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Flathead · 01-16-2011, 01:07 PM

A PCV system should have a source of clean air entering the inside of engine and then a PCV valve connected to a central source of engine vacuum. Central being important so that all cylinders receive an even fuel mixture. The idea is to move clean air through the engine, removing blowby gasses and moisture, and keeping the interior of the engine happy and clean. The flow rate of the valve should be matched to the cid of the engine to avoid upsetting the air-fuel ratio. One drawback is that under load, when blowby will be the most, there is little or no manifold vacuum to operate the system. This is when that clean air source is needed to let the crankcase vent out. If a PCV is hooked up to an unvented crankcase it will cause problems as the system can't function properly. I don't think valve deposits are caused by a good PCV. Just something to consider.........

01-16-2011, 01:07 PM	#8
Flathead Senior Member Join Date: May 2010 Location: Southern Maine Posts: 1,696	Re: PCV considerations A PCV system should have a source of clean air entering the inside of engine and then a PCV valve connected to a central source of engine vacuum. Central being important so that all cylinders receive an even fuel mixture. The idea is to move clean air through the engine, removing blowby gasses and moisture, and keeping the interior of the engine happy and clean. The flow rate of the valve should be matched to the cid of the engine to avoid upsetting the air-fuel ratio. One drawback is that under load, when blowby will be the most, there is little or no manifold vacuum to operate the system. This is when that clean air source is needed to let the crankcase vent out. If a PCV is hooked up to an unvented crankcase it will cause problems as the system can't function properly. I don't think valve deposits are caused by a good PCV. Just something to consider.........