the pulley sits once the snap ring installed.

Kaz

[wixer]

No probs Kaz, glad to help confirm all the fitment issues with a compressor change to R134.

Original R12 compressor hose attachment plate removed, internals look clean, which is a good sign.
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This compares the original '91-'96 compressor pulley alignment with the 471-1194 with the Rock Auto pulley assy. As can be seen, the Rock Auto assy is most definitely the later '97 offset, the belt run being closer to the compressor body.
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New tensioner pulley & adjustment screw attached, the bracket cleaned up quite well.
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New compressor & Rock Auto pulley attached to the original '91-'96 compressor mounting bracket. Photo doesn't really, due to fish effects but there is a definite mis-alignment.
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Old '91-'96 bracket off the engine & the new '97 bracket.
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Completed assy now mounted to the '97 bracket.
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with the belt on, which shows perfect alignment.
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Changed a few more air-con pipe seals, one of the old & new from the compressor hoses. Needless to say but they weren't in the best shape, so maybe the seals were the cause of the gas leakage.
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So final spec, for future reference.

Rock Auto pulley/clutch/actuator assy - Four Seasons (no Denso parts available at time of ordering) - 47598 ('97 MY Pulley offset)
Denso R134 compressor 471-1194
'97 MY compressor mounting bracket 38930-PR7-A01

[wixer]

More fun in the garage today,

dry fit of new driveshaft & intermediate shaft
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New intermediate shaft has a larger shaft diameter, I guess this was an specification upgrade during the cars life.
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and more air-con seal changes
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[wixer]

Hopefully this will be the final chapter in this winters overhaul. Fitted the last few bits back to the car, filled the gearbox with MTF3 & torqued everything up. Then came the moment to start the car & test to see that the clutch operated correctly, with it still on the ramp. BUT, I couldn't engage any gears properly & couldn't get into reverse at all, there was definitely no proper dis-engagement of the clutch........As you might guess, the air became a tad blue, at the possibility of having to remove the gearbox & clutch again.

After an email to Kaz & doing a few searches on the forums, I had a few ideas. Kaz suggested re-doing the clutch initialisation procedure & checking the pedal travel adjustment. Apparently the mid plate could get knocked out of place, if you struggle to get the gearbox back onto the engine, which did happen to me, working alone. I'd definitely recommend getting an assistant for anyone else who might attempt to do a DIY clutch change.

I re-set the initialisation and clutch pedal travel as per Kaz's video & re tested to see if the gears selected correctly & success, every gear could be engaged easily including reverse. I have yet to test drive the car, as I need to borrow a torque wrench to tighten the driveshaft axle nuts up, my largest torque wrench maxes out at 210n/m & the nut is 335n/m but fingers crossed, there'll be no more gear selection issues when I do go for a drive.

I also replaced the two air-con pipe seals at the front bulkhead. Not the easiest of tasks.....

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but the two seals were in good shape, compared to some of the other seals I've replaced from the under floor connections but new ones now in the cleaned up joints.