Compression Test Question

[johnny o]

What is the easiest way to go at doing a compression test on these cars? Up top, below anything that can be removed to make it easier etc? I plan on changing the plugs when I do it but just looking for the plugs is fun enough :) Any advice on how to do it or how long it usually takes would be great.

[Bill McNeil]

Johnny,

From what I remember, you have to remove all the spark plugs before you can begin testing each individual cylinder. The compression test kit allows you to screw a brass fitting into the threaded spark plug holes, which tranfers the pressure up a rubber line and displays on a full-sweep gauge. It looks very similar to a fuel pressure tester, actually.

You simply screw the fitting tightly into a spark plug hole until the rubber o-ring is sealing against the head, and then get into the car and turn the motor over as if you are trying to start it. The idea is you want that cylinder to compress about 3 times to get a reading, so you only turn it over for a few seconds. Do this in each cylinder, and record your readings as you go along.

Since you are changing spark plugs anyway, this is an ideal time to do such a test. As for how long it will take you...that all depends on how good you are at threading the tester into each plug hole! When you're finished, just put all the new plugs in, and away you go!

Good luck.

[Kurt K]

I usually pull the fuel pump and EEC relays from under the hood before starting. I usually need a second person to do the driver's side. I lay under the car and start the threads and then the person above twists the hose of the compression tester to screw the fitting into the spark plug hole.