lost a piece of piston...Stumped?

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H

HOOCH

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Well just got done tearing apart my motor, car was running a lil rough so we went in for a valve adjust. Pulled the plugs and found one that was smashed :banghead: so i decided to pull the heads to make sure nothing funny was going on inside. And this is what i found
View attachment photo (5).jpg

and the piece was nowhere to be found, also could only find a few tiny lil , marks on the head. Anybody have any thoughts on what might have caused it?

Also i have to ask how in the heck am i supposed to remove the headers? I have heddmen on there and i cannot get them out even with the heads pulled off...:banghead:

Info:
67 Dart GT
4spd
360
J-heads
 
Is it my imagination, or does that piston look awfully loose in the bore?
 
im no master mech, but its at my buddys shop and he is just helping me do the work. he didnt think anything else looked out of the ordinary. But once we get the motor pulled we will be checking all the specs.

What is the correct ring gap supposed to be within?

No nitrous just a mild build 360
 
that looks like there is way way too much room between piston and bore. Check if there is odd wear paterns on bore when you remove piston.
 
Shoot, I've lost a complete piston, Rod, cylinder wall & a valve in one whack. They disappeared into thin air. I found pieces of parts in the carb! After I put the new motor in and fired it off, there were pieces and schrapnel flying out the exhaust... A lot of it was caught in the mufflers.
 
just remember ...your piston clearance is at your skirts not at the top of the piston...
 
I'm thinking maybe instead of it being a part of the piston, it's something the motor ate that disagreed with it. Unless the piston is burned, usual damage is to the skirt and the pieces wind up in the oil pan or the oil pump pickup screen.

General rule of thumb is .004 inch of ring gap for every inch of bore. However, that is for a cast piston. A hyper and a forged piston may have different recommended gaps. See the piston manufacturer for recommendations.

The piston shown is not a stock 360 piston. The stock 360 pistons that I've seen are actually dished. This piston has a dome. Could it be a KB107? There were some guys posting last spring that said they had problems with the KB107. Use the search function to find them.

Typically a forged piston is going to be a little loose in the bore due to thermal expansion. This is part of why a Hemi sounds like a coffee can full of rocks til it gets warmed up. I don't know enough about this engine to say it it was bored out and the wrong piston was installed. The piston looks a little loose, even for a forged piston. I don't see a ridge, which tells me the engine work is relatively recent.
 
Common on hyper pistons with standard ring gapping. Top ring locks up and breaks off the ring land.
 
Tragic and sickening,I feel for ya brother...now you must go thru the whole thing just to make sure everything else is alright...
 
Sorry for your loss. I can't help with the piston, but I just pulled my crappy headers off recently. They'll come out after you get the engine about two feet off of the ground. Don't forget you have to disconnect the steering for it to slide out of the driver's side also.
 
HOOCH said:
Well just got done tearing apart my motor, car was running a lil rough so we went in for a valve adjust. Pulled the plugs and found one that was smashed :banghead: so i decided to pull the heads to make sure nothing funny was going on inside. And this is what i found
View attachment 1714679400

and the piece was nowhere to be found, also could only find a few tiny lil , marks on the head. Anybody have any thoughts on what might have caused it?

Also i have to ask how in the heck am i supposed to remove the headers? I have heddmen on there and i cannot get them out even with the heads pulled off...:banghead:

Info:
67 Dart GT
4spd
360
J-heads
Click to expand...

As somebody has already stated-The pieces are long gone. Those look like KB 190's and are hypereutectic. If the rings were butting then yes this will happen although I doubt that is what happened. What you experienced is detonation. I have done this very thing myself. I bet your fuel quality was insufficient with that solid dome. No biggie--I wouldn't blame the piston either, hypereutectics when employed properly will last a long time. You will need to measure some things and get your static compression ratio figured out. People here can help. J.Rob
 
Man thanks for all the insight form everyone. Should have the motor pulled today and will check the numbers on the piston when I get pulled. Everyone's got me all worried with bore and such being wrong :( I hope not cause since I bought the car it's just been finding one thing after another. Guess if I have to go that deep and rebuild it I might just go with a stroker kit!?

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Seen the same thing happen on a 6.2 gm ls motor in a Cadillac escallade. It came into my friend Pete's shop and he wanted my opinion on what may have caused the damage. On that motor the peice of ringland destroyed the quench area of the cylinder head. I agree with RAMM about detonation being a possible cause. I believe the Cadillac piston failed from a clogged fuel injector making that cylinder run lean and detonate.
 
My kb hyper pistons in my 318 broke the top ring lands off just like that as a result of pinging from too much advance when my distributor wasn't held down properly.
 
Well seeing as I'm going to prolly need new pistons, what's the right piston to go with without breaking the bank? Just looking to mainly street with the car

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Mad Dart said:
Shoot, I've lost a complete piston, Rod, cylinder wall & a valve in one whack. They disappeared into thin air. I found pieces of parts in the carb! After I put the new motor in and fired it off, there were pieces and schrapnel flying out the exhaust... A lot of it was caught in the mufflers.
Click to expand...

Drag racing guy I used to help would lose parts every now and then. Was running a set of aluminum rods once, had a failure. Took it apart and one rod/piston was pretty much gone. Head needed to be welded up...found parts stuffed into the karbanators....found about 1/2 of the piston/rod. Always amazed at what can happen when things go wrong.....Good Luck.....
 
for new piston we need to know what you wanna do with the engine
I ran KB piston for almost 10 years even with nitrous
without any problem.need to check ring end gap carefully

or take a look on ebag there is a few company who's selling piston there
 
HOOCH said:
Well seeing as I'm going to prolly need new pistons, what's the right piston to go with without breaking the bank? Just looking to mainly street with the car

Posted via Topify using iPhone/iPad
Click to expand...

If in fact they are the wrong size, then a whole set will be nec. but if it's only the one or two,, right sized pistons,, then single pistons can be purchased..
 
inertia said:
Don't be surprised if you find a chunk/chunks in another cyl,, I have..
Click to expand...

Both heads are off and everything else looks good that I can see. The motor is only supposed to have around 2000 miles on it. But who knows? The guy I bought it from lied about the floor pans, and the quarter panels. Be the last time I trust buying from a distance again

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