Compression question
Thread Starter
Drifting
Joined: Sep 2000
Posts: 1,355
Likes: 0
From: Germantown Maryland
Compression question
When I measure the compression of all 8 cylinders on a 350 I get all 140s PSI on one side and on the other side in order I get 145, 130, 120, 120 . Is this enough of a variation to worry about?
I know I can determine if its valves or cylinders by squirting oil in and testing again.
I know I can determine if its valves or cylinders by squirting oil in and testing again.
Burning Brakes
Joined: Apr 2001
Posts: 752
Likes: 1
From: Springfield Oregon
Re: Compression question (Clink69)
I've always been told that there should be no more than 10% difference between the highest and lowest readings. Was your motor fully warmed up and your carb open all the way? If so, I'd say those 120's are a little suspect, but not too far out of the realm. Hopefully someone with a little more knowledge can expand on this a bit. Good luck.
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Re: Compression question (Clink69)
Make sure your battery is up to the job for the compression test.
If it's weak it will give you incorrect readings.
How many compression strokes are you counting for each cylinder?
If it's weak it will give you incorrect readings.
How many compression strokes are you counting for each cylinder?
