Compression Check?

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Couper

Well-known member
RRR Supportor
Joined
Aug 26, 2020
Messages
1,381
Location
Northern NJ
Thought I'd throw this here as well. In working on clocking my oil pump tang / intermediate gear I needed to put my #1 cly in the compression mode. Since you really can't get your finger in the spark plug hole I used a compression tester.

Screwed it in and turned the crank using a breaker bar... seems I get a slight huff but no reading on the compression gauge....well about 12psi.

This motor was built 3 years or so ago. Shouldn't I show a reading?

Am I ruining anything by turning the crank like this without priming oil? I probally turned it for 10 revolutions....

Thanks....
 
I have never done a compression test without actually cracking the engine and throttle open all plugs out. I have heard of people putting a scrap of paper towel over the hole and when it blows off it is at the top stroke. Jim
 
From what I'm hearing....I won't show a good pressure cranking by hand. And most importantly they say I haven't ruined anything. Now to figure out the proper location of the damper for oil priming
 

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