what cam is in the motor? if it's got low vacuum at idle, as most performance cams do, then it might not be enough to suck open the PCV valve.

most of those valves are designed to be a "controlled vacuum leak" they have a spring in them that will close the valve under low vacuum conditions, i.e. WOT, so that you don't lean the motor out when you need it the most.

so, verify that the PCV is actually open at idle. Every engine has SOME blow-by on the rings. fact of life. if the PCV is closed at idle, then it has nowhere to go and it WILL vent out the breather on the other side.

you might not have any problem at all! (but my money is on rings! )


a good leakdown tester can be put together prety cheap. harbor freight has them for like, $30. total junk. you need 2 gauges that read on the same scale, and the harbor frieght ones do not.

simple solution. buy a HF unit, and 2 compression testers at the parts store. swap the 2 gauges over to the leakdown tester, and now you have one with 2 gauges that read the same scale.

then you can snag one off and put it back on the comp tester when you want to find your cranking PSI.