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Wiki Stuff-Now titled Compresion stuff

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DNK

DNK

Great Pumpkin
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I want to do a compression test on the *8. Somebody needs to add the procedures for compression testing wet and dry to the Wiki.
Since I don't know what each is that leaves me out.
I know how to undo a plug, screw in tester, turn engine over, read dial. That's it.
Some body tell me what the best procedure is
 
Re: Wiki Stuff

That's basically it; but take all the plugs out first and then do the test.

Sometimes the book says to hold the throttle open, but I've never seen that it makes much difference; since you are only supposed to look at the variation between cylinders rather than the absolute value recorded.

"Wet" refers to repeating the test with a teaspoon or so of oil added to each cylinder as you test it. The idea being that the oil temporarily helps seal the rings, so if you record a much higher compression value, that shows that the rings are leaking as opposed to the valves. But the oil also displaces some of the combustion chamber volume, which also raises the reading somewhat; so it's not always a clear test.
 
Re: Wiki Stuff

As I spin the engine each time (X 8) will the injectors pump fuel into the cylinders?
 
Re: Wiki Stuff

Nope. But if your worried about it unplug the pump. Turn the engine over until the needle on the guage stops rising. Six or seven cycles usually does it.
 
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