I run one on the Olds 350 in my 4x4, fair amount of blow by. I ran one on my 403, put oil on the intake at the track. Never had an issue with my current Olds 350, it has great ring seal which is key.
filtered oil filler cap
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1Bad4558 said:
sure, there were cars in the 60's that had an open system. If you don't have crankcase ventilation that's when you build up condensation and sludge.
pontiacgp said:
That is what PCV is for, to vent the crankcase fumes into the intake to be burned. This also keeps the crankcase closed from the atmosphere and it's humidity.
PCV systems started years ago with road draft systems. In a road draft system, a tube from the upper engine area hangs down near the road. Air moving across the open tube end draws fumes out of the crankcase. That air is replaced by fresh air, typically brought in through coarsely-filtered valve covers 'breathers". At slow speeds of a vehicle did not generate much air flow and therefore less crankcase ventilation. In the 50's and 60's, it wasn't unusual to see oil-burning cars driving along, merrily streaming blue smoke out their below-car breather tubes. They would often have as much bluish-white smoke drifting out from their draft tubes as was streaming out their tailpipes.
Draft tube PCV systems required the vehicle be in motion, and still provided very limited air exchange. The result of such poor air exchange was rapid oil contamination and build-up of hard brownish-colored varnish on engine internals. It was fortunate when a road-draft PCV system car lasted 50,000 miles without burning oil, and most older engines (even with regular oil changes) had varnish inside.
The modern PCV system is a "winning system". The PCV system does not decrease horsepower or economy, while it keeps the environment, engine internal parts, and engine oil clean. The PCV system is very reliable, often lasting a hundred thousand miles or more without maintenance. The only parts to fail are the PCV check valve, hoses, and grommets.
Modern systems commonly use engine vacuum to draw contaminated air into the intake system. These byproducts, rich in hydrocarbons, are mixed with and burned with the regular air and fuel. The typical American V8 evacuation path is out through a one-way PCV valve at the lifter galley rear. The check valve prevents air-gasoline fumes from back-flowing into the crankcase when the engine is stopped, and the valve also acts as a flame arrestor or "backstop" in the event of a backfire. The check valve is usually a small steel ball in a housing, with gravity often forming the "closing spring". This check ball does not regulate pressure, it just blocks any reverse flow.
Gasses (hopefully no oil) are drawn out of the engine through the PCV valve by intake manifold vacuum. This causes a vacuum in the entire crankcase area, including valve covers. To replace gasses lost through the vacuuming, clean filtered air is drawn into the engine through the valve covers. This air normally comes from the regular carburetor or fuel injection system air filter. The regular air filter is a very high quality air filter, much better than older standard breather filters with their coarsely-woven metallic fiber filters used in road draft systems.
Many modern racers use a variation of the old road draft system, using exhaust collector vacuum to pull air out of the engine. Most of these systems don't even provide a filtered air inlet, so they are essentially nothing more than a crankcase pressure vent. Without a clean air inlet, they are one step down from old road-draft PCV systems. Even the crude road draft systems of the 1950's and earlier had filtered air crankcase inlets. Without a clean air inlet, crankcase contaminants are not purged.
Yes, it's fine. I use them on all of my stuff. If you're running a pcv on one valve cover, there needs to be a breather on the other side. Whether its an open oil cap breather or one that connects to the air cleaner as the factory done, it doesn't matter. You don't want a pcv on one side w/o a breather on the other.
Evan's 85 said:
My Buick always had a PCV valve on one side and just a regular oil cap on the other side. Should I have a breather on the other side instead of just a regular oil cap?
joesregalproject said:
No need, there is a line going to the air cleaner that is your breather. PCV will either use the air filer as a PCV filter, or have it's own PCV filter on the side of the air cleaner housing. This is a closed PCV system.
correct, if he still has the factory breather system coming off the air cleaner, he doesn't need another breather.Clone TIE Pilot said:joesregalproject said:
No need, there is a line going to the air cleaner that is your breather. PCV will either use the air filer as a PCV filter, or have it's own PCV filter on the side of the air cleaner housing. This is a closed PCV system.
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