okay i just check my compression and it was (1-4) 210 130 210 190, as you can see, the 2nd cylinder is way low compare to the other ones. i tried adding oil in the spark plug hole and it jump up to 150, what do you guys think, is it piston rings, my car is still running very powerful though. also, would it be okay if i just grab a piston that still has ring intact with it and just replace it with my piston, would that be okay without no hone or is there something that is require when installing piston.

 

its def the piston rings... one way or another those rings arent doing their job, just my 2 cents

 

that's what i'm leaning toward too, but i'm gonna be doing a leak down test this weekend, do you think it'll be okay if i just slap on a used piston with piston rings without doing any work to the block?

 

noooooo.... just rebuild it if your gonna do that other wise leave it alone it might get worse my 2cents.

 

well my brother did it like that to his 240sx and compression came back up fine and his car is running fine now.