Do NSX-heads warp ?

[DutchBlackNsx]

After the incident i had with the coolanttank going cracked, and the overheating after that, my coolingsystem has never been the same.
Everytime again there was air in the system, resulting in to high temperature in many cases (not blowing smoke, just the gauge indicating to high temp, and also the sound of the expansiontankvalve blowing off)
Lately i can hear the tank blowing off more often, even if my engine is not 'that' hot (gauge reads fine).
So my conclusion was that i have a leaky haedgasket (if 'm lucky).
I got it checked out last week, and the check-fluid went from transparent to yellow in a couple of seconds (bad sign), indicating that there is (a lot) exhaust gases in my coolant.

So my question is, how often does it happen that the head goes warped on NSX engines?


Mich

 

[DanO]

I don’t think it is common at all with a stock NSX with a properly maintained engine. But, I remember master mechanic Mark Bash saying that once the engine has been overheated, there is no telling what will happen down the road. Apparently our engines don’t like to be overheated.

Did you have a compression or leakdown test performed? If so what are the numbers? Replacing the head gaskets is a real labor intensive project, the engine does not have to come out of the car but taking it out may actually save on total labor costs.

DanO

 

[Lud]

There is nothing NSX-specific here... Aluminum engines simply do NOT like overheating. It is very common to blow a head gasket or warp/crack the heads if they seriously overheat.

Based on your comment about the exhaust gas in the coolant, it sounds like you have a very seious problem. I wouldn't drive the car until you fix it or you can end up damaging many more components.

[This message has been edited by Lud (edited 29 December 2002).]

 

[DutchBlackNsx]

Thankx guys for your replies.

The thing is, that i'm under the impression that the engine never got 'seriously' overheated, because i never had a smoking engine, just the gauge telling it's too hot, but not realy 'cooking', like steam comming out.

I've driven like this for months now.

It's going to have the headers installed somewhere next week or so, so they also can lift the heads at the same time....


Mich

 

[Tony Montoya]

Mine overheated once and there was no long term damage as far as I know. I had the coolant changed and took a long drive to some hilly country in Ontario. I lugged the motor up hill in top gear and then stopped at the side of the road with the AC on. It just spit a little coolant out.

 

[DanO]

Originally posted by DutchBlackNsx:
It's going to have the headers installed somewhere next week or so, so they also can lift the heads at the same time....

I agree that a header installation is a good opportunity to pull the heads off because the headers are a difficult part of the head removal process. That being said, removing the heads is a labor-intensive process, please take a good look at the engine section regarding head removal pages 6-28 – 6-56. To give you an idea of the labor involved. As an example, look at step 9 on page 6-50 that shows the torque sequence for the front and rear cam holders-it takes a long time to tighten these down properly—and that’s a relatively easy part of the procedure. Again, although it is not necessary to remove the engine, it may turn out to be a less expensive option because of reduced labor costs and higher-quality workmanship (it’s a real pain to bend over the engine compartment for a few days).

You will want to have all the new gaskets, seals, belts, crush washers and hoses ready to go. Do you plan on taking the heads to a machine shop? Are you going to replace your valve seals—it may be a good time to do it?

Good luck,

DanO

 

[David]

Lud is correct in his observations that this is true with all aluminum engines/aluminum heads. They react very badly to overheating, even for short periods.

If your coolant system is pressurizing, you need to find out why. The head gasket (s) is the first obvious choice. If one is failing, you will probably see signs of it with a visual inspection, but replace them both even if they look good. Also, have the heads checked to make sure they are still true and mill them if they are not. Then, pressure test the motor BEFORE you put it back in the car. Nobody does this, but it is a very important step. You do not want to have to pull the motor two days in a row (ask me how I know).

A couple of weeks ago, a friend and I pulled my motor and completely disassembled the heads in about 3 1/2 hours. Its a pain, but think how much easier your header installation is going to be. ; )

Also, if you drop the motor, do any engine service that might be due in the next year or so (t-belt, heater hoses, clutch, etc.). You will be glad you did later. For example, installing the headers takes about 20 leasurely min. with the motor out of the car. T-belt takes about 10 min. to install and index with the motor out.

Good luck.

[This message has been edited by David (edited 29 December 2002).]

 

[DutchBlackNsx]

Thankx Dano for the Reply.

It is a lot of work, but then, i installed shortgears without a lift

The problem overhere is not so much on the price of labor, but more the quality of labour (not that the the hourly rate is cheap).
I had my share of Honda dealers overhere, who ripped me off two years ago for 5000 USD on a 60K service, where i ended up with stripped bolts in my drivetrain. Offcourse they denied all when complaining (suprise, suprise). The nearest by very well experienced dealer is in the Eastern Germany, approx 900 Kilometers.

Mark Basch is a long drive to

, so i'm left with guys who can do it in there 'evening hours', that will be the most experienced guy (though not NSX-certified), or with a Honda racingshop who does all sort of Honda tunning and FI installations. They seem to work nicely on there cars, but a NSX is different IMO, not much, but a little bit, especially when it comes to scratches and small damage as a result of working on the engine.

Dropping the engine would be a good option, but installing new stuff in the engine is a little bit too much, especially since the thing is running fine, and has only 80Kmiles on it.
I don't now if blueprinting is an option, but as far as i heard, it's useless on a NSX.
(is it?).

Anyway, the new headgasket was going to go in anyway, since i want to go on the bottle in the near future.


Mich

 

[MvM]

Hi Mich,
Sorry to hear the problem is still not solved. I've had warped heads on a car before and in the end had to dump it because fixing it would have been more expensive than the car's worth. Was an old car though with 200K miles on it.
If you want to work on the car yourself (say, in the evening or over a weekend) I would not mind giving you a hand.

 

[Lud]

Mich - My concern is that, while the car may seem to run fine, if you are getting coolant into your cylinders or oil, that is quite bad for anything that depends on oil as a lubricant (esp. cylinder walls and rings). I would say it is likely that you have at least one of those problems, maybe both.

At the very least please pull your spark plugs and check them. If you see any that are suspiciously clean or that have any white powdery stuff on it, you are absolutely leaking quite a bit of coolant into your cylinders. Plugs that look OK are not a clean bill of health, as the exhaust gas in your coolant clearly indicates a leak, but at least if the plugs are fine the problem may not be TOO bad. Yet.

I know you said you don't think it seriously overheated, but if you have a lot of exhaust gas in your coolant, something is clearly broken. The same thing that lets pressure from the cylinders into your coolant is almost certainly letting coolant into places it ought not be.

 

[Gokwi]

yea, I guess it depends on the situation.. my car over heated while it was idling for like 30 minutes.. but I didn't run it hard while it was over heated.. right now it seems to run like normal, and I still have the same performance I had before.

NSX engines are made of good EXPENSIVE equipment, even though most of it is made of aluminum, they won't give up that fast..

 

[DutchBlackNsx]

@MvM, thankx for the offer, but you will find my car @ TCC, i'm not interested at the moment with doing it myself (yeah, i know.....lazy huh), surely we will go out together with the lads and have a look at the work in progress.

@Lud, Thankx for the input Lud, The worst which can happen at the moment is a 'hydro-lock', which i'm not really afraid of since i'm not really burning coolant, and there is no coolant in my oil, nor is there pressure in my block/heads. If i leave my car overnight, and i remove the coolantcap in the morning, there is still a lot of pressure in the system, which tells me that if there is a leak, it will be very small.
The huge amount of exhaustgases can be explained because i have driven over 3000 miles with it like this

.

Anyway, i will keep you guys posted....


Mmmmm..... might as well throw a cool clutch in.....


Mich