pcv question

[75_chevy]

I have a breather on my passenger valve cover and a pcv on my driver side. I am having a problem with my engine burning a lot of oil and I can see the carb is sucking oil up through the pcv. is that normal for the engine to be sucking up the oil? I've thought about moving the pcv to the passenger would that help reduce the amount of oil getting sucked up? if I do move the pcv to passenger side where should I connect my charcoal canister vacuum line? I have them connected through a T. thanks for the help.


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[rich weyand]

Replace the PCV valve.  It is supposed to open under vacuum (such as at idle) to ventilate the crankcase, and then close when you get on it so it doesn't suck oil.  It sounds like it is stuck open.

You could clean it out, I suppose.  A good one will rattle when shaken.  But new they're like four bucks.

[75_chevy]

thanks rich, i got the pcv for Christmas and it's a very heavy duty piece, it rattled when I shook it so I think it should still be functioning ok. see how I have it T'd in with the charcoal canister? maybe it pcv is not fully shutting under high vacuum pulls because the charcoal canister is letting air through the carb as well.. if I connect the pcv straight to the carb I think the valve can do it's job right, but then where do I hook up the charcoal canister line? thanks


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[bd]

Curious - the "PCV valve" in your image looks like a simple closed breather element. 

Both the PCV valve and breather should push into grommeted, baffled holes in the valve covers.  Baffles prevent direct oil splash into the valve/breather openings.  If the baffles are absent, liquid oil can be drawn into the intake and burned, causing abnormal oil consumption.  Most valve covers have either integral baffles, or "tower" bosses by which you can install optional baffles (usually using tap-in rivets).  Pull the PCV valve and breather out of the valve covers and make sure that the baffles are installed.

The vacuum plumbing in your image looks okay as long as the canister hose routes to the appropriate vacuum nipple.

[rich weyand]

This is a normal PCV valve:



What that looks like is a breather that is meant to hook up to the air cleaner, as on my truck here:



To review:

There should be a PCV valve hooked up to the carb vacuum as you show, but I don't think that's a PCV valve.

There should be a breather on the other side, which can be standalone, or may hook up to the air cleaner.

[75_chevy]

ok I got it now I think I'll have to drill a hole in my air cleaner housing then. what sort of fitting should I install onto the housing to hook the breather up to? so I'll move this breather over to the passenger side and I'll get a PVC like that from monument car parts or something. thank you guys


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[75_chevy]

also there are baffled grommets in there for sure


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[rich weyand]

Don't drill the air cleaner.  Get a standalone breather with an air filter built in like this.  Replace it every couple years to get one with a clean air filter.  This one may fit; check the size of the hole in your valve cover.
http://shop.advanceautoparts.com/p/mr.-gasket-breather-oil-filler-cap-2061/6091059-P?searchTerm=breather+cap

For the PCV valve, you will also need the grommet.  It goes into a smaller hole, so you need the grommet with the same OD as the one you have, but the smaller ID that fits the PCV valve.

[timthescarrd]

There are PCV valves that look like breathers.  if it rattles, it's probably a PCV, though it could be a broken breather, hard to tell.  Most Open Element air filter housings like you have, have a knock-out plug on the bottom plate and come with a hose fitting for running a tube to the breather. 

A baffle and a grommet are two different things.  baffles are metal pieces inside the valve cover to prevent oil splashing like this:



Grommets are the rubber push-in circles designed to seal around the vavle/breater like this:

[75_chevy]

alright cool thank you guys and yea my housing has the spot where u can punch a hole out for a pcv so I'll check the box and see if it came with the hose. and Tim it is actually a baffled grommet it has extra rubber and has two walls and it's supposed to keep the oil out


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[75_chevy]

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[muldoon]

I saw this thread and it reminded me of a question I have had for a while. 

My PCV seems fine, it rattles and has a good connection, but the grommet/boot it sits in seems loose around the top of the cover.  I sometimes see a smidgeon of oil around it but never alot.  How tight of a fit should that grommet have?  Should it seal tight?  What problems might you see if it was not?