Compression Test

A compression test can give an indication of the health of the engine. Leaky valves or rings might be found by this measurement. My values measured Feb 20, 2003 were 135 psi for the front two cylinders to just above 145 psi for the two rear cylinders. The acceptable range for a street car should be between 130 and 150 psi. They should be within 10 percent of each other. I am not alarmed by the values measured on this engine.

	Spark plug wrench from my old 944. It makes removing the rear plugs very easy.
	Compression tester with the meter, a hose and an adaptor for our spark plug threads.
	Spark plug wrench on the number 3 cylinder. This one is the hardest to remove.
	The adaptor is made of brass. When you remove the hose, it is possible to leave the adaptor screwed into the spark plug. If you drop it, it is nice to have a safety wire around it to fish it out of the shroud. A magnet will not work.
	Testing the number three cylinder. All spark plugs are removed and the throttle is held open. I elected to disconnect the fuel line at the filter to prevent gasoline from feeding the carburetors during the test. The filter is plugged with a golf tee to prevent gasoline from leaking into the engine compartment.

Last modified: Sat, 08 Feb 2003

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