Stubborn Crank Pulley Bolt

[Mark N]

I would love to come but I am having a problem trying to replace a stubborn crankshaft pulley which is really beginning to annoy me.

[britlude]

I would love to come but I am having a problem trying to replace a stubborn crankshaft pulley which is really beginning to annoy me.#

you really need 3/4" socket set, 1/2" just isn't up to it!

[Mark N]

Don't say that I Have just spent £100 on a larger torque wrench which is 1/2 drive also :D
#

you really need 3/4" socket set, 1/2" just isn't up to it!

[Hagasan]

You shouldn't really use torque wrenches to undo bolts/nuts...


Don't say that I Have just spent £100 on a larger torque wrench which is 1/2 drive also :D

[NSXGB]

http://www.amazon.co.uk/Sealey-AK7312-1000mm-4-inch-Breaker/dp/B000R9ZB76

Plus impact extension & socket to suit...

I was lucky, mine came off after a short while with a 24v Sealey buzz gun...it did muller about 3 extension bars on the way though (non impact).

Make sure you grease the bolt properly before reassembly so next time is easier.

[Problem Child]

#you really need 3/4" socket set, 1/2" just isn't up to it!I'll ask HRH if I can borrow hers!

[Mark N]

You shouldn't really use torque wrenches to undo bolts/nuts...

Its a reversible torque wrench the idea was to set the torque to 180 lbft that is used to secure the bolt and gradually increase it. By doing that I know exactly what torque i am putting on the bolt because the last thing you want to do is shear the bolt .

[Hagasan]

Its a reversible torque wrench the idea was to set the torque to 180 lbft that is used to secure the bolt and gradually increase it. By doing that I know exactly what torque i am putting on the bolt because the last thing you want to do is shear the bolt .

Most of them usually are. I may be wrong but just was advised in the past not to use one for undoing because it knock the calibration off. Torque when tightening is obviously more critical which is why I would have that a breaker bar is sufficient and easier?

Like I said, I could be wrong or what I was told is wrong? Maybe someone else knows better?

[Kaz-kzukNA1]

If the torque wrench is calibrated and designed to be used in torque inspection mode, then it can be used for loosening the bolt but obviously, you only use it for the inspection purpose and not like ordinary ratchet for every day usage.
Once you hit the specified number of torque operation, you will need to re-cal it or replace it with a new one so you really don't want to use the torque wrench for other purpose.

I don't know the spec of your torque wrench but if you selected it for tightening the crank pulley bolt (245Nm) and being as 1/2sq, it is very likely that the max range is about 350Nm.

If you are already struggling to loosen the crank bolt with 1/2sq tools, I'm afraid it is very likely that you will need to apply much higher torque than that and you don't want to damage your new torque wrench beyond its spec.
I have never measured it accurately but from time to time, it feels like I'm applying easily twice the amount of specified torque on really stubborn crank bolt (500Nm+ ???).

I know some people uses 3/4” or even 1” impact wrench at lower torque setting in order to loosen this bolt and never saw it seared off.
If using any extention, then as others suggested, forget about 1/2sq tools and go for at least 3/4 ones.

As mentioned several times on here, while it is done on other engines, one thing you must never do on NSX engine is to lock the flywheel side to hold the crank for loosening the bolt.
Always use the proper adaptor on the crank pulley HEX hole to lock the pulley itself and then loosen the bolt.


Apology for going off topic.
As a courtesy, I have attached the latest attendee list from post #39.






Kaz

[Mark N]

My Original torque wrench was only calibrated to 150 lbs.ft.The new one I have purchased is calibrated to 250 lbs.ft and is designed for both left hand and right hand threads so what my plan is is to set the wrench say 180 lbs.ft and try to undo the bolt once the wrench clicks ie reaches the applied torque, stop applying the pressure re-set to 190 lbs.ft and try again gradually increasing the torque in 10 lbs .ft increments hoping that it will come undone before I reach the limit of my new torque wrench thus not damaging it or putting it out of calibration.
I have purchased the special tool to hold the crank pulley as you advised Kaz.
My only concern is what is the maximum torque I can put on this bolt with out the risk of shearing it. Hopefully it will come loose not much over 180 lbs.ft setting but there will be a point that I am not prepared to go pass so then it will have to go to a main dealer to be done.

[duncan]

Forget your local main dealer, find a local 'Fred in a shed' who services trucks and commercials. He will have a 3/4" or 1" chatter gun; with you jacking the car up and removing the wheel he should be able to break the bond. You can then re-torque the nut, return home and play to your hearts content, all for the cost of a drink.

[britlude]

the only reason bolts shear when coming out is when the threads are rusty, and you unwind the bolt and pull the rust into the gap, eventually filling it sufficiently to break the bolt.... with the crank pulley bolt you wont break the bolt coming out. if you do it was never going to come out anyway! and as the thread is completely enclosed within the crankshaft end, it won't have rusted.

when the bolt is tightened to torque, it's the stretch of the bolt that holds it tight. undoing it you have to release this pressure, plus the 'sticktion' between the bolt head and the pulley, so it'll always take more to release than the torque applied...

as duncan suggests, a trip to a heavy duty equipped garage, in this case it is just brute force and ignorance, usually requiring a big breaker bar and swearing!

[Sudesh]

Totally agree! Had to use a heavy impact gun to remove a few.


the only reason bolts shear when coming out is when the threads are rusty, and you unwind the bolt and pull the rust into the gap, eventually filling it sufficiently to break the bolt.... with the crank pulley bolt you wont break the bolt coming out. if you do it was never going to come out anyway! and as the thread is completely enclosed within the crankshaft end, it won't have rusted.

when the bolt is tightened to torque, it's the stretch of the bolt that holds it tight. undoing it you have to release this pressure, plus the 'sticktion' between the bolt head and the pulley, so it'll always take more to release than the torque applied...

as duncan suggests, a trip to a heavy duty equipped garage, in this case it is just brute force and ignorance, usually requiring a big breaker bar and swearing!

[goldnsx]

Make sure you grease the bolt properly before reassembly so next time is easier.
ONLY the threads, NEVER the head of the bolt or you'll have to use much more torque to release it next time. The contact area of the bolt to the pulley has to be completely dry and free of grease.

[Kaz-kzukNA1]

You should lubricate the bolt thread plus the bolt head where it meets the washer.

This is where the corrosion can happen resulting in excessive torque required on loosening the bolt.

You don't need to degrease the area where the washer meets the crank pulley. In fact it's better not to.
Just wipe off the area with the shop towel.

There is a diagram in the workshop manual on where to lubricate, clean or degrease so just follow it.
The key is to never let the oil to get in contact with the TB and prepare the pulley bolt properly.


Kaz

[Mark N]

Thanks for all your advice.
I carried out the job at the weekend and it only took one hour :D
Kaz I did exactly what it said in the manual as you describe above .

I used my new torque wrench to see what torque was required to undo the nut and to my surprise it came loose at 160 lbs ft so clearly its been removed before and not torqued up correctly. Anyway I fitted the plate that helps protect the timing belt in case the pulley ever fails ,which I had purchased from a fellow member some time ago . Then I fitted the new pulley torqued to correct setting replaced all belts went for a drive and rechecked the torque setting again.

Job done.

As I said before thanks for all the advice
Mark

[goldnsx]

The SM says the opposite. I would not expect heavy corrosion of the bolt anyway.

Happy wrenching!

[NSXGB]

Im sure sure there is an update to the SM you are using. I have a .pdf of the page somewhere, thought I posted it before but can't find it at the moment. I will seek it out.




The SM says the opposite. I would not expect heavy corrosion of the bolt anyway.

Happy wrenching!

[Kaz-kzukNA1]

For the clarification, that's from the old manual. The torque spec in Nm is also old but not a problem.
The vague description such as 'Apply to the bolt thread, but not to the surface that contacts the washer' was removed in the later manuals.

There are many mistakes in the workshop manual and these were corrected/updated later through the 'Service Information News'.
In Japan, Honda released new workshop manual just for the engine service and it states, 'do not degrease the crank pulley except the mating surface towards the TB drive pulley', 'Apply oil to the bolt thread and to the bolt head where it meets the washer'. I have more than 10 workshop manuals with latest information.
The latest Japanese and English manuals shows the same info for the crank pulley area as follows;

https://lh5.googleusercontent.com/-UQwQR6LpfgQ/U6s6kF-VcpI/AAAAAAAARWA/DbFGjD5PUZc/s640/CrankPulley.jpg https://lh6.googleusercontent.com/-F61XgDlbsE8/U6s6jYqVpbI/AAAAAAAARV4/Fy5GRRtrQYI/s640/CrankPulleyBolt.jpg

[nobby]

Reviving this thread ... as some of you already know my crankshaft pulley decided to let go on the last day of the NSX Euro tour. The pulley was only replaced 4 years ago with just over 30k done. Only for the pulley shield I was staring down the barrel of a gun.

I need to get the car on the road again for next month's Silverstone Classic event.

Where do you get hold of the proper adaptor on the crank pulley HEX hole to lock the pulley in order to get the thing removed?

Any links/advice greatly appreciated

Thanks

Andrew

[Kaz-kzukNA1]

Hi, Andrew.

I believe your NSX is MT model and not the early-early 91 Acura MT engine so you need the attachment with 45mm HEX.
Unless you are doing DIY, just let your nearby Honda garage to replace the pulley as they should have the 45mm attachment although they would be using the 50mm one more frequently these days.

The parts no. in the above diagram is for the US market and not recognised in the UK parts system.

If you are not sourcing it from US, then you need the 07JAB-0010300 (45mm, MT NSX) or 07JAB-0010400 (50mm, AT NSX) with the holder handle 07JAB-001020B.
However, they are not cheap and not cost effective unless you are using these tools regularly.

You may be able to find the 45mm HEX attachment on amazon, ebay, etc but no experience with the ones bought from there.
Just searched on amazon and [Laser 3729 Crank Pulley Holder, dispatched from and sold by Amazon] seemed to be 45mm HEX but never bought one so don't know whether it can be used or not.
Since it’s sold directly from amazon, you could return it if it doesn’t fit.....

OEM and the Laser 3729 are flat design.
There are several 45mm attachment with offset shape on the market but not sure these can be used in that tight space.


You may be able to borrow the tool from your good old friend if doing quick DIY???
I’m afraid I need to keep mine here for the next service.....


Kaz

[nobby]

Hi Kaz

thanks for response to my question

Yes 94 manual

my good friend is hard to get hold off at the moment

Thanks for offering but i knew you would need yours! :)

cheers

andrew

[NSXGB]

I have the Laser 3729 but use it on it's own bar rather than a breaker bar. I have used it three times without issue.


If anyone needs a 50mm tool for their auto, I have one I don't need, just needs a bar.

[nobby]

thanks simon

good to know

[Hagasan]

Hi Andrew,

did they not replace the pulley in Holland? Or are you just removing it again to fit a new shield? Good luck finishing it off completely.. See you next month..

Gary

[nigel]

Got mine from Amazon as Kaz advised.
If I recall, it was about 15 quid or so but that doesn't include shipping to the UK and of course the queens 17% but worth the investment.
These are NSXs so the proper tool is the way to go and not really that much to help be sure there won't be any c*ck ups on a known tough bolt removal.

As before, DON'T forget to use anti-seize on the bolt threads and washer before re-installation.

Cheers
nigel