Call me old school 
PCV system vs. Breather......Fight!
PCV system vs. Breather......Fight! Ok, Ive used the search function, done my reading, and have been running a catch can on my LS6 for the past year, and while it has cut down on the oil consumption, it certainly hasnt eliminated it.
My question is, besides the emissions requirements, is there any REAL benefit or need for the PCV system? I know its supposed to use the vacuum created by the fresh air entering the intake to evacuate the pressure and gases in the crank case. I know there are plenty of guys running around with breathers on both the valve cover and the crank case vent on the valley cover, has anyone actually had a problem with this set up?
So far, anyone Ive talked to who has ditched the PCV system has had no ill effects with the benefit of zero oil entering the combustion chamber.
Additionally, any LS series motor ive ever seen dropped into and older car hasnt run any sort of PCV system, whether it be carbed or fuel injected. This leave me to believe that the primary reason for the system is emissions compliance with a small secondary benefit being some increased scavenging of crank case gases.
Im open to any and all input, and not in love with any one theory. If there is some valid, proven performance or longevity reason for the system, then Im all for keeping it. But if its simply for emissions compliance, Id very much like to ditch the entire thing. I assure you the car doesnt get driven enough to adversely effect the environment.
My question is, besides the emissions requirements, is there any REAL benefit or need for the PCV system? I know its supposed to use the vacuum created by the fresh air entering the intake to evacuate the pressure and gases in the crank case. I know there are plenty of guys running around with breathers on both the valve cover and the crank case vent on the valley cover, has anyone actually had a problem with this set up?
So far, anyone Ive talked to who has ditched the PCV system has had no ill effects with the benefit of zero oil entering the combustion chamber.
Additionally, any LS series motor ive ever seen dropped into and older car hasnt run any sort of PCV system, whether it be carbed or fuel injected. This leave me to believe that the primary reason for the system is emissions compliance with a small secondary benefit being some increased scavenging of crank case gases.
Im open to any and all input, and not in love with any one theory. If there is some valid, proven performance or longevity reason for the system, then Im all for keeping it. But if its simply for emissions compliance, Id very much like to ditch the entire thing. I assure you the car doesnt get driven enough to adversely effect the environment.
As a Lightning owner, I know a good bit about pcv systems vs breathers.... I went breathers for about a year and had oil all over the block because of it. NASTY...... Went with my 2nd built motor and ran the system back but with a separator (like a catch can) and have not looked back since. Also.... I drove about 6 months on my 2nd build before I went with a ported blower. Pulled the stock blower and my intercooler was clean as a whistle compared to the non separator intercooler nasty oil brown. Oil consumption through the pcv is multiplied because of the blower and the design by FORD.
thanks for the info. Thats interesting because when I installed my can a year ago, I pulled my FAST intake, disassembled it, cleaned it, and rebuild it with all new seals. When I pulled it for my head upgrade, it was still completely coated with a glaze of oil. Not nearly as bad as it was before the can, but still more than I anticipated. Im still contemplating the breather just to see how it works.
I deleted the factory pcv system and run "MIGHTYMOUSE's" vented catch can. It's a great setup with no negative side effects. Just delete the factory pcv system and make sure your catch can is routed properly, you won't regret it. I don't have an odor either.
Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
I'm running a hybrid version. Rear ports on valve covers are deleted, LS6 vented valley cover, and a GM vented oil cap (part for 4 and 6 cylinder engines up north). Works like a charm.
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so just to clarify, you're running a vented oil cap on the valve covers and vented valley cover with the port on the intake capped off?
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TECH Resident
Joined: May 2011
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From: Leander TX
catch can here
Fresh Air port goes from passenger side to the T-Body, back port on the passenger side is plugged and a hose runs from the driver cover to a PCV valve, into a catch can and then into the intake... catches about 100ml of oil per oil change... glad that isnt going into my engine...
Fresh Air port goes from passenger side to the T-Body, back port on the passenger side is plugged and a hose runs from the driver cover to a PCV valve, into a catch can and then into the intake... catches about 100ml of oil per oil change... glad that isnt going into my engine...
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Rears on the valve covers are blocked off. New version LS6 (integrated catch system built in) valley goes to intake neck. One oil fill cap that's vented by GM for cars in sub-zero temps. Cap was $15, LS6 valley was $70, and new LS6 pull off valve covers were about $40.
PCV systems are unnecessary as long as you change the oil every 3,000 miles. I ran my 427ci without it for TWO full years, daily driver...100% NO PCV system. Capped off intake vacuum port and put a fuel filter as a vent on the rear drivers side valve cover and one on the LS6 valley cover port.
Oil was as clean as its always been at my oil changes and zero water ever in the oil......
Worked perfect. After two years I put a valve in line with the vacuum line and PCV line so I can adjust the strength of the vacuum to what I want. It worked perfect for about 5 years after that.
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Oil was as clean as its always been at my oil changes and zero water ever in the oil......
Worked perfect. After two years I put a valve in line with the vacuum line and PCV line so I can adjust the strength of the vacuum to what I want. It worked perfect for about 5 years after that.
.
I don't like breathers because of the oil mist that gets on everything in the engine bay. Having a way to circulate air through the crankcase is better for the engine. i.e. fresh air in one side, nasty air pulled out via intake vacuum. But when you get into forced induction then things change a bit since you don't want oil in your intercooler, turbo or blower.
Last edited by mean_greenZ; Nov 1, 2012 at 11:12 AM.
