Hi I just did a compression test on my 95 diesel pull truck, the truck has different pistons than stock but i dont know what kind, they are suposed to be lower compression. i had an average number of 460psi on each cylinder but #3 was only 400. I squirted oil in each cylinder and every cylinder jumped up to around 520. what are the stock pistons supposed to make? how do I know if mine is ok? and is #3 Bad enough to worry about. thanks!

 

IIRC the book calls for 420 stock... I may be wrong..

 

I heard you wern't supposed to use oil because of the risk of the oil igniting... diesel fuel and oil are very similar.

 

Wow I didnt know about the oil, I have just got in the habbit of doing that with gas engines! thanks for the info

 

Move this into the correct forum. Good luck with your engine.

 

If it runs and starts fine with minimal blowby, I would just run it. Check the valve adjustment maybe.