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.

My machine shop back home would have taken care of that. I don't know who i will trust around here. A couple of locals have given me names. I hate that for you. I am in for pics of bottom too.

I would buy a 99 head and all the aftermarket bits and see If they will do the work for free instead of rebuilding that one. This is assuming they are taking responseabilty for it.

Wow. If a rod actually broke that will be the first M-tuned H beam style rod I will have heard of breaking. Sorry for your loss.

i bet the piston wall clearance was sloppy and that bent a rod wich eventualy broke still im sorry to see another perfectly good motor go to waste. I hope the shop does right by you.

I don't know about the piston wall clearance honestly. I never had any piston slap, so I doubt that was the issue. Maybe, but I doubt it. There is another guy locally who has the exact same setup with the machine work done by the same shop. He had someone else assemble it though. He's never had any issues with piston slap or anything either. At this point I don't know what I'm going to do. We'll see what they say, but worst case scenario I found a decent 60k 94 motor that I'll drop in.

Well.. I pulled the block out today. As I was unbolting the clutch, the motor suddenly decided it would turn again. In it's sudden turn, the thirsty piston popped out of the block to the point where the first ring was above the deck, allowing me to pull the piston out. Here's what I found.

Attachment 193885
Attachment 193886

Not pretty at all. So I get to looking closer. There is one circlip in place, but the other is no where to be found. Not surprising given the damage. I hope I never find it down in the block, meaning it was never there. But I did find some more interesting clues.

Attachment 193887

Those grooves are parallel and exactly the same width as the wrist pin, even though wrist pin is now centered, it had to have come loose at some point. These wrist pins are floating right?

Attachment 193888

Then some more grooves, I'm assuming the one that ultimately resulted in the hole in the sleeve.

Attachment 193889

I also found this... I dont' know what it is or if it's supposed to be there. The little wire looking thingy above the crank. They aren't present in the honda blocks I've rebuilt, and I never saw the inside of this one.

That wire looking thing is the oil squirter. It looks to me like the piston just decided to come apart for no reason, or a wrist pin clip got left out, and it walked. I'd bet on the latter... yes the pins are floating.

I think we have a winner.

Looks like the rods are good.

Soooo, how did those detonation pits happen in your head? Was it like that when you put it on?

I'm hoping the pin walked as well. I honestly have no clue if the head was perfect when I put it back on there. There weren't any glaring signs but I also didn't inspect it with a magnifying glass or anything. Upon closer inspection though, it's not quite as bad looking as the pictures portray. It was dirty in the pics and some of that is from droplets of coolant and oil. There aren't any pits on any of the other cylinders and none on any of the pistons. So if there was some detonation I'm guessing it happened in the last moments of it's life.

looks like they only did one circlip or the shit wasn't seated correctly on install.

Still batting 100% for our Rods.. New batch arrives this week..

Sorry about your loss.. My guess is a weak damaged piston or the clip was missing / loose on the wrist pin.

Nope.. you're rods are still 100%. Even the one that ran into the block and managed to carve a couple notches out of the iron aren't even scathed. I'll have some more pictures of it when we tear the bottom end off and I can get to the bottom of the cylinders but it really is quite amazing. Taking it back to the machine shop on Thursday when I'm out of class for fall break.

still i would get the rods that hit the block checked for cracking it is amazing they held up to block contact like that. i hope the shop does you right.

Regarding H beam rod failiure:

FWIW I googled around for a while and found this really good tech-heavy thread:

http://speedtalk.com/forum/viewtopic...56d1ce84caea98

With this pic: http://i344.photobucket.com/albums/p...2/DSC00996.jpg

H beam rods do indeed apparently fail. From the thread, not from the HP that our motors see though. Also, FWIW I am running M-Tuned rods as well. That came out of a motor that had heavy detonation, nothing piston shattering, but melted shit pistons. The rods were just fine.

Oh don't worry, that one rod will be tested thoroughly before going back into a motor. If I have to take it down to the materials sciences lab and bribe a professor or two, I will. But in the end, it all depends what the shop is going to do. A very likely outcome is them saying there is nothing they will do and I drop a stock motor in the car. And ultimately, this could've happened from manufacturing defects, although unlikely. On top of that, a lawyer and court costs would be more expensive than just replacing the broken parts myself.

Ninja edit: That thread on speedtalk is pretty awesome. I don't think I've ever seen so many really smart people argue about car stuff before.

Well... the machinist basically said "you're screwed"... he swears that this failure was caused by manufacturing defects. Claims he's seen it dozens of times in Mahle manufactured pistons. Apparently they put out batches that were improperly heat treated, making the ductility of the 4032 alloy even lower and they crack or outright fail almost immediately. So my new question... has anyone else seen/heard of/experienced any similar failures with supertech stuff? If that was the case, an entire batch should be bad.

Oh yeah.. and does anyone know who exactly makes Supertech's pistons?

Passing the buck...awesome.

I don't see how even a poorly made forged piston would fail without having seen any boost or det.

Call the manufacturer and see. I would try to get someone to do it. See if you can find that clip. Did they offer to dissassemble?

Piston broke due to improper installation of wrist pin snap ring, period. If it were a piston metallurgy problem, the piston would have broken both skirts. It broke only one, meaning the wrist pin had to have slid to one side ( the side that broke) and during the downward motion tore the skirt off. Again the snap ring was either not installed, or installed improperly.

You could tell the machine shop this all day long, but the fact is, he has the final word unless you persue this legally.

Which if all else fails, you should

Crap it all... pics later of all the fun chunks in the motor.

I'm not going to pursue it legally, either way it turns out, I will be in a deeper financial hole. I never found the snap ring. I asked him to disassemble and see if he could locate it, but he refused. I guess I'm on the hunt for a decent used motor. Oh.. and M-tuned record is slightly tarnished. The rod is bent. Not in a buckling way, the wrist pin and the big end aren't in plane anymore.

Dude, you don't need to invest much at all to pursue it legally. Filing a claim in small claims court is so easy a caveman could do it. (quoting magma here) Just fucking do it.

Don't let that shop fuck you like that, shit.

Iirc, filing a claim in Texas is like $25. It's pointless not to. You never know, you could scare him into something.

Just looked up your county. 184.50

http://www.knoxcounty.org/circuit/forms_civil.php

Made it easy.

Considering Mahle makes most OEM and aftermarket forged pistons (including the ones used in F1's), I'd venture to say it would be correct if he's seen those fail more then others, but that is a wrist pin retainer. They are hell to get in correctly, and even more of a pain to pull out.

After tearing the motor apart today and not finding that clip, I'm starting to think it may not be there at all. It wasn't in the pan, that's for sure. I now have to thoroughly flush out the water jacket just to be sure it isn't in there anywhere. On top of that, I called M-tuned, 949racing, and supertech. 949 said this is only the 3rd or 4th issue they have ever heard of out of supertech pistons, and this one is the only one that wasn't melted. M-tuned said they had seen one other case with similar damage and marks inside the bore and they came to the same conclusion that it was a missing ring clip. Supertech said they have had no complaints of others breaking out of that batch. After all of that evidence, I'm going to see what he says and possibly pursue court.

Good luck.

I would, realizing your location baron. S&G auto machine in Bristol is baller as hell, does great work for cheap.

This shop generally does too... just the few exceptions I've seen.. but I'll definitely look those guys up.

Well.. apparently the shop owner was in a better mood today. After telling him the ring clip was totally missing and that really nobody else had had any problems with the pistons, the owner beat around the bush and didn't exactly admit he did anything wrong, but he's going to help me out. I'm going to buy the replacement piston after he dye tests the others just to make sure they are ok. He said he should be able to straighten the rod too. He's going to do the labor free and sleeve the block for me. All I should have to shell out for is a single piston and a set of rings. Soo.. that solution works for me. We'll see how it turns out.

Might be a good idea to source a used block, but that seams like a better deal than going to court.

Good to hear :bigtu:

It's possible to straighten a rod?!??!?

--Ian

Huh.

I'd at least give Marc a call and see if they can hook you up with one new rod & pin. Not real sure I'd trust a "straightened" rod, regardless how how good it was before the unpleasantness.

And yeah, blocks are not hard to come by and probably a good idea. I don't think I've ever heard of anyone sleeving a BP engine. Your engine guy does realize that this is a sleeveless iron block, right?

Never heard of straightening a rod. Just get a new one, and a new block too. I am getting ready to build my other one or i would offer it up. Also, Gary at classic investments in blountville tn should be able to take care of you for cheap.

Hell.. I have no idea if any of it's actually possible or not. If he can sleeve it though, I'm not worried about that part at all. It's not surprising that you don't hear about it given the general cheapness of the miata community and the same sentiment that it's easier to replace a block than it is to sleeve one cylinder. But on top of that, how many times have you seen damage to only the water jacket and not all the way through the block? I called Marc, he said 1 rod is $150 + shipping while a whole set is only $330. The pistons aren't quite so ridiculous, they are just a little more than 1/4th the cost of a set. It's not the first time I've heard of straightening a rod, given that they are forged steel. As long as they aren't cracked, it isn't a problem, and that's what the dye tests are for. I'm going to look at the budget a little more closely and see if I can swing a new rod and piston just the same. But in the end, I don't think I can afford everything. It's 1 of 3 options:
1. Sleeve block, straighten rod, replace piston (cheapest)
2. Replace rod and piston, sleeve block. (arguably the safest)
3. Replace rod, new block, stock pistons and risk the cylinders being round enough to just brush it and use new rings. Problem with that is actually finding a decent motor. I found a protege motor locally with 93k on it, but it's a junkyard and no history on it.

I dunno.. maybe I will be able to afford all 3, but I doubt it.