Crank pulley

[bernev]

Having Kaz on the site is probably the most amazing thing about it. Here is a man who knows so much about NSX that it puts all the Honda dealers put together to shame. Anyway, when we all read the problems about peoples cars we start worrying about our own... particularly if Honda dealers don't even look at the problem areas.

The two quick questions from me doesn't appear to be covered in any of the threads. These are: is what actually causes the separation of the crank pulley. is it heat cycles? Is it normal weathering and humidity? rust? Or just rubber going brittle over time like tyres. Clearly, I will now inspect the pulley on my car but this might give me an understanding about how likely it is to happen. Second, it would appear that the crank pulley is not actually connected to the TB but interferes with it once its become detached - correct.

Bernev/Clive

[NSXGB]

I think you've pretty much answered all your questions correctly...

As I understand it, when the pulley starts to separate, it will spin out of true and make contact the lower TB cover. As the cover gets chewed, fragments of the cover could break off and fall between the timing belt and actual crankshaft pulley. If you are unlucky this will cause the TB to jump teeth and cause contact between valves and pistons or the belt could snap completely.

WRT breakdown, Kaz mentions in his blog that heat is a factor - refernce to aftermarket headers. I would agree with a combination of this and the other factors you mention all contribute to its deterioration.

[bernev]

Thanks NSXGB. I will look at my pulley today. It's on normal pipes and hasn't done many miles so it should be okay. But any evidence of wobble and off I will go to somebody competent to have it fixed. I just wish there were more competent people around to do it. Honda dealers generally don't inspire confidence.

[Nick Graves]

It also sometimes happens to Preludes too.

One ought to hear it rubbing against the TB cover.

[bernev]

Well I've had a look from the top and all seems okay although it is hard to get really good top down view. No wobble but there was an ominous "glue detaching itself" noise as I tried to wobble the pulley. I suspect it will need doing soon even if its okay now.

[NSXGB]

Well I've had a look from the top and all seems okay although it is hard to get really good top down view. No wobble but there was an ominous "glue detaching itself" noise as I tried to wobble the pulley. I suspect it will need doing soon even if its okay now.

If that is the case, I think you should not drive the car until you confirm that noise is not the CP as it could go any time...

Thinking aloud (Kaz or someone else with greater knowledge could confirm), maybe if you remove the accessory belts then grab the pulley by hand and wobble, if you get the same noise or worse, it will confirm whether it's separating. You obviously should not be able to split a good one by hand, however strong you are so if it were me, I'd be quite rough with it and you'll find out soon enough. You'll have to do this from underneath. If you have any doubt, get it recovered to a garage where you can get it changed. Unless you have the tools to do it yourself?

[bernev]

Thanks. I've had a go at pulling it about from the bottom and it doesn't move at all and the sides seem parallel by feel. When I get time I will take the rear wheel off and look at it in more detail. If there is a problem I will then take it to a dealer. It is not on the verge of collapse. The car is rarely run but I will take a close look at the pulley when I next start it up and if there is any wobble I will stop it there and then. Can somebody point me out the best way to source a new pulley to avoid HUK prices. I will buy one in any case together with a TB. Can Kaz confirm it's okay to have them on the shelf for a long while before they are fitted. The issue here is that the car has only done 10000 miles and although I do not use it (due to other things getting in the way), I do intend to keep it for life and reinstate it when the time is right. That's why I'm in no hurry to do a TB service (it hasn't been done since 2002 when it had 6000 miles) because there is little point in doing it and then keeping it in the garage for the next four/five years and have to do it all again for no benefit.

[nobby]

daliracing.com, keeps these in stock and a very decent price and he is very decent regarding ship costs etc

you will almost certainly get hit with customs etc as hmrc and parcelforce are in cahoots, but MJ helps out on declaration etc

MJ has not the best reputation on here, but at this moment in time there is a few of us on here that use him and no issues.

since i bought my car last year i have spent k's with MJ, and just waiting to pick up a set of headers next week from him

the other place is an acura d'ship that others use here.

but the pulley is a stock item with dali so no big wait times

kaz may have them in stock



Thanks. I've had a go at pulling it about from the bottom and it doesn't move at all and the sides seem parallel by feel. When I get time I will take the rear wheel off and look at it in more detail. If there is a problem I will then take it to a dealer. It is not on the verge of collapse. The car is rarely run but I will take a close look at the pulley when I next start it up and if there is any wobble I will stop it there and then. Can somebody point me out the best way to source a new pulley to avoid HUK prices. I will buy one in any case together with a TB. Can Kaz confirm it's okay to have them on the shelf for a long while before they are fitted. The issue here is that the car has only done 10000 miles and although I do not use it (due to other things getting in the way), I do intend to keep it for life and reinstate it when the time is right. That's why I'm in no hurry to do a TB service (it hasn't been done since 2002 when it had 6000 miles) because there is little point in doing it and then keeping it in the garage for the next four/five years and have to do it all again for no benefit.

[bernev]

Thanks Nobby I take it that MJ is the man behind daliracing?

[NSXGB]

bernev. Have a search and be aware of how MJ @ Dali runs his 'business'. You have been warned, if you order from him after that, it's up to you. I sang his praises after my first two orders, then I was stung...

A lot of us use actual Acura dealers in the USA which are run as PROPER COMPANIES so you have a better chance of sorting things out should they go wrong. The Acura dealers are as cheap or cheaper than him anyway. SOS will also supply OEM parts, but are slightly more expensive than dealing direct with an Acura dealer.

[bernev]

Noted NSXGB. I am quite risk averse so I will not touch daliracing. Can anybody point me in the direction of an acura dealer that us Brits have used and equally that is used to dealing with us, including shipping and customs! I will then take it from there. Many thanks

[NSXGB]

Noted NSXGB. I am quite risk averse so I will not touch daliracing. Can anybody point me in the direction of an acura dealer that us Brits have used and equally that is used to dealing with us, including shipping and customs! I will then take it from there. Many thanks


Tim Poliniak
Internet Parts Sales
Acura of Peoria
www.oemacuraparts.com


NIC TERREY
NTERREY@FINDLAYAUTO.COM
FINDLAY ACURA
315 AUTO MALL DR.
HENDERSON, NV 89014
PHONE# 702-982-4160
FAX# 702-982-4166


There's a couple for you to try. Should be ~$230. Even if you pay all duties & taxes above board, I reckon it will cost you ~£215 as opposed to £435 from HUK.
I don't know whether your's is AT or MT, bear in mind that they are different.

[bernev]

Thanks a lot - it's a manual. I will get in touch with them soon

[nobby]

not getting into a 'war of words' regarding Dali, I know owners here have had problems, but i can only discuss my own experiences. MJ has been fine for me and others, when things are in stock etc everything is grand. sometimes communication can be quiet at times but he gets the job done in the end.

he is also good value for money etc as well and i can only say at this time he has sorted me out.

hope you get ur parts wherever you decide to go

[nigel]

Reference to the Harmonic Balance Pulley; You can check it by hand and it can feel ok but usually they come unglued at speed and cause a catastrophic failure all at once, immediate and expensive.
As ours cars age along with that some of the glues that are used in manufacture break down with age and temp and the crankshaft balance pulley is one place you don't want to take a chance considering the repair cost to a destroyed engine, verses the price of a new harmonic balance pulley.

Cheers
nigel

[Alf Tupper]

I bought my crank pulley from vtecdirect.com. They are a British company who are a vendor on nsxcb and offered a very good price of £185 (manual version). It took a few weeks to arrive, as it had to come from overseas, but a good deal I think and without the added complications of exchange rates, customs etc.

http://www.vtecdirect.com/online/cgi-bin/cp-app.cgi?seo=cat--Mechanical--NA1_Engine_mech

[Kaz-kzukNA1]

Seems like there are some confusions within this thread on how to check the crank pulley as well as what will happen if it fails so hope the following info will clarify them especially for the new owners.


First of all, the definition of the terms.

Crank Pulley:
Consists of two parts. The ‘Pulley Housing’ and the ‘Weight’.




https://lh5.googleusercontent.com/-eNhuvrcs6R0/Ty8MZ_hmsaI/AAAAAAAAApI/EXyX6XBaX4I/s640/IMG_0092.JPG
View from the Tyre side



https://lh5.googleusercontent.com/-8S7_ZbVKa6g/Ty8MahaDsxI/AAAAAAAAApU/0UfoAS4ZirA/s640/IMG_0093.JPG
View from the TB side
With this specific Crank pulley, you can see a single dimple (at about 11 o'clock position) on the Weight. Each Crank Pulley is carefully balanced and the dimple is the result of balancing process.




https://lh3.googleusercontent.com/-VqQBKW6BGQg/Ty8MZA0b0qI/AAAAAAAAApA/YaIAhjcHTGo/s640/Separated.jpg
The failed Crank Pulley
As you can see, the Weight is bonded to the Pulley Housing at one edge only. It is bonded by a rubber like material.





https://lh5.googleusercontent.com/-Zdvg2vwlJ6g/Ty8McJXFngI/AAAAAAAAApg/IC27OlBP42o/s640/IMG_0091.JPG
The main purpose of the Crank Pulley is to protect the TB by shifting the resonance frequency causing excessive fatigue on the TB at certain rpm. Also, it needs to act as the damper when the A/C compressor clutch switches On and Off hence, somewhat very little bonding method used and there is no filling or potting at the gap between the Weight and the Pulley Housing.

Don’t even think about filling these gap with some sort of material because each Crank Pulley is carefully balanced once assembled. This is why you see one or two dimples at the Weight surface.


The Pulley Housing is bolted directly to the end of the crank shaft at 245Nm so you won’t be able to wiggle it. If you feel any rattle, you have a serious engine failure.

Even if the Weight detached itself from the Pulley Housing, the latter will stay on the crank shaft and thus, won’t cause any issues. It’s the Weight that will eventually chew into the TB lower cover and the TB.

The Crank Pulley is located outside of the TB lower cover and thus, it can be replaced at any time without removing any major parts related to the TB. Just need to remove and adjust the ACG and A/C belts during the process.

In order to check the Crank Pulley, you must wiggle the Weight and NOT the Pulley Housing because of the above reason.
It is best to wedge in the pry bar between the edge of oil pan and the Weight to wiggle it. Due to the narrow space, you may not be able to apply enough force by using your finger to wiggle it.

(Continues to the next post...)

[Kaz-kzukNA1]

https://lh4.googleusercontent.com/-hgwhFRK8HBQ/Ty8uAOHIIUI/AAAAAAAAApo/Wk6ZvdhPOl8/s640/IMG_0090.JPG
Once you have checked the Crank Pulley while the engine is not running, then start the engine and look at the Crank Pulley from above. You must wear proper cloth and take extra caution not to get too close to the spinning ACG belt.

As you can see, the weight is slightly sticking out from the Pulley Housing.





https://lh3.googleusercontent.com/-t_bIPFtPQT8/Ty8MbUSChMI/AAAAAAAAApc/uc-10MsyxEY/s640/IMG_0089.JPG
The two lines (light blue) created by the edge of the Weight and the Pulley Housing should be in parallel and especially, the line by the Weight should be steady and no wobbly movement.


The cause of the Crank Pulley failure is mainly by the sudden changes in rpm (acceleration, deceleration), thermal shock and the age.

The Weight and the Pulley Housing are metal while the bonding material between the two is like a rubber/potting.
Therefore, two different materials (metal and rubber) with different expansion rate and characteristic.

When we first started experiencing this failure in Japan, it happened on the NSX heavily used on the track. By using the car on track, the heat from the engine (oil pan, Front header, etc) will significantly heat up the entire Crank Pulley and then suddenly, it will be cooled down by stopping the engine.
As it was used on track, it will go through hard acceleration as well as deceleration many times causing sharp increase and decrease of rpm at the Crank Pulley resulting in twisting the bonding material.
The rubber like material will age over the years and it will be accelerated by the heat, twisting motion, vibration, etc. Among the NSX Specialist, the Crank Pulley became the ‘must’ item to be replaced at the time of TB service and also regular inspection was recommended for track usage.

Later, we started to see the same failure on NSX with very little mileage so that’s when lots of owners in Japan started to replace their Crank Pulley at regular interval. This caused back order of Crank Pulley for a while in Japan.

[Edit: So, low annual mileage or low total mileage won't prevent this failure from happening on your NSX. I saw the issue on several NSX with less than 20K miles.]

Due to different expansion rate, eventually the bonding material will peel off from the Pulley Housing and leaving the Weight to detach itself.

I won’t worry too much about the shelf life of the Crank Pulley. It will indeed affect the life span but it is not kept close to the heat source like the engine and as long as you replace it at every TB service for street driving condition, you should be safe.


If you don’t need it urgently, I would contact Andy at Vtecdirect. I normally order it directly to Honda Parts Japan but when I want to keep one Crank Pulley in stock, I just contact him. It is best to give him a call as he is very busy and may not be able to access the email.
Make sure to order the correct model. Different part # for MT and AT.

Kaz

[bernev]

Kaz

Thanks. You remain an icon:). Fabulous advice - clear, informative and non-sensational. I have no idea when I will do my car (TB and crank pulley) but will keep use to a minimum until I'm called up by you for a health check - I enrolled over 18 months ago! I look forward to meeting you whenever that might be - just let me know. Clive/Bernev

[bernev]

Just to round this off - I have bought a crank pulley from VTECdirect and will fit it when I can. thanks all for your help! Clive

[Kaz-kzukNA1]

Kaz

Thanks. You remain an icon:). Fabulous advice - clear, informative and non-sensational. I have no idea when I will do my car (TB and crank pulley) but will keep use to a minimum until I'm called up by you for a health check - I enrolled over 18 months ago! I look forward to meeting you whenever that might be - just let me know. Clive/Bernev
Thank you for the kind words, Clive.
Still, my knowledge and skill level are nowhere near to my master…
There is always someone ahead of you…

As I don’t have your mobile no., I hope you will see this post and check your email.
It would be nice if you can reply back to it including your mobile info so that we can arrange the service for the future.

Regards,
Kaz