PCV with open or closed crankcase?

[HSSS427]

Neverwouldof - I believe almost all engines have some level of blow-by ie the rings don't seal perfectly. I also understand new engines will have higher levels of blow by until rings fully seat, and it's probably also affected by rings, pistons, tolerances, etc. Compression ratio probably also impacts it as well.

Obviously it's not a new issue or situation and you can see that on the original 427s it was addressed with a road draft tube and/or puke tank.

PCV was a pollution control mechanism that kept the vapor inside the engine instead of letting it vent to the atmosphere via straight breather or road tube. My own thought was that using the vacum source of the carb may make the PCV a little more effective since the vacum is drawing the pressure/vapors out of the crankcase vs just relying on the pressure to build up and it gave the vapor some place to go instead of the top of my valve covers!

If you think you're getting too much blow-by, then remember it's a symptom of how well your rings are sealing. Best thing is to then test your rings with a compression and/or leak down test. That will be the best indicator of how well your rings are sealing. If that's normal, then hopefully it's just a matter of getting a crank case ventilation approach that works.

Also, just because your breathers are soaked doesn't mean it's all blow-by. Lots of oil flying around in there and if you don't have a good baffle system, the oil is going to end up in the breather filters. I have a tall "goose-neck" breather on the back of my intake with a steel wool type mesh in the bottom and it was getting lots of oil coming out of it. Someone here at CC pointed out that since I'd gone to a hydraulic cam, there was a lot more oil being flung around in the lifter valley and it was probably contributing to the problem.