[Jack E/NJ]

I like Henry's suggested experiment. For those who may want to try it, the tube or tubing connecting the crankcase opening (oil filler opening on my 21-studder) to the air filter cannister should be comparable in size to the road vent. The tubing connection at the air filter cannister should also be made as perpendicular as possible to the intake airflow to also take advantage of bernoulli dynamics. In my situation, this setup has virtually eliminated those nasty crankcase fumes that somehow find their way inside the car from the road draft tube or the oil filler cap when the car isn't moving very fast.

Jack E/NJ