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not running a pcv

B

blue65coupe

Well-Known Member
I bought oil filler/breather caps to match my new valve covers. Well, they came in and are identical. There is no pcv outlet on either one but both caps are baffled/breathable. Anybody running this style of cap on both sides with no pcv hookup to the carb? Any problems? I'm planning on getting a pcv cap for proper ventilation but figured I'd throw this out and see if there are differing opinions.
 
I'm going to be running an inline PCV between the passenger oil cap and the carb. On the driver's side I'm running a hose from the driver's cap and air cleaner.
 
Didn't one of them come with a hose nipple? When I bought my matching breathers one had a PCV nipple and the other did not.
 
"buening" said:
Didn't one of them come with a hose nipple?
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Nope. I'll probably just run the valve into the grommet with no cap. Eh, at least I'll have an extra cap to go along with all my extra "in working order" parts.
 
I would recommend one Duane. Otherwise, I would think, overtime you will start getting some oil blow by on your valve covers.
 
The PCV valve is most an admissions thing. It returns the gases back to the combustion chamber. With out it, those gases just leak through the breather into the atmosphere. Al Gore says run one! :lol
 
"lethal289" said:
The PCV valve is most an admissions thing.
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What is the PCV valve getting admitted to? Or is the PCV valve the secret decoder ring that gets to admitted into Al Gore's secret society? :craz :craz

It's mostly there for the emissions.
 
I don't have a PCV valve, but I do have both breathers plumbed into the header on their respective sides. The exhaust creates just a little suction that pulls the gases out of the valve covers and burns it up in the pipes. No side effects (so far), no oil on the covers and no color change at the exhaust tips.

Apparently this is a drag racing trick told to me by a...........drag racer. I used to get oil on the valve covers before I re-routed them to the headers.
 
"buening" said:
I hear that running without one will eventually require a carb rebuild :scar :lol
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LMAO, good one.
Welllllllllllllllll, considering I was running it before and had to, or didn't, but did, but didn't need to....whatever. I understand the burning of the vapor but was also wondering about the ventilation considering both caps are filtered/baffled. I checked today and the pcv fits snug into the grommet so I'll just pop it in there. I would really like the look of both caps being on but can't get a definitive "it's ok".


And Jake, do you expect us to believe that was for my enjoyment? Alrighty then.
 
The header evac that SilverBlue is running is a great idea. Way better than a pcv. It can also help cut down on pesky little drips like around the rear main seal, etc. I plan on using that system with my new engine.
 
"Fast68back" said:
You don't drive it....
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But i got hours of run time now and a couple oil changes. So far i haven't any problems.
:pbj. Duane, i know you love that stuff!

When building my motor, i planned on running one. The stock 289 2 valve, had the PCV to the intake. I thought i would duplicate that, but the machine shop that did the boring of my block told me he wouldn't run one. I asked a couple different summit techs and gear heads i know, to see about putting one in place of a breather, and i was told without prolonged high reving, like track driving or racing, i shouldn't have any issue. Some research suggests that the PCV's sole responsiblility in a carburated engine is to reduce emissions of gases by putting them back through the combustion chamber.

My understanding, is If the breather filter element gets clogged, and oil comes out onto the valve cover, the breather needs cleaned or changed. At or about the same point, the PCV valve will need replaced. Im sure in some states, the valve is absolutely necessary. In others, not so much. IMO, Marks idea is the best, but not needed on a 99% street driven cruiser.
 
The stock PCV system actually causes a flow of fresh air thru the engine, normally from the filtered cap on the drivers side to the pcv valve on the drivers side. This flow is also controlled by the specific spring tension in the pcv valve Valve must be correct for the engine application. The drivers side is either a filtered cap or one with a hose that runs to the inside of the regular air filter t5o get clean air from. The pcv valve also works off of engine vacuum, with the valve actually opening and closing based on engine vac. against the spring in the valve. More vac. from the carb thru the large pcv valve hose, and the valve opens and draws air thru.

Running with two filtered caps will not provide a "flow" thru the engine as originally designed. Air will move due to heat build up internally displacing the air or from air flow past the caps from the engine fan or other air flow under the hood.

The tubes run into the headers is a good system but it should have only one side run into the headers and a filtered intake from the other side. This would be the same as the setup with the pcv valve, just replacing the valve and hose to the carb with the header hook up.

This air flow thru the internal workings of the engine will provide some cooling, a relief of internal pressure, and a source for the leftover "crap" in those gases to be burnt off. With older engines with some blow by, this will also prevent excess oil from collectinf in one of the caps and dripping onto the valve covers.

This is my findings which may vary from yours........I would and do run a pcv valve and one filtered cap.
 
"gwstang" said:
Craig, it is rumored that Midlife has a pvc running out of his...well you know...lol.
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Is that to reduce the amount of greenhouse gases he emits??? :craz
 
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