Originally Posted by jkas10

I am guessing you are wanting to test for compression.

-Remove the engine from the vehicle and leave the glowplug in and flywheel on - remove exhaust.
-Hold the engine by the flywheel (clutch close to you and exhaust port away from you - crankshaft level with the ground).
-Hold engine with the cooling head up.
-Let the cooling head tip to the side and gravity will try to make the cooling head rotate to the bottom. The pinch/compression will try to oppose gravity.
-If the engine has enough pinch/compression, it should hold the head up for at least 10-15 seconds before the gravity wins and the head rolls to the bottom. If it rolls over sooner, then the engine may start, but will probably flame out as the sleeve expends and compression is reduced.

This is not a very scientific test and results may vary, but it gives you something to go by...