orange1500hd

iTrader: (8)

well a few weeks ago i was driving around in the truck, just got the 6.0/80e in, already had the mp70 front mount done. hammered it one last time before i went home and something didn't sound right, let off and it started rattling BAD, engine stalled so i towed it home. number 7 plug looked bad, cracked the piston..pics below. sucks cause this thing is such a blast to drive time for forged pistons

Spoolin

iTrader: (8)

I see the broken piston but I'm having a hard time figuring out what to make of it. Any more pictures?

MikeGyver

iTrader: (5)

??? Yeah, need more pics.

orange1500hd

iTrader: (8)

what else should i take pics of? as far i can tell this was the only damage, i pulled the broke piston/rod out and the one next to it. cylinders look fine but the piston next to it had a broken ring when i pulled it out. little bits of aluminum stuck in the combustion chamber and somehow a few chunks of the slug ended up in the #8 cylinder... as far as the pistons cracking i think i know why. when i pulled the head off the first thing i saw before the piston was the head gasket, the front was on the back im guessing it cut off coolant to the back cylinder. don't know how that got by me but it did and i feel like a real dumbass

MikeGyver

iTrader: (5)

Your picture just has weird lighting or something, maybe if you could change the camera angle, or use macro, it would make more sense to us.

03sierraslt

iTrader: (22)

Maybe I am having a brain lapse but why are the pistons flycut like that? With opposing valve reliefs..

orange1500hd

iTrader: (8)

took some more pics. the pistons are stock lq4 from a 2007 van. they do look different from the ones i have seen.

MikeGyver

iTrader: (5)

So that the intake valve has clearance when the piston is used on either bank. You can't just turn the piston around to use it in the other bank, the mark that designates the front of the piston needs to be at the front on either bank.

MikeGyver

iTrader: (5)

I understand now what I was seeing in the first pic. It was the reflection in the cylinder wall making the piston look much higher in the bore, and the missing part looked like some weird machining mark.

Your mention of the blocked coolant might be getting us closer to an answer for the notorious #7 damage.

orange1500hd

iTrader: (8)

the first pic with the gasket on there is the way it looked when i pulled the head. the gasket is supposed to be reversed, you can see the coolant passages in the gasket that were supposed to be in the back next to #7.