Mikep_86441
NAXJA Forum User
- Location
- AZ
That engine sounds exactly my YJ right before I had to replace the piston. It started sounding like crap on the way home and was blowing smoke out the oil cap. The wrist pin had seized and gouged the cylinder with identical galling on the piston skirt you see in the video. You can see his wrist pin is seized as the rod isn't moving and the rod is discolored. The bad piston was .04 smaller in diameter than the good ones - a badly overheated piston will end up smaller after it cools down. I replaced the piston, honed the hell out of the cylinder wall and all was good for another 30k miles until I sold it.
Funny to note that the factory put half the rings on upside down.
It really sounds like a piston to me too. I am lucky so far that there is no blow by. I just put a quart of Marvel Mystery Oil in to see if that makes any changes. My SO thinks it's quieter. That piston noise in the rear is still prevalent.
I'll do a compression check here soon. Also, as soon as I repair my exhaust analyzer, I'll check to see if the head gasket is leaking combustion gasses into the cooling system.