Never heard of that one. I used to do it alone with a remote starter button, no throttle used.
Compression Test: Warm engine first?
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Racer
Joined: Nov 2005
Posts: 340
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From: Dublin
Compression Test: Warm engine first?
Was reading an operation manual for a compression tester that harbour freight sell, its says to warm the engine to normal operating temp before removing the plugs! This necessary? Would like to avoid removing the plugs beside roasting headers. Havnt heard this before, is the manual correct? Must you put your foot on the gas pedal too?
Connect the Compression Tester to the first cylinder of the engine. With the fuel
pedal depressed all the way down, crank the engine for at least eight revolutions.
Connect the Compression Tester to the first cylinder of the engine. With the fuel
pedal depressed all the way down, crank the engine for at least eight revolutions.
Last edited by briaineo; Jul 8, 2010 at 06:19 AM.
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Yep, that's the way to do it.
If you're concerned about having a bad valve or broken rings on one or two cylinders you could do a cold test. Compare the numbers on all cylinders and see if any are out of range.
The warm test is better if you're concerned about normal wear.
If you're concerned about having a bad valve or broken rings on one or two cylinders you could do a cold test. Compare the numbers on all cylinders and see if any are out of range.
The warm test is better if you're concerned about normal wear.
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The purpose of a compression check is to compare the numbers between all the cylinders. Any that deviates from the rest indicates a problem. The actual number itself is rather meaningless since different cam specs and profiles will drastically change the readings. So, warmup is not necessary, nor is holding the throttle open. Just check all cylinders under the same conditions and it'll give you the information you're looking for.
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