Engine blown - arg!

[toomuchtorque]

Hey guys,

I was driving the car hard for a few minutes, going full throttle for maybe 5 seconds at a time with breaks in between. I was at 4500rpm in third at full throttle when all of a sudden the engine dies. The charging and fuel systems are OK. It turns out that there is no compression (although I dont know in exactly which cylinders), meaning my timing chain, valve stems, maybe pistons, etc. are all damaged.

I'm kinda shocked, to be honest, because the car has only 43k miles on it and I would expect these timing chains to be made to sustain a beating. However, the car is modded and has about 430 rwhp.

My question is, what can I do to make sure that this doesn't happen again, especially considering the extra hp? I read somewhere that I can purchase an LS2 timing chain for the car, which is apparently more durable. Is this true? Are there any good aftermarket timing chains or other parts I should install while the car is being worked on? Are these timing chains notorious for this kind of failure?

This parts and labor are probably going to cost me 4k :W!

Also, heres a list of the mods, if anybody is curious:
MTI Stage 2e heads
MTI X1 Cam
310cc RC Injectors
TPIS Long Tube Headers and X-pipe
Borla Cat Bat Stingers Exhaust
Ported Throttle Body
Haltech Cold Air intake
Professionally tuned at A&A Corvette.
Cross drilled and slotted discs
Steel braided brake lines
14” rear disc upgrade
C6 ZO6 LS7 clutch

Thanks!

 

[Eric Reeves]

Hate to hear this. IMO when you have mods done like you have you are more likely to have something like this happen than when stock. Hopefully its not bad but you will not know the extent until you take it apart. I have beat on my stock LS6 to the tune of 800mi of track time at Pacific Raceways. Never a problem with anything on the car. Again that was a stock car. I understand that the LS2 timing chain is a bit stronger than the stock LS6. Even if the timing chain was not your problem I would upgrade at this point to the LS2 or aftermarket variety. Let us know what you find.

 

[c4c5specialist]

HI there,
Normally, NO the timing chains do NOT fail.
Just a question, was the engine overrevved on a downshift??
Thiswould cause valve to piston contact and a condition your describing.
A cylinder leakdown test would confirm this.
Allthebest, c4c5

 

[TODD L GRIFFITH]

There are 3 things I'd recommend if you have to go deeper into this to save you time if anything happens again. A double row timing chain, 2-piece timing cover and ARP head fasteners, if you don't have any of these already. It's a live and learn type of thing to minimize any pain later on. Hope you can resolve this without too much trouble. Please keep us informed with what you find out.

 

[toomuchtorque]

Thank you for all the advice so far everybody. I will talk to my mechanic about all of these suggestions. The engine is open now and he took some pictures of all the damaged parts (pistons, valve stems, timing chain). I'm upgrading to a double roller timing chain and getting a special damper. I hope this doesn't happen again. I've attached two of them. I'm going to post the rest when I have some more time.

c4c5specialist: I'm 99% sure that the engine was not overrevved on a downshift. However, I may have hit the rev limiter about 10 minutes before this happened.

Also, the mechanic is european, so dont mind his spelling in the pictures

 

[gbik]

In my opinion, the trick is to determine which happened first did bent valve cause chain to break or broken chain leave valve open and get bent?
Actually it doesn't make any difference, just rebuild engine stronger and have fun till something breaks again. This is just an oppurtunity to build the engine better and stronger. Welcome to the world of modified engines and cars. This is why GM tunes engines and systems for reliability AND performance. If your gonna play your gonna pay Jay

 

[gmjunkie]

Just a question, was the engine overrevved on a downshift??
Thiswould cause valve to piston contact and a condition your describing.

After seeing the photos,This would be my guess!!!

 

[toomuchtorque]

I gotta agree with you, gbik - I guess this is what happens when you start messing with a balanced machine.

And no the engine definitely wasn't overrevved on a downshift. I was in third gear the entire time going up and down between maybe 3k and 6k RPM.

Todd - I ended up buying ARP head fasteners and the double roller timing chain. Thanks for the advice.

Here are the rest of the pics that my mechanic took...