Piston damage

[aj.hudson]

Im more than likely gonna replace it but is this reuseable?
This would be caused by something foreign in the combustion chamber right? The head has no damage just the piston. And I should be okay just replacing the one or should I buy all 4? Thanks.

[dr.occa]

The piston is actually quite usable. Those gashes can potentially be hot spots and could cause some pinging. As you can see, carbon is already building up in them due to unspent fuel collecting in them just like in the valve reliefs. It would be better to replace that one and clean up the other 3 with some super clean or something. It would be even better to replace all 4 with a box set.

[aj.hudson]

I want to replace it. Price isnt that bad @51$ for piston and pin. Only bad thing is its going to take 8+ weeks to get it!! I plan on rebuilding with forged pistons in a year or so. Think I should risk reusing this one till then? Going to be running all stock maybe poncams later this year driving it daily...

[dr.occa]

Me I would run it factory and save up for the pistons and cams and rebuild with new bearings and cometic headgasket later.

[aj.hudson]

Thanks. Ya I think that's the plan for now then. I'm just going to hone it re ring it and reseal it. I'll save the full rebuild for the "big" build
Should I try and knock the high points down on the gouges or leave it be?

[dr.occa]

Yes, try and soften the edges of those gouges.

[mooreofit]

diddo ^

those pistons are fine from the picture just knock down the sharp edges. if you do not know what caused the damage might want to inspect the piston further.my pistons looked like that in another car and it was a chunk o ring that caused the damage might want to make sure your valves seat fine. as in not bent.

[aj.hudson]

I am going to check everything as I clean it. I got the 20v valve master on the way to disassemble the head. The combustion chamber on the head had no damage. I don't think it's the rings because the bore on that cyl looks ok, but I'll see when the piston comes out. What I think happened is it was run without a filter or open stacks and it sucked in some debris, this makes sense to me because it's the #4 cyl and thats the one thats the first one to see fresh air in a fwd configuration. Does that sound like a probable cause?

[mooreofit]

ahh, if thats the case i would do a leakdown just to check those valves. chances are there is some damage to the seat area when the foreign material entered and exited the chamber.

[aj.hudson]

Damn it! I didn't even think of that!!! The leakdown did fail miserably on all cylinders...but this is what my valves, ports and combustion chamber looked like...

[dr.occa]

Oh yikes man.

I think that motor needs a little bit more attention that we all thought. With the leak down test failure and the crap in the exhaust I think it would be in your best interest to check valves and seats as well as see if the head is still true. New rings and check cylinders for any out of round conditions (I doubt it but check anyway).

[aj.hudson]

Well I found what I hoped not to find!!! Here are the pics.
Ex. Valve seats are hammered intake side seems ok.
It doesn't appear that I'll be needing new valves.
I am hoping a valve job and a resurface and I'll be okay.

[dr.occa]

Hmmm, maybe an opportunity for a 3 angle job?

[daveskatesallday]

*cough* I have a box of brand new pistons lmk

[aj.hudson]

Pmed u^
Well all 4 cyl ex seats look like that...
I thought I could get away without a valve job... Ohwell...

Btw this motor came from jdmenginescorp in Richardson tx. Guaranteed good! Twice!! Compression test passed good running motor...