Intermittent crankcase pressure issues

As for the leakdown, the test ought to be done with the engine rotated and then stopped so that the piston in the cylinder under test is on the upstroke, to simulate the ring positions on the power downstroke. That might explain the changes in the leakdown results.

Rings installed with the 'dots' up? Top rings gapped per the KB instructions?
Where is the PCV valve hooked up to? Sure it is directly into the intake? What kind of RPM range are you running?

Going back to your #1 post, I am trying to think how the bent exhaust pushrods would cause these same symptoms....

I'd seriously run the test with the low pressure gauge like AJ described. You can use a simple vacuum/fuel pump pressure gauge. That will give you some direct numbers on the crankcase pressure for evaluation. (You can tell if it is really gross blowby by putting you hand over the open breather hole at idle..... there ought to be very little or nothing blowing out. But that can be subjective.)

BTW, that hill climb sounds fun... where was it?

33W leaving out of Harrisonburg towards WV


The bent pushrods came from my rocker shaft being on the wrong way. This probably starved the valvetrain and caused the exhaust valves to stick and that was causing some issues with blowby.

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Bent Pushrods on a rebuilt 318