How much boost, and were you running meth? 
Too much boost and valve float?
Thread Starter
Safety Car
Joined: Mar 1999
Posts: 3,611
Likes: 182
From: Toronto, Canada
Melting Slicks
Joined: Feb 2006
Posts: 2,184
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Race Director
Joined: Nov 2001
Posts: 18,682
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St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12
Guys I ran 15lbs of boost on stock bottom for 2+ years making over 700rwhp. I did not baby my car either. There are videos of my car bouncing off of limiter like no tomorrow. I did run Alky, tons of Torco and LS2 timing chain along with all valve train upgrades including hardened pushrods, lifters, oil pump, LS2 chain etc etc...
Stock block was still in perfect condition when it got swapped with forged one. I would just say he had a faulty timing chain
Stock block was still in perfect condition when it got swapped with forged one. I would just say he had a faulty timing chain
Safety Car
Joined: Apr 2000
Posts: 4,326
Likes: 140
From: Weatherford, TX
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Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
I had the same problem with my motor without the broken chain. Just the head of the valve snapped off. Retainer, locks and spring still intact. None of the other pistons had valve marks. I had dual springs on my setup. I spoke with a few engine builders and tuners at the time that said they've seen this happen from time to time and figured it was just fatigue on the hollow valve. I put solid stem valves in my new heads so I don't have this happen again. I was only running 10psi on a forged motor built by Lingenfelter. I don't blame anybody but Murphy.
Former Vendor
Joined: Mar 2008
Posts: 2,279
Likes: 1
No detonation, the plugs would show colour and so would the bearings. The hollow stem valves breaking is a common issue with the LS6 heads. Not too mention the cam sprockets not being tight on the 04 cars.
If it was detonation, the piston would have a been in pieces.
Lot's of people have run and been running over 12-14psi on a stock shorts-remember boost is just a measure of restriction and with stock heads and cam the boost numbers are easy to inflate.
My stock shortblock from 06 is still around doing fine and is going to get blown again very soon. It's all in the tune.
It let go cause it just decided to let go-boost is not the issue. It was probably the end play in the chain-that's why GM put the mounting bosses for GMPP chain dampner on the LS6 blocks.
If it was detonation, the piston would have a been in pieces.
Lot's of people have run and been running over 12-14psi on a stock shorts-remember boost is just a measure of restriction and with stock heads and cam the boost numbers are easy to inflate.
My stock shortblock from 06 is still around doing fine and is going to get blown again very soon. It's all in the tune.
It let go cause it just decided to let go-boost is not the issue. It was probably the end play in the chain-that's why GM put the mounting bosses for GMPP chain dampner on the LS6 blocks.
Instructor
Joined: Apr 2002
Posts: 148
Likes: 0
From: toronto ontario
I don't think you guys are looking at this the right way, my take on this is that the valves were floating with stock springs then the valve made major contact with the piston. When the valve dropped it got lodged in between the piston and the head hense this is why the piston is all caved in in one spot so the engine tried to stop dead and the stock chain won't take that, hell a double chain wouldn't take it!!!!!!! Good luck with your new build.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
I don't think you guys are looking at this the right way, my take on this is that the valves were floating with stock springs then the valve made major contact with the piston. When the valve dropped it got lodged in between the piston and the head hense this is why the piston is all caved in in one spot so the engine tried to stop dead and the stock chain won't take that, hell a double chain wouldn't take it!!!!!!! Good luck with your new build.
Instructor
Joined: Apr 2002
Posts: 148
Likes: 0
From: toronto ontario
If that's the case, then there would be signs of at least light contact on the other pistons. There is way too much force for a valve, turned sideways in the combustion area with an aluminum piston and cylinder head would even come close to dead stopping an engine. Besides, how does "dead stopping" an engine via smashing a valve between the combustion chamber and piston, which is driven by the crank, put any pressure on the timing chain. Anyone that has hydraulicly locked up a motor would have experienced a timing chain breakage event. That's like saying the tail wags the dog.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
I missed the part where all of the pistons were kissed, but where you're losing me was the mention of the motor dead stopping causing the chain to break.
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
13psi of boost on stock LS6 valve springs= valve float, piston hit valve, hallow valve broke=kaboom...
The 04's came with the newer beefer LS2 timing chains, at least my 04' did so I doubt the chain broke first..
The 04's came with the newer beefer LS2 timing chains, at least my 04' did so I doubt the chain broke first..
Thread Starter
Safety Car
Joined: Mar 1999
Posts: 3,611
Likes: 182
From: Toronto, Canada
Guys I ran 15lbs of boost on stock bottom for 2+ years making over 700rwhp. I did not baby my car either. There are videos of my car bouncing off of limiter like no tomorrow. I did run Alky, tons of Torco and LS2 timing chain along with all valve train upgrades including hardened pushrods, lifters, oil pump, LS2 chain etc etc...
Stock block was still in perfect condition when it got swapped with forged one. I would just say he had a faulty timing chain
Stock block was still in perfect condition when it got swapped with forged one. I would just say he had a faulty timing chain
