sirt_eg

Got a ls.vtec engine and the car was running weird. Did a compression test and came out 120/230/230/230. Did a leak down test and the head is fine. Than took the head out and look at the piston and it had a round top edge and not edgy as the other one. Is the piston still good or do I have to get a new one? Also there some damage on it, think the crank is pushing it to high? Look at the top left of the first piston. heres a picture.



The 1 bad pistons?


This the fourth pistons

fireblaze2k1

looks the same from here, you sure it's not the rings?

sirt_eg

Its probably the ring but I was just wondering if I can reuse the piston. By the look of how it is. I wasn't sure if I can resuse it. There is some scratch on the cylinder wall going up and do I need to adjust the valve so it wont hit the piston?

fireblaze2k1

If the valves are not bent, how do you know if the valve is hitting the piston? You should probably get that sylinder rehoned and change out the piston rings.

sirt_eg

there was just some nicks on the piston head. I wasn't sure if the valve was hiting it or not. The head is rebuild already with all motor parts. Going to be taking out the first piston out anyways to look at the ring.

hondamark35

leave no questions in your mind when you get ready to crank it again. take it to a qualified builder/machine shop where they have proper tools and expertise to make everything right. yeah, it costs more than doing it yourself, but you're buying confidence and piece of mind.

Former User

Did the leak down test pinpoint the specific problem? The mentioned scoring of the cylinder wall suggests that air pressure was released into the crankcase. Is this correct, or did air appear elsewhere?

sirt_eg

its the ring. I was wondering can you use usdm p73 piston ring on a jdm p73 piston? Usdm is a a0 and I got the jdm 00.