T-Belt busted @99,000

patrickseto · 2 March 2004

Hi everyone,

A tech friend of mine's working on a 1991 NSX 5-spd with busted T-belt @ 99,000 miles. All T-belt related parts (W/P, tensioners, seals...etc) were ordered from me (genuine parts) and being put on this past weekend. It turned out to be bent valves and possible crack head/s! Can NSXs' heads be service and rebuilt? Any suggestions?? He called me late this afternoon and I couldn't find out cause my dealer in the mainland has already closed. What other possibly obstacles may he come across? Figure I should ask the pros here. Any feedback will be appreciated. Thank you.

Aloha,

Pat

Vytas · 2 March 2004

Really sad to hear about this failure. I presume it was the original belt that failed given that it was way beyond the time and mileage service interval. It was inevitable that this would happen.

Repairing an NSX engine with a broken timing belt is not going to be cheap. Expect the repair cost to be about $6,000-$8,000 (from what I heard) after all is said and done. Spending $1200 on the required service would have prevented this disaster.

Another alternative would be to locate a used NSX engine.

patrickseto · 2 March 2004

Hi Vytas,

Are those heads non-rebuildable at all? If it's feasible, what else should we be aware of? Say, non-common (unforeseen) parts that we might need during the process. Please shed some lite, thank you.

Pat

4AU4LIFE · 2 March 2004

Man, that is a bummer.

sjs · 2 March 2004

It is unlikely that anything would have happened to make the heads technically non-repairable, but "practical" is another matter. According to Honda you aren't even supposed to replace the valve seats but technically it could be done.

Assuming nothing broke loose and rattled around for awhile, such as a valve head or guide, then damage may be limited to valves, guides, and possibly piston tops. If something did break off and the engines was allowed to run, then entire combustion chambers could be gouged up along with seats, pistons and cylinder walls. But even a badly gouged combustion chamber can be filled and re-cut as I have done on other aluminum heads. Not that I’d recommend it, but it can be done. The one place where there might be a risk of a cracked head is around valve guides but that is fairly unlikely and can be tested for.

Somebody mark this down as a confirmed belt failure since it is often debated just how long you can risk waiting. Of course we know nothing else about the life and use of the car, but that would be splitting hairs anyway.

steveny · 2 March 2004

That sucks. Sorry to hear about it.

matteni · 2 March 2004

patrickseto said:
Hi everyone,

A tech friend of mine's working on a 1991 NSX 5-spd with busted T-belt @ 99,000 miles. All T-belt related parts (W/P, tensioners, seals...etc) were ordered from me (genuine parts) and being put on this past weekend. It turned out to be bent valves and possible crack head/s! Can NSXs' heads be service and rebuilt? Any suggestions?? He called me late this afternoon and I couldn't find out cause my dealer in the mainland has already closed. What other possibly obstacles may he come across? Figure I should ask the pros here. Any feedback will be appreciated. Thank you.

Aloha,

Pat

This is the first I have directly heard of an NSX timing belt failure. It would be a big help if your budy could get some more information for the community (original belt, original owner, condition of valves, condition of head, condition of block, cost estimates, etc.).

Thanks in advance...

Tony Montoya · 3 March 2004

Thanks for reporting the timing belt failure.

goodbread · 3 March 2004

Tbelt failure

Sorry to hear about the castrophe but look on the bright side. Now, you'll have a chance to tear open that wonderful motor and do all the blueprinting you ever dreamed of! I had a similar experience with an Alfa Romeo 30 years ago and once together and running it was worth the experience. Of course, there is a minor price difference between an NSX engine and the Alfa 4-banger. Buona Fortuna! (good luck)

coolnsx · 3 March 2004

This gives all of us a wake-up call when we jerk around with the Acura replacement specifications. I've got a '94 Legend with 50K and I changed the timing belt after purchase. The downside is just way to expensive IMO. My '97 NSX has 34K and won't go much longer without being changed along with the water pump.

patrickseto · 3 March 2004

Thanks all,

I've got to seeing the vehicle in person this afternoon, its condition: above average.

I've talked to my buddy at the dealer, it's confirmed do-able and the heads are servicable... valve grind kit costs around $5XX. (I am getting 30-35% over dealer cost + freight).

Dropping engine with cradle seems to be the only way to perform this task.

More than happy to keep you folks posted.

Aloha,

Pat

myf16 · 3 March 2004

Was this car ever tracked or supercharged, or was it a totally stock car driven on the street?

patrickseto · 3 March 2004

Hi myf16,

AFAIK, it's all stock except rims and tires. Doesn't look like it's been tracked cos no track here in Kona lol...

Pat

matteni · 3 March 2004

patrickseto said:
Thanks all,

I've got to seeing the vehicle in person this afternoon, its condition: above average.

I've talked to my buddy at the dealer, it's confirmed do-able and the heads are servicable... valve grind kit costs around $5XX. (I am getting 30-35% over dealer cost + freight).

Dropping engine with cradle seems to be the only way to perform this task.

More than happy to keep you folks posted.

Aloha,

Pat

Any estimate on the amount for the repairs?

DanO · 3 March 2004

You don't have to drop the engine to remove the heads, but in this case it might turn out to be a good idea. Dropping the engine makes it much easier to do the head work and might result in a better finished product. If he doesn’t already, I recommend that your friend get a service manual and get well acquainted with it!

It is possible that only two cylinders were damaged. Personally (and I’m not a mechanic) I’d install the new t-belt on the car as is. Then do a leakdown test on each cylinder to see where you stand. You may find that the damage is only limited to one head and in that case, it might be easier to remove just the one head w/o removing the engine.

I think the best case is that two cylinders were damaged: exhaust valves on one and intake on the other and that the damage was limited to one head. Valves and seals are relatively inexpensive and a machine shop should make quick work of it. You might consider replacing all the seals since the head is out.

Look through the SM and note all the gaskets that will need to be replaced when reassembling. The spool valve gaskets and cam seals are notorious for leaking so these should be absolutely replaced. The owner may also want to consider replacing all the hoses. You may need to replace some of the larger heater hoses if you have to cut them off.

Remember to rubber band the rocker arms together like the service manual shows when removing the cams. You’ll need a good 10mm hex socket to remove the rocker shaft plugs (not 100% sure on the size, but your mechanic can check). Your mechanic may also need the special tools for adjusting the valve clearance and the special tool for holding the pulley while trying to remove the crankshaft pulley bolt.

Good luck and keep us informed!

DanO

patrickseto · 4 March 2004

Hello DanO,

Thanks for the info and certainly keep you guys posted.

In the near future I may want to get myself an NSX...

Aloha,

Pat

Meeyatch1 · 11 March 2004

I had to rebuild the bottom end of my '91 NSX and it was over $10,000.

patrickseto · 11 March 2004

Meeyatch1,

10,000 dollars!!! I am sorry to hear that... brah.

Here's some update for you all:

1) Gabe, my tech has already removed both heads from NSX;

2) He'll be stopping by my shop tomorrow to drop them off;

3) I'll then decide where to ship it out for rebuilt, any suggestions or recommendations would be greatly appreciated;

4) Before I send'em out, I'll take a few shots and post'em here.

Aloha,

Pat

kenjiMR · 12 March 2004

patrickseto said:
Hi myf16,

AFAIK, it's all stock except rims and tires. Doesn't look like it's been tracked cos no track here in Kona lol...

Pat

man, thats funny. You probably have the only NSX on the Big Isle. I grew up in Hilo and wish today I could drive my car back home sometime. If my old high school friends could see it, they would get a kick.

patrickseto · 12 March 2004

kenjiMR,

Around 3 NSXes running in Kona town... dunno if Hilo has any, I bet that are a few... FYI, even Vipers there are at least 2 on West Hawaii, 1 in Hilo!

Pat

satan_srv · 12 March 2004

If I were you I would source another NSX motor and put the new t-belt and parts on it. Sending the heads out and paying for all that work is a lot of downtime and costs that you don't need. I'll see if I can source you a JDM motor.

I'd be interested in your busted one.

Joel

sjs · 12 March 2004

satan_srv said:
...I'd be interested in your busted one.

Joel

Me too.

kenjiMR · 12 March 2004

patrickseto said:
kenjiMR,

Around 3 NSXes running in Kona town... dunno if Hilo has any, I bet that are a few... FYI, even Vipers there are at least 2 on West Hawaii, 1 in Hilo!

Pat

interesting. the island must be upgrading.

I used to live there 8 years ago, back then there definitely were no NSXs. I saw a Porsche 996TT last time I was back home 2 years ago though. Do you run saddleback road? There are really no places to drive such fast cars in Hawaii. You should ship the car to the US for NSXPO in the future.

patrickseto · 13 March 2004

Hello sjs,

I don't own an NSX, posting these messages to share/let know and try to gather info to help out my tech friend who's working on the vehicle. I may, in the future, get me an early model one, that's all I can afford to finance it lol... I agree the NSX design is everlasting, it's a timeless machine... you all are a bunch of lucky dudes... Aloha!

Pat

Meeyatch1 · 23 March 2004

I am getting the timing belt, water pump, and accessory belts replaced on my '94 NSX this Friday with just over 76,000 miles...I just do not want to take the chance anymore.

T-Belt busted @99,000

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