I like to pull clean air in only one valve cover so it can have a better chance of pulling crankcase vacuum and getting fumes out hence the name POSITIVE crankcase ventilation.
I'm glad this came up. The 455 engine I had built has no PCV valve and breathers in both valve covers. Everyone keeps telling me to convert it back to the PCV system. I'm running a B4B intake with the PCV port plugged. If I convert it back to a PCV I just need to make sure I have the valve, grommet, hose and a bathtub manifold gasket....right? Will I be safe running the same valve covers with breathers in both sides or does one of the holes need to be closed off? Appreciate the info!
For what it's worth I hooked up the PCV on the Electra to the corresponding port on the Sniper to the one used on the Quadrajet it replaced. (Edited to fix images) I have one valve cover breather on the drivers side. Original Quadrajet - PCV uses large diameter blue vacuum hose And with the Sniper Quadrajet
There are absolute reasons for Not running a "Standard" OE production car PCV system on performance orientated engines. First to clarify, .... most of the automobile manufacturers found it a viable way to deal with un-burned contaminants (reduce pollution) as well as venting of the crankcase. I feel the most important downfall of the "Standard" PCV system is that as the inevitable piston ring to cylinder wall seal is degraded, ... more volume of contaminants are introduced into the crankcase. At that stage the blow-by mixed with oil mist from the rotating assembly will be introduced into the fresh intake charge. We all know what the risks are when oil is introduced to the back of valves (Deposits) and more importantly the combustion chamber, ...... "Detonation". I am a firm believer that an up to the challenge PCV system is still a very good idea (relieving crankcase pressure), ..... I'll explain how my system is to be orchestrated. The first concern is large oil solids control VIA a proper valley baffle system, which there are a few good options to choose from. My personal choice on this was the TA Performance Valley Tray. The OE Intake/Valley pan works, as well as the AMP pan. It's more than likely personal choice. The second concern is the PCV Valve itself. My choice is the M/E Wagner Performance Dual Flow Adjustable PCV Valve, ... for obvious reasons.... it's Adjustable. The third and "Most Important" component is an oil mist separator installed to ensure a clean "oil and contaminant free" return to the intake charge. My choice here is the Mann-Hummel Pro-Vent 200 Oil Separator. This system not only ensures a clean reentry charge, but also returns the collected oil back to the oil pan so no manual emptying is needed. Some may say "why dump the contaminated oil back to the oil pan?", .... the answer is that once the engine has been operating, the crankcase/sump oil is contaminated to begin with. One side benefit of this system is that the charge that is being drawn back into the combustion chamber has had a chance to cool down, .... (unlike the standard OE PCV system that draws a hot contaminated mix into the intake charge. As always, ..... This is just my view on this topic. Other folks may have their own. Larry
Mark, I took this photo of the three main components of my PCV System today. There are a few things I will still be incorporating into my set-up. I will be drilling the heads of the oil baffle bolts for safety wire. We will be machining a couple vacuum fittings for the Pro-Vent 200. I’m also adding an electric vacuum pump. The pump will be wired to turn on at wide open throttle VIA my (unused) TH400 kick down switch. It will be plumbed in a “Y” configuration with the carburetor and PCV valve. I haven’t decided if I will use 2 check valves (one at the carburetor port and one at the vacuum pump port), or I may use electric switched diverter valves such as affordable common purge solenoids. The reason for the vacuum pump is to evacuate the crankcase at wide open throttle, .... which is when the carburetor vacuum is low. This system may seem overkill but it will keep the crankcase clean and relieve it’s pressure. Because my valve covers have filtered breathers, there is no oil starvation to bearings. Because of the oil separator, there will be no oil entering the vacuum pump to cause damage. Larry
