Help Pistons have hole in them

[speed8988]

I pulled the head and my concerns were confirmed. I have attached a pic of the piston. This is #3 piston the rest are ok. Here's what concerns me. As you can see the picton is melted from detention I'm assuming but I see no pits on #3 or any other piston. and only #3 is bad. What could it be. Bad Injector, Power Module, Fuel Pump, I was using +40 NEW and a 255 LPH pump. I had a bad AFPR on the car and put the stock back on. I was only running 14 PSI of boost and the motor has only 390 miles on it. How much Boost can a Stock piston hold?



What size of pistons are these?


Here are the numbers on top left to right

Mahle marked under piston Cast #87V90

1807 5131402
M 87.974
0402 SPO.025

Another question is the piston melted and the metal dropped on the rod looks like JB weld. Can I still use this rod?

Quote:

Originally posted by speed8988 Can I still use this piston?

Bwahahahaha.. Oh man, I can't breathe. That's the funniest thing I've read in months.

[speed8988]

Quote:

Originally posted by UnaClocker Bwahahahaha.. Oh man, I can't breathe. That's the funniest thing I've read in months.

I meant Rod.... Naturally I'm not that stupid.

[speed8988]

ttt

[Frank]

try getting a small chizel and with your hand, try chipping that stuff off. dont ding the rod too much. if you can get it all off, you could probably still use it. if you dont, i wouldnt because i would want that stuff to fall into the oil.


frank

DAAAAAAAAAAAAAAYYYYYYYYYYYYYYYYYYYMMMMMMMMMM

that sucks.. looks by the parts numbers they are already .030 over right? and yeah sure use the rod.. how big a "chip" is it?
that M .025 i think means they are .030 over already..
and yeah i get piston and ring combos..

[speed8988]

I think It's .20 over from the 2 the 5 I don't think means anything. Can anyone confirm? That's not a chip it's a melted hole all the way through.

well the pistons are .025 over and the bore is .030 over. normally about .005 difference for casts and around .004-.002 for forged..

[4sfed4]

Quote:

Originally posted by masterjr33-2 well the pistons are .025 over and the bore is .030 over. normally about .005 difference for casts and around .004-.002 for forged..

I think the numbers are reversed in the above?

[shelbyluvinfool]

Well, I'm glad you found out what happened to the motor. Too bad it's just you thought it might be? Is the wife going to let you rebuild it again?

[speed8988]

Quote:

Originally posted by shelbyluvinfool Well, I'm glad you found out what happened to the motor. Too bad it's just you thought it might be? Is the wife going to let you rebuild it again?

She said I can't sell the car until as she puts it "THAT MAN DIES" speaking of Carroll Shelby. She said hopefully once he passes away the cars will go up in value and I can get more for the car. It's really unheard of that a wife says NO you aren't going to sell that piece of Sh*T money pit.

Kevin

[turbovanman]

I would say you went lean. Also, the stock cast pistons can take alot, I have run 26 psi on mine with no incident, and have 23,000 kms on my engine. You just need the proper amount of fuel so as not to melt them.

[TurboChry]

Quote:

well the pistons are .025 over and the bore is .030 over

If a piston is for an overbore, then that is the size stamped on it. Not overbore minus the skirt clearance. Besides , it's still (example) .030" larger than the piston it is replacing. Actually a metric bore would be .75mm (.75/25.4=.0295)over.
How do you know exactly how many miles are on this engine, but you don't know what is in it?
A wire wheel on a grinder and/or a bead blaster will peel that aluminum off of that rod.
Just my 2/100ths of a dollar...don't mean to act like a machinist.

Jim

[speed8988]

Quote:

Originally posted by TurboChry How do you know exactly how many miles are on this engine, but you don't know what is in it? Jim

i know how many miles are on it because it's a re-built motor that I paid to get rebuilt and installed it in my car. I thought there were .020 pistons in the car but the .025 on the piston threw me off. THose piston are indeed .020 from the part number. I'm going to check the bore to see if it's straight. I'm sure it is the machine shop line bores their blocks.

[turbovanman]

Quote:

Originally posted by speed8988 i know how many miles are on it because it's a re-built motor that I paid to get rebuilt and installed it in my car. I thought there were .020 pistons in the car but the .025 on the piston threw me off. THose piston are indeed .020 from the part number. I'm going to check the bore to see if it's straight. I'm sure it is the machine shop line bores their blocks.

Line boring refers to the reboring and straightening of the crank main and cam journals.
If they installed new oversize pistons, they had to rebore the engine or the pistons wouldn't fit! Sorry to nitpit