i got an engine that sat for awhile. the vehicle was wreck from the side. it sit over a year. i had it on the stand and did a compression test and the 2 front passanger side had good readings. 170 both. the other were 120 and one was at 110. i sprayed wd40 and the reads went up to 150 . i still get one on the low side. (rear driver side?)

 

Ahhh good old number 7, check it out carefully. I'd leak test it and scope it. Number 7 is known for broken rings lands broken pistons etc because it runs so much hotter than the other cylinders.

 

Yeah, spraying oil in the cylinder and seeing compression increase is a classic "worn piston rings". Spraying oil in and no improvement either means broken rings or a valve isn't sealing

 

These are low tension rings and you usually don't see wear. Most likely broken from heat or a broken melted worn piston.

 

i did a leak down test and notice it was leaking from the intake valve. i guess when the engine seat for a while the valve seats got little corroded. hope it cleans up after a startup.

 

That's a good thing, better than piston trouble. Maybe fine once its running.