Thirsty Piston
 

So I guess my piston got a little thirsty today. And instead of asking nicely, it decided to go venture out on it's own into the water jacket all kool-aid man style.

Attachment 193973

Then when it got plenty to drink it tried to bang it's way out the top of the motor.

Attachment 193974

And some metal things got in the way, so now my piston has battle scars. Instead of just blowing the headgasket to get a drink of water, it had to get all violent and shit.

Attachment 193975

Now for details and questions: The motor has 336 miles on it since being rebuilt. I took the motor out, took the block to the machine shop along with a box of brand new parts including all the manufacturer paperwork, torque specs etc. I came and picked up the block with the oil pan all sealed up, stuck the head on top of it and went from there. It built oil pressure almost immediately, fired on the first try, and never had any problems. It had some lifter tick, but that was the only 'abnormal' sound in the motor prior to the kool-aid man thing. Is there any way this could possibly be my fault? My reasoning being that the piston is twisted inside the bore. It had to come loose from the crankshaft somehow. Never had low oil pressure, and there was no nasty chunks in the first oil change (at 300 miles). I need theories as to what may have happened. I'm guessing either the rod bolts broke, or came loose, or the rod broke, which I find highly unlikely given that I was still taking it easy after seating the rings. I'm not cracking the pan until I get to the machine shop so that there is no argument that I changed something before it got to them.

fuuuuuuuuu is that as low as the piston goes in the bore? i'd like to see more. hope it works out dat kinda sucks

Dunno.. I cracked the motor, that's where the piston was sitting, about the same height as the number 1, but not exactly the same. I didn't try to turn it in hopes of not damaging anything else.

I'm pretty sure that rod is no longer connected to the crank.

Holy shit! That sucks! Things are definitely no longer connected. Hopefully the machine shop will help you make it right.

Yeah, I see no way this could be your fault, possibly they forgot to torque the bolts, or something, but whatever it was I see no way it could have been you.

Take it up there and have them fix it.

Wow...that's nasty. Total loss.

It's so hard to find a good shop nowadays.

QFT

I hope this ends well in your favor.

What size did they bore it out to? The cylinder wall looks thin in those pics. Could it have been a missing wrist pin retainer? Wrist pin moved out and piston twisted off of rod... Was there a initial pop or bang before the, O YEAH!?

LOLOL

No, there weren't any obviously loud bangs, just lots of clattering, which, in hind sight, was the piston smacking the valves. Then it promptly stopped running. The machine shop I took it to is generally known as doing the best work in the area. It was bored to 84 mm. The only thing I can figure out is that the guy assembled it without really reading the torque instructions for those ARP 2000 rod bolts. I have to finish pulling the block out and take it to them and see what they say, but at this point, I will probably just drop a decent mileage stock motor in it and shoot for 200 HP.

I'm assuming 84mm bore as that's what the piston says. Did they do any testing for structural integrity on the block or just not tighten it up right?

I've rebuilt 5 bp's (3 were the same block) and none of them did anything like that even under mild boost starting at 0km during break in! Good luck with getting retribution you may be in for a battle.

I'd get the head looked at and use that in your claim.

baron, stock or forged rods? Were you boosting yet?

M-tuned rods. No boost yet. I was waiting to install the turbo kit until after FM/Bell's recommended 1000 or so miles.

The machine shop should replace and rebuild at their cost.

Now the real question is will they?

I cannot think of anything it could be, aside from assembly failure. Take the motor back to them, ask them to disassemble it in front of you, and take lots of photos.

I plan to be there and take pictures. The one good thing is that the shop generally does really good work. They also have a really good reputation and the owner is an honest guy that still works there day to day. I don't think they are going to out right try to screw me, but we'll see what they say when they take it apart. I'm praying for a rod nut sitting in the bottom of the pan or a missing circlip. Those are two things that just scream assembly error.

got to be assembly or rod failure. I'd really like to see pics of the bottom end.

The marks on the pistons are from the valves, not any foreign metal floating around. It looks as though it only hit the valves after the initial break. I would be willing to bet the wrist pin retainers weren't installed correctly resulting in the rod coming off the bottom of the piston, then through the cylinder wall, then against something unbreakable resulting in it suddenly stoping.

The shop who built it should take responseabilty, but who know if they will. It is a total loss however you look at it, minus the head which should be fine. Good luck, and I'll be waiting for pics of the bottom end.

Yeah, it's at least a little comforting that the valve marks are twisted like they are proving it collided with the head after the break. The head may be salvageable, but at the very least it needs work. There was some damage done when the piston hit the combustion chamber and I'm betting at least 2 of the valves are fuxored.