First thing to look for in a compression test is that all the cylinders are more or less equal. I think I saw where You say the motor was previously in a boat which means it was ran at wide open throttle with all the oil going to the back of the engine as the prow was out of the water. That condition would starve the front of the engine for oil and the parts in front will be worn more than the parts in the back of the engine. That also would explain the smoke, you have some rings worn out. Where there is smoke there is oil or coolant which will foul the plugs and make it run bad. It's time to take the engine apart and see what you have to work with. Everybody on here can give you guesses and opinions as I have just done but you will never know until you take the engine apart. You have been asking for a year and still don't hear an answer that you want to hear?
Originally Posted by mswilkes65Chevy
I finally did a compression test today. this is an inline 6 250 from a chevy c20. The compresion is as follows from the front of the motor to the firewal.... 130,130,120,120,110,90.

i then put some oil in the first spark plug hole and the compression went to 180.

My question is could these obvious bad rings cause all the symptonms listed above. I plan on doing a complete rebuild to cover any possible issues, but i am curious if this would cause all that.


thanks....... i think

Last edited by FriedGreenTmater; 03/11/2010 5:20 AM.
1953 Chevrolet 3600
Fried Green T'mater (Vern)
In the Stovebolt Gallery
Caution: Political Statement
Man who runs in front of car gets tired, man who runs behind car gets exhausted.