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Although I can perform a compression test, I am not good at write ups, so I cannot take credit for this. I got this from civic-eg.com this is explained for a single cam honda engine, but for the most part applies to all engines.
Originally posted by teal_dx
This is pretty simple, all you need is a compression tester & ratchet/socket/extension to remove your spark lugs. Do this with the engine WARM.
The small adaptor on the left is not needed for our engines. That piece can contact the piston or valves if used, since it extends into the combustion chamber.
Unplug your spark plugs & label their order if needed.
If your distributor is unmodified, then unplug the dizzy harness. The smaller plug with the 2 thick wires should be all you need to unplug.
I have an external coil, so I just unplugged that to prevent spark.
Remove spark plugs and remember what order you set them in. The plug condition may help you determine the cause of a problem if one of the cyls has low compression.
Insert the threaded hose end into the plug hole & screw it in by twisting the hose clockwise. It should be snug, there's a rubber O-ring on the end for a good seal, so there's no need to crank it down like you would a spark plug.
Once the hose is tight, slide the collar up on the gauge & connect it just like it was a compressor air hose.
Next you can set the compressor down and go turn the key, or have someone else turn the key if you want to watch the needle go up.
Keep the engine cranking enough so that all 4 cycles happen in the cyl you are testing. If you don't crank it long enough, you'll miss the combustion cycle & have a really low reading. You're not going to hurt anything by cranking it too much.
After you're done, put the plugs back in. Connect the plug wires & distributor plug. Start it up & let it run for a min to burn up the gas went in while you were doing the testing.
The small adaptor on the left is not needed for our engines. That piece can contact the piston or valves if used, since it extends into the combustion chamber.
Unplug your spark plugs & label their order if needed.
If your distributor is unmodified, then unplug the dizzy harness. The smaller plug with the 2 thick wires should be all you need to unplug.
I have an external coil, so I just unplugged that to prevent spark.
Remove spark plugs and remember what order you set them in. The plug condition may help you determine the cause of a problem if one of the cyls has low compression.
Insert the threaded hose end into the plug hole & screw it in by twisting the hose clockwise. It should be snug, there's a rubber O-ring on the end for a good seal, so there's no need to crank it down like you would a spark plug.
Once the hose is tight, slide the collar up on the gauge & connect it just like it was a compressor air hose.
Next you can set the compressor down and go turn the key, or have someone else turn the key if you want to watch the needle go up.
Keep the engine cranking enough so that all 4 cycles happen in the cyl you are testing. If you don't crank it long enough, you'll miss the combustion cycle & have a really low reading. You're not going to hurt anything by cranking it too much.
After you're done, put the plugs back in. Connect the plug wires & distributor plug. Start it up & let it run for a min to burn up the gas went in while you were doing the testing.