got this after sitting for 5 years. Had 30 psi when i first tested. changed rings and honed cylinder. all back together and now only have 35 psi. double checked timing and have no idea what to check now. everything looked clean will little wear to valves. any ideas
thanks
Tom

 

Did you actually check bore size, did you check ring gaps in bore to ensure the new ones' gap is below 0.020"? Did you grind the valves in? I assume you have checked valve clearances at TDC on the compression stroke.

 

checked all that and was ok. didn't;t grind valves just checked the gap when i put it back together. i didn't put new valves in

 

OK, so if you know the bore and rings are not leaking, it has to be the valves or head gasket. I would make doubly sure your gauge is working properly. Using the finger on plug hole test probably would result in it not blowing your finger off at 35psi. I don't usually advise a leakdown test as you should have found the reason for low compression by checking things while you had the head and cylinder off, but it may be worth doing one in this case. If a valve is leaking, grind them in, but also check a guide hasn't moved down and stuck a valve open, check carbon build up on stem, this can make a valve stick open. If you can find no reason for the problem, check cam and followers are actually opening the valves fully.

 

having shop check the valves to seat and oil seals. i couldn't tell if valves were sticking but could see them moving when turning over. i don't have the tool to remove valves so i took it to someone else