So after investigation of my block, it looks like I blew apart my # 2 cylinder wall. At first I thought it was just a head gasket because of the white smoke... I was not so lucky. So now I'm going to rebuild my original engine, again, and throw in a used 07' LSJ w/6,000 miles on it. This could have been prevented by upgrading the fuel system to a return style system. Two pistons looked about perfect, one piston looked rich, and the #2 piston was lean. I would recomend anyone who plans on doing any serious modification to adress this problem first. What really sucks is I thought I had the tune nailed down. My previous mods were ported head, larger valves, Forged 10:1 pistons, forged rods, ported blower, 2.8 pulley, I/H/E, Dual pass w/ option b. So I guess when I get some money I'll throw it back together, until then I'll be stock

 

You blew with those mods?

 

Yep, cylinder wall destroyed. Imagine a donut with a bite taken out. Thats what the top view of cylinder 2 looked like.

 

I don't think it was not having the return style fuel system which caused your demise. **** I'm running stock rail and lines on my car and it's been holding up finr

 

What else could explain having only one cylinder lean?

 

air distribution.
I dunno I switched intake mani's since I went turbo and all is good now.

 

Interesting... did you go to a custom manifold?

 

I also blew my motor.

Most likely lean too except on cylinder 1, the least common to blow.

Compression is down to 118.

 

I'm running a turbo setup with a Hahn racing intake mani.
stock mani looks pretty crappy casting wise for proper air distribution

 

Does anyone know of an aftermarket manifold for those of us who are staying supercharged?
I did that the first time I blew the motor.

 

i can't be the only one thinking there has to be something way outta wack with his tune to blow his motor on that? or running something else that he's not saying .. cuz a built engine with cooling mods and running a 2.8 pulley i wouldn't think would cause the damage you discribed

 

yeah i really dont think it was the performance mods that failed the motor, i would say it was something more like a fuel injector going bad. You should definitely have those checked out before you put them in your motor again. I know the stock intake manifold flows bad, but i cant see it being bad enough to blow up like it did, you werent making that much HP to really stress the block like that. You really had to have gone super lean to ccause that kind of damage. my buddy blew up his turbo lsj this summer when his electronic boost controller failed, last recorded PSI was near 40 PSI, he cracked the piston wall as well. But that was due to an extreme lean condition.

 

Nope tune was fine, Hours of tuning w/wideband monitoring KR and AFR. It's really not that hard to believe. Higher compression ratio, .020 overbore, slightly longer stroke and 17 lbs of boost, 23 degrees of timing. One piston was lean and thats the one that failed.

Jayson may be correct about the injector

 

well the .020 overbore on the stock sleeves doesnt help, nor the higher cmpression, but still trix's sleeve's held til it spked 38psi

 

There's a new head on ebay for about 300 bucks that could help you.

 

Thanks for the heads up but a new engine is going in on monday. I know it sounds silly but I'm kinda looking forward to having a slow, easy to manage daily driver.

 

Ok got a question? What size injectors were you running OP. 42's or 60's? You didnt say. Driving hard on a 2.8 on 42's could = boom! Even with a tune. There would be your lack of fuel.

 

60's. I have done everything right on this build. This is either a fueling issue or an airflow issue. On a side note, when this happened it was hot outside and I wasn't running meth at the time. So hot air + lean cylinder and a cylinder wall that was weakeneed by the overbore = kaboom. It is possible that when the machine shop ported my head that they were slightly off on the #2 cylinder ports, although i doubt it. When I rebuild this engine I will upgrading the fuel system, getting the injectors flow tested, and trying to solve this manifold problem.

 

If you're tuned for meth and werent running it at the time wouldnt that have made you run pretty lean?

 

shitty deal especially with internal work(ported head, larger valves, Forged 10:1 pistons) ???

 

The tune I was running was not for meth, the afr was safe except for the #2 cylinder.