Posted by Johnd [71.246.83.191] on Wednesday, July 30, 2014 at 19:32:26 :
In Reply to: more posted by Gil IN KENTUCKY [139.55.0.133] on Wednesday, July 30, 2014 at 16:24:18 :
Gil,
While the head is off, rotate the engine over slowly and watch all of the valves.. Each one should open and close FULLY. Verify there is some play between the lifter and the valve stem when the valve is closed.
There are only a few reasons for low compression. A compression leak around the piston and cylinder, a leak around the head gasket or block, or the valves.
My bet is the valves, because they were recently worked on, and I guess the engine used to run using the same pistons, rings etc.
See if one or more of the valves are not fully closing, or one or two that might be sticking in the up position.
I suggest the next time you have it together, see if you can start it, even if missing on one or more cylinders. Letting the engine generate some heat and pumping oil thru out the engine can help free up a sticky valve or two.
Flatheads don't like sitting, and rainwater seems to always get into the engine.
Good luck
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