95bowtie

Just thought I'd share my experience. Car is a 2004 gto with factory ls1 cam and head studs only. The rods in these are actually gen 4 style to my surprise. It has around 110k miles now and has been boosted for close to 20k miles now.

1 full summer at 600whp through a 6 speed.

Then 2 full summers at 650-700whp through a th400.

This year I put twin 72 on it and decided to let it eat finally. Ran for a month and a week on 18psi and 15* of timing. We are thinking it was making around 800+whp by the way it out ran cars with 600whp that weight 1k less.

If I were to guess I have 500+ passes on this motor at over 600whp on all of them. I've always beat it like a rental lol.

Onto the pics




I'm not really sure what happened 1st, did the rod or wrist pin start to let go and smack the head?

Thus letting coolant in and the pressure became too high and cracked the sleeve. Or did the sleeve crack from all the power over the years and let the coolant in which then smashed the wrist pin or piston up letting it get all sloppy and over extend into the cylinder head?

Never dealt with this before, I'll know more when I pull the bottom end apart I suppose. May never be able to figure out what came 1st for all I know haha. Either way it's done for.

RonSSNova

iTrader: (3)

I'd say it doesn't owe you a thing!
Sleeves are pretty thin even on the 04 LS1.
A buddy had his sleeved here locally. So you might check into that.
Otherwise go to an iron 5.3, maybe bore to your piston size and re-use all your parts.

slowride

iTrader: (3)

So are the rods press fit or floating? It's a weird deal as the 3.898" pistons they used would have only been used by GM for a very short time with locks, etc. if the rods are like all the other gen 4 rods (bushed for full floating).

What fuel were you running?

DavidBoren

And that is why I am going to start with a 3.78" bore aluminum block. Same outside diameter as the ls1 sleeves, but thicker walls due to a smaller bore.

Not saying that your sleeve failed prematurely. It sounds like it gave you your money's worth. Time to put on the big boy pants and go with something forged in either ERL sleeves or iron.

95bowtie

Have a 2005 lm7 sitting on the floor already!

Payed 150 for it, it has maybe 5k miles on it. Piston tops are clean already when it was pulled.

95bowtie

That I don't know yet about the pins. Haven't pulled it apart yet completely. This may be one of them factory gen 3.5 motors haha. Cameron with the silver crown vic named the LAW found some in a 2004 truck motor I guess. Had gen 4 rods and pressed fit pins.

I've ran e85 the entire time.

slowride

iTrader: (3)

I see, e85 seems to help a lot with combustion temps. I think yours lasted well considering the usage

Dave926

Crazy stuff

Kfxguy

iTrader: (1)

stevieturbo

I'm more amazed it didnt drop valves given there appears to be very obvious piston contact with the valves !!

Pistons look very clean though ? I guess that's the ethanol.

sbcgenII

iTrader: (1)

Kfxguy

iTrader: (1)

truckdoug

iTrader: (25)

last active in july this year. send him a PM he might have email notifications turned on (I think it is by default)

Kfxguy

iTrader: (1)

BCNUL8R

iTrader: (2)

I'm going to guess around 15 psi if he was at 650 to 700 rwhp through a th400. If he had over 500 passes at 600 rwhp and then 2 summers at 650 to 700 I'd say that was pretty reliable and he got his money's worth out of it. I'm at 10 psi and moving up for next spring LOL. I hope it takes 12 or so, but if not oh well it's part of what we do.

95bowtie

just bent the valves a little, replaced with some new used ones and good to go lol. That was the 2nd time i bent valves in those 241s. Now the same heads are kicking on thier 2nd 5.3 motor since this one **** the bed.

Yes e85 only for this motor once I went boost

95bowtie

12psi at 1st with the single 78mm. With the twin 72s I was normally around 16-18psi setting. It seen up to 25 a few times. Think the failure was from overheating the motor a few times tbh. Was having issues a few month before this happened with getting air out of the coolant and I got it hot many times while trying to burp the air out....oh well

side note.....this motor was sprayed before I bought the car as well lol. Then 3 different turbo setups i put it through. Think it was boosted for 4 years before it blew

Kfxguy

iTrader: (1)