compression check on a 351W??

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Apr 21, 2009 | 10:34 PM

jdhudall

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From: Minnesota

compression check on a 351W??

I bought a 351W from a salvage yard is there a way to test the compression with out a starter or engine cradle?? I tried to turn it over by hand but only got 40psi for compression on my tester but I don't think that is right because I can't turn it over that fast! I just want to see if it will need a rebuild or not please help!! They claim it was a running engine when it was pulled I hope it will work for me I don't have much money for a rebuild!

Apr 21, 2009 | 10:49 PM

flamebuster

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From: Mattawa Washington.

It can be done, and it will take 4-6 revolutions to build up to an accurate reading.turning by hand is really slow. are you using the starter.?

Apr 21, 2009 | 11:15 PM

jdhudall

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From: Minnesota

no I don't have a starter for it yet is turning it over by hand fast enough to get a accurate reading I turned it over a couple times but not 6 revs I will try turning it over a couple more and see! I just think the slow turning might loose some of the compression while on the compression stroke? but I am no expert that is why I am asking

Apr 21, 2009 | 11:57 PM

greg176

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The only way to do a compression test properly is with the starter.That said you could try doing a leak down test.Google it.That is how small aircraft engines are checked.