compression readings

im curious to know what I should expect from a compression test reading on my flathead. just a ball park idea. thanks. its an adult unrestricted flathead
 
You will have to do a leakdown test. 1-4% your still in the good! You get past 5% in leakdown it’s time to get her freshened up again. You may have to put a wrench on the crank to hold the piston in place and valves shut on the seats while you hit it with air.
 
With the ez start they all seem to show around 65 lbs.
you might get more with an electric starter but you would have had to test when new for any kind of comparison.
Leak down is best .
 
Yep, already replied to your message on this.
Use of low tension rings also prohibit any quality readings from a compression tester at low rpm.
Leak-down is always best - and even then, it still just a comparison. It is best used to identify WHERE you have leakage, ie at a valve or past the rings.


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Brian Carlson
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Vector Cutz
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