I have a 396 stroker, that is supposed to be 11:7:1. How can I check the compression for each cylinder, can someone walk me through this one. Thanks alot!

 

When you do a compression test, you are reading the psi in the cylinder, not the compression ratio. You do it by putting a compression testing guage in the spark plug hole and turning the engine over several times with the throttle wide open.

 

As Bud said, it won't tell you the compression ratio.

Compression test

Engine should be warm.

Remove the pcm bat fuse.

Remove all the plugs. This is so cylinder pressure will only be built up in the one that you are testing.

Remove intake elbow and block the throttle wide open.

Install compression gauge to cylinder to be tested.

Crank engine through 4 compression cycles. The engine will crank a little faster with all the plugs out.

Watch the gauge during each stroke. Normal compression builds up quick and even.

Record readings if you are searching for a bad cylinder and to be able to compare readings. General specs are that the lowest cylinder not be less than 70% of the highest and no cylinder less than 100 psi.

Put everything back to normal when you are done. Be sure you unblock the throttle!

 

Shoebox, should I crank the motor by hand? Should I crank it by key, disconnecting the coil wire so there is no fire?

 

Follow all his directions. You remove the pcm bat fuse so it won't fire or anything. Just follow those directions to a T and you'll be all set :-).

 

Use the starter. It will spin pretty fast with all the plugs out. You will hear it "hit" the cylinder you have the tester in, so you can count the number of revolutions. Removing the pcm batt fuse should kill fire and fuel.