The Stovebolt Site Forums The Shop Area Engine Shop PCV valves, band aide?

I've been reading different takes on installing a pcv valve on a Stovebolt 6. I've read that it was first designed during WWII for tanks to keep water out of engine draft tubes and to help keep engine oil cleaner. Then in the early 60's it became a required item for the left coast as a polution control device. Fast forward, are people using it as a band aide for 60+ year old engines that are in need of some internal tlc? I'm not saying it's wrong to use one, I just don't think it's a tah dah moment in the evolution of our prized power plant.
Ok guys that's my take. Don

Good point Don. The PCV valve will never keep up with the contamination from excessive blow-by of a well worn engine. If you have milky oil under the valve cover and dripping out of the road draft tube, you need new rings and or pistons, or you need to drive it on the highway more often and cook the water out of the oil. Still likely a good idea for a fresh engine.
Carl

The most noticeable advantage of the PCV system is approximately double mileage between rebuilds. A clean air intake for the crankcase vent system keeps dust out of the oil and gives a noticeable reduction of abrasive wear to piston rings and bearings. It won't fix a worn out engine, but if positive ventilation is incorporated into an overhaul, the next one will be a long time coming. I was involved in hundreds of PCV conversions of California cars in the mid-1970's when it became a requirement for registration of pre-1968 vehicles.
Jerry

You would probably need a closed system PVC set up to gain that advantage on rebuilds? Jerry.

John

I always plumb the PCV to draw the input air from the "clean" side of the air filter. The horsehair "filter" in the vented fill cap strains out rocks, marbles, and bowling balls and lets dust go right through!
Jerry

The best way to create good circulation of air through the entire engine is to draw air out of the former road draft tube position with the PCV valve, and input air into the valve cover by plumbing air from the filtered side of the air cleaner. That introduces air into the valve cover, draws it down through the pushrod cover, and completes the circuit by sucking up whatever blowby gases are present around the crankshaft and rods. All the gases and vapors are then drawn through the PCV valve into the intake manifold and burned along with the fuel mixture. It's a totally clean setup that does not allow any dust or dirt to get ingested into the crankcase. Later-model engines use a hose from the small separate filter unit in the side of the air cleaner housing to supply the air to the valve cover. Either method supplies clean air for crankcase ventilation.
Jerry

Looking at Tim's page above, the '54 version would be superior to the much newer design, in terms of providing clean air for the PCV system. In the '54 design, the air is drawn from the filtered side (center of air cleaner), whereas the more modern versions pull unfiltered air from the side of the air cleaner.
Carl