Catastrophic engine failure, suspect pre-ignition (Pics to follow)

[DoctorDex]

One thing I'd like to get peoples opinion on: How should I go about attacking this problem given the smashed spark plug? Should I be pulling heads first or should I be dropping the pan, because its easier?

[Dj4play]

Originally Posted by DoctorDex

One thing I'd like to get peoples opinion on: How should I go about attacking this problem given the smashed spark plug? Should I be pulling heads first or should I be dropping the pan, because its easier?

Ok. well what happened was you broke a ring land on your piston. I would venture to say 4 and 6 are the usual ones to go. Go ahead and pull the motor. The heads has debris stuck in it with some bent valves and your bottom end has at least one broken piston.

[1stStealthN/A]

Originally Posted by Dj4play

Ok. well what happened was you broke a ring land on your piston. I would venture to say 4 and 6 are the usual ones to go. Go ahead and pull the motor. The heads has debris stuck in it with some bent valves and your bottom end has at least one broken piston.

I agree, pull the motor.
I bought a 92 Stealth TT at an auction that smoked so bad you saw nothing behind the car. A police officer actually followed me for 5 miles on the way home and didn't stop me.

The first thing I did was check the plugs and do a compression check. All cylinders were 155 except #2 which was 30.

Number 2 spark plug looked exactly like yours and the two middle ring lands on the piston were destroyed, plus the cylinder is screwed up.

On this car the kid didn't monitor knock or anything else but installed a MBC and wired the wastegates shut. The two middle main bearings were down to the copper also.

You a have a really nice car, fix it right with forged pistons and don't get cheap on any internal parts.

Good luck

[AdamVR4]

Stock parts should be good enough for any power you make with that mod list. Use quality stock parts and spend a little extra to ensure a high level of machining precision.

The first rebuild has a high probability of failure, so it's not particularly wise to go crazy on internal parts.

New short blocks are cheap, and Ray Pampena (now Scott Merkel) sell some VERY reasonably priced staged upgrade blocks. IPS does too. Since time is a major issue for you, I'd highly recommend buying an assembled short block from Merkel or IPS. Peace of mind, time efficient, well priced... Why fuck around with machine shops that all seem to suck balls?

Sorry to hear about the failure. That would be a really frustrating way for an engine to go out. I'm very grateful that I've never experienced something like that in my car or any car I've tuned. How much faith did you have in the knock sensor?

[Dj4play]

Originally Posted by AdamVR4

Stock parts should be good enough for any power you make with that mod list. Use quality stock parts and spend a little extra to ensure a high level of machining precision.

The first rebuild has a high probability of failure, so it's not particularly wise to go crazy on internal parts.

New short blocks are cheap, and Ray Pampena (now Scott Merkel) sell some VERY reasonably priced staged upgrade blocks. IPS does too. Since time is a major issue for you, I'd highly recommend buying an assembled short block from Merkel or IPS. Peace of mind, time efficient, well priced... Why fuck around with machine shops that all seem to suck balls?

Sorry to hear about the failure. That would be a really frustrating way for an engine to go out. I'm very grateful that I've never experienced something like that in my car or any car I've tuned. How much faith did you have in the knock sensor?

i agree to a point. but anyone who resbuilds a motor without forged piston is a retard. The factory rods are fine to 600 hp wheel

[donniekak]

Originally Posted by Dj4play

i agree to a point. but anyone who resbuilds a motor without forged piston is a retard. The factory rods are fine to 600 hp wheel

From your grammer and syntax I take it you have built motors with cast pistons then. No need to rip on people, stock rebuilds are fine.

[darkkiller]

dude that sucks big time man. good luck with the build, i hope nothing like this happens to my motor. 196K on it now and running 25psi with 16Gs and 100% meth

[Dj4play]

Originally Posted by donniekak

From your grammer and syntax I take it you have built motors with cast pistons then. No need to rip on people, stock rebuilds are fine.

not ripping on ppl. just my rude way of getting my point accross. Few a few hundred more, someone can put in a set of lesser expensive forged pistons. Pistons in a 6g72 are the weakest link. Makes no sense to have everything apart and not replace them

[DoctorDex]

So, from what you guys are saying I'm going to pretty much need new/used/rebuilt shortblock & head work (at the very least)?

I would absolutely love to get a Merkel/Pampena shortblock with forged pistons + some DR stage 3 heads, but at the moment I just don't have the cash. I think I'm just going to have to settle for a used (25K miles) 4 bolt longblock (with DR stage2 heads).

There are a few other things that need to also be done while the engine is out which are going to seriously add to the cost of this rebuild:
1. Send transaxle to Kormex to have them fix the excessive transaxle backlash + strange rubbing noises in my tranny.
2. ? Bell housing reinforcement
3. New clutch capable of taking a beating. Considering the RPS 6 puck with sprung hub. At the moment I have DR650R's with a centerforce dual friction setup, but have plans to upgrade to either Evo3-16g's or DR800/1000 kit in the next summer if everything goes well with this rebuild/engine swap.
4. 120K service. At the moment my car has 100K on it, but might as well do it a bit early and start as fresh as possible.
5. Buy beater to get me around for the next year.

A few dumb questions for you guys:
1. Is it possible to swap out the stock pistons without having to do a full shortblock rebuild? Could I just take a used shortblock (in good working order) to any old machine shop and have them swap in some forged pistons without paying outlandish sums of money? Or is this just asking for trouble?

2.Are the 2nd gen pistons any stronger than the 1st gens? I know they are both cast, but are they the same part number?

AdamVR4: It appears I put too much faith in the knock sensor. I'm assuming a broken ring land points towards knock induced damage? Its too bad I can't change the title of the thread.

[AdamVR4]

Originally Posted by Dj4play

not ripping on ppl. just my rude way of getting my point accross. Few a few hundred more, someone can put in a set of lesser expensive forged pistons. Pistons in a 6g72 are the weakest link. Makes no sense to have everything apart and not replace them

So, what forged pistons can you find for anywhere near $300? Stock pistons can be had for essentially free. Stock pistons are fine if you keep the A:F rich, even well above 600 AWHP... Which he won't ever sniff with those turbos.

The only reason one might conclude that stock pistons are the weak link is because they keep cracking them in people's cars. My stock pistons are fine. I expect my stock rods to fail due to fatigue before the stock pistons. Freak failures and tuning accidents claim the lives of our stock pistons... Not pure, clean combustion. At least, I've yet to see a true example suggesting otherwise.

He only has DR650's, stock pistons are fine. If he wants to spend some money, he should buy an assembled block at whatever stage he wants from one of the proven reliable engine builders (Merkel, IPS) or he should just get a new OEM shorty. I think Merkel was selling assembled shorties with forged pistons for the same price as new OEM blocks. That's pretty reasonable pricing.