#7 piston disintegrated

[Bo White]

Ill do soe horsetrading for the block

[Reaper85]

If he bought it and there was already a tune done to it, it'll usually still come with a x month warranty threw the dealer not threw gm

[Ret Grunt21]

I wouldn’t consider reusing the block. I’ll turn it into a coffee table lol.

[Bo White]

I repair things. Those cylinder heads too. Ill repair them as well.

[InFiD3ViL]

Originally Posted by SS PANTHER

I’m in the same boat. Cats plugged on my supercharged L99 and damaged the ring lands on 7&8. Going forged internals with new cam and valve train. L99 sucks. Powered rods, hypereutectic pistons, nodular iron crank and lousy lifters and valve train. Hindsight is 20-20. If I would have known where I was going I would have bought the ZL1. Good luck with your rebuild.

I'm sorry to be the dick here, but as I am a butthurt L99 owner I feel I have to be. So take this with a grain of salt...

L99 sucks? I am sorry but I do not see anything in your description that shows the L99 to be at fault or contributing to your failure...MAYBE with the exception of the comment about 'lousy lifters and valve train', to which I can fully agree. But based on your description of events, it seems that had nothing to do with your failure.

The reason I take exception to this is that the LS3 is exactly the same setup except for the hollow exhaust valves and crappy AFM lifters (not including cam phaser, AFM cam, lifter valley cover, and any other non-contributing parts to the failure). The LS3 could very well have had the exact type of failure as your L99 did.

Now, if what you mean is that the L99 does not have the brute strength of a fully forged engine, including forged pistons and rods, to be able to take that type of failure - well then of course. But who knows if a fully forged LS3 setup could have handled a plugged cat situation. You could be in the same boat, except out even more money.

But I get what you are saying. Had you known you were going boosted from the beginning you probably would have gone a different route.

You know what? Don't mind me man. I would probably be just as bitter and pissed as you if this happened to me. You hear how these engines can take all sorts of abuse and gobs of power and your engine basically completely disintegrates from the inside due to the blocked cats. Maybe a forged setup could have taken the carnage in stride.

Edit:* Decided to re-read my post then put myself in YOUR shoes.

[christianchevell]

The engine appears to have had some trauma inflicted on it in the past from some forced induction IMO or something going south to cause it to run lean with the rears usually being the pistons that bite it due to FI. Disintegrating pistons even if your tuned when the car was used ;and it just happens to be tuned before and not disclosed and built then returned to stock....with your mild mods should be a case to the dealer you still did not have it caused by your mods in the magnuson moss act......and they are at fault for non disclosure as they took someones problem child that you bought used and they should "fake it" and honor the warranty as you basically did little that could be blamed by any far reach to do this unless you purposefully tuned it crappier than hell to make it lean out and have basically backfires in the rear cylinders blow the pistons apart ..Just stuff IMO.......It was weak when you got it.....a ticking time bomb pre stressed by yes FI or NOS etc.... And your block oh so trashed as a ls3 can only get a .020 over hone and ls7 is only .005 with damn cast in sleeves..a throw away block.

I got my new block from Jerry at SAG performance/custom engine supply off ebay... they stroked and I went forged and the stroke,they clearanced honed assembled and plugged it right etc and the bare block was $1400 of the cost and I got free shipping in the cheaper winter slow season. Cost for mine was about 5k for a 428. Well good luck to you. I know crap happens .....

[SS PANTHER]

Originally Posted by InFiD3ViL

I'm sorry to be the dick here, but as I am a butthurt L99 owner I feel I have to be. So take this with a grain of salt...

L99 sucks? I am sorry but I do not see anything in your description that shows the L99 to be at fault or contributing to your failure...MAYBE with the exception of the comment about 'lousy lifters and valve train', to which I can fully agree. But based on your description of events, it seems that had nothing to do with your failure.

The reason I take exception to this is that the LS3 is exactly the same setup except for the hollow exhaust valves and crappy AFM lifters (not including cam phaser, AFM cam, lifter valley cover, and any other non-contributing parts to the failure). The LS3 could very well have had the exact type of failure as your L99 did.

Now, if what you mean is that the L99 does not have the brute strength of a fully forged engine, including forged pistons and rods, to be able to take that type of failure - well then of course. But who knows if a fully forged LS3 setup could have handled a plugged cat situation. You could be in the same boat, except out even more money.

But I get what you are saying. Had you known you were going boosted from the beginning you probably would have gone a different route.

You know what? Don't mind me man. I would probably be just as bitter and pissed as you if this happened to me. You hear how these engines can take all sorts of abuse and gobs of power and your engine basically completely disintegrates from the inside due to the blocked cats. Maybe a forged setup could have taken the carnage in stride.

Edit:* Decided to re-read my post then put myself in YOUR shoes.

No hard feelings. Yes, I’m irritated as I only had 3k miles on the supercharged motor. And yes, my biggest concern was always the cam and valve train and oil pump, which, I planned to change sooner than later. I was planning on checking the cats 9 months prior, but didn’t get around to it. My fault. The L99, sans the valve train and oil pump, is an adequate motor if it just has the basic bolt ons. For me, I compare this motor to my supercharged 3.4L 4x4 4Runner that I bought brand new 17 years ago with the factory TRD SC and I always gun it, take it 4 wheeling, tow my fish and ski boat and have hauled tons of stuff with it and have 200k miles on it with no problems. This is the first motor that I have blown in 44 years of cars. Drag raced my first car, a 1970 Boss 429 for 3 years. My 1969 Z/28 was a great car, Porsche 911’s, 1970 454 Corvette, and the list is long. I’m irritated and now blame myself for not stepping up to the ZL1 and modifying that. Hindsight. Next will be the trans to go and then the diff. Time for some Preparation H.

[GONIF]

How much boost were you running ? IMHO anything more that 9 pounds will put a hurting on cast pistons if your even the slightest bit lean.

[SS PANTHER]

Originally Posted by GONIF

How much boost were you running ? IMHO anything more that 9 pounds will put a hurting on cast pistons if your even the slightest bit lean.

7.9psi

[GONIF]

Did you data log the car under WOT and full boost B4 it failed ? Running an FI car lean will put a lot of stress on an engine .Perhaps your tune was too aggressive.

[SS PANTHER]

I did not. I had a reputable tuner install and pulley down my SLP TVS2300. I added a MSD BAP and was running the stock LS9 injectors. No internal mods. The car had a custom dyno and the duty cycles and afr were all within safe limits. He kept my rev limiter at the stock 6200, L99. When he pulled the engine out and after the compression check came back low on 7&8, he stores all his tunes for insurance and saw nothing wrong. On further inspection to pinpoint the problem, he found the cats were melted and cracked with a lot of debris falling out of the cats after removal. I drove it hard in the last 3k miles and should have checked the high flow cats.

[SS PANTHER]

I should have stated, that after the compression check, and finding 7&8 low, they recommended pulling the motor. At this time, he found that the ring lands were cracked and further diagnosed everything do find the reason for the failure.

[GONIF]

Looks like a built forged engine is in your future , good luck and enjoy the new more powerful engine.

[SS PANTHER]

Thank you. And yes, going fully forged.