Compression values?

[redneckmba]

I am going to be performing a compression test on a stock 1974 318. The specs say "100 psi, minimum." What should be the compression reading for a healthy 318??

 

[northeast mopar]

Depending on what kind of driving it had which would control the amount of carbon build up you should be in the 140 #to 165# on a compression test( all plugs out and crank for 5 engine revolutions)[QUOTE=redneckmba;1546383]I am going to be performing a compression test on a stock 1974 318. The specs say "100 psi, minimum." What should be the compression reading for a healthy 318??[/QUOTE]

 

[demon seed]

You're also looking for cylinder deviation between the highest and lowest readings which should not, IMO, be more than 10% and most importantly throttle wide open!!!!!!!

So lets say for example you get 7 readings of 150 and the 8th is 130, next you need to pour a little engine oil in the low cylinder and retest. If the pressure comes up you know it's bad rings, if it doesn't the valves or valve seats are bad.

 

[dustertogo]

I am going to be performing a compression test on a stock 1974 318. The specs say "100 psi, minimum." What should be the compression reading for a healthy 318??

Is this engine presenting problems or symptoms? Is there some reason for you to think it's less than "healthy"?

 

[redneckmba]

The engine has a healthy amount of blow by when you look into the valve covers right after running.

Idle quality could improve. It has improved with use of seal sweller and gasoline detergents. One valve seal is could be bad because of oil smoke from one side on hot start-up

I am going to 4 bbl/intake/cam/head this machine. I am a new owner and do not know the history of the car. I want to get an idea of the health of the engine before I do this work. If I need a rebuild, I will do it all at the same time to save work.

THANX for the answers.