The Stovebolt Site Forums The Shop Area The HiPo Shop PCV sucking engine oil

My 47 has been burning quite a bit of oil, even to the point of spewing oil on start up. I was thinking it was engine wear, but now I think it's the PCV valve sucking oil. I like the old school look and want to keep it if possible.
When I put the valve covers on I put a hole in one and welded a baffle in that was removed from a stock '70s cover. Then added a grommet and put the PCV valve in the stock location. The hose goes directly into the manifold.
The motor is a basically stock 350 4bbl.

I'm thinking several thing but could use some advice/ideas. The baffle might need to have better weld coverage to keep oil from coming in from the side/top of the baffle.

Are there different PCV valves that I could try? Should I add a breather to the other side? Is running the hose directly into the manifold to much suction?

It's pretty cold here in central Michigan so I likely won't be addressing the issue for a couple months, but want to have a plan.

So, where does your engine ventilation come in from? Doesn't look like anywhere. So the vacuum of the intake is going to draw that from the engine/oil area through the PCV.

Early SBC breathing was in the ventilated oil filler cap and out the road draft tube.

Where do you put oil in at? Maybe you need to put in an oil filler (ventilated) cap on the opposite valve cover while still maintaining your old school look?

Mark you need a fresh air breather at some point, preferably at a level above your PCV. My 327 has an oil filler tube at the front of the manifold, I added a breather cap there.

Check out Lugnutz post in the Engine Shop on this subject, many folks added ideas on how to route the PCV system to add filtered air for the crankcase.

Either put a grommet into the other valve cover and run a fresh air tube to the "clean" side of that Cadillac air cleaner, or put a ventilated cap on the oil filler (wherever that happens to be). Crankcase ventilation has to have an air inlet somewhere to avoid creating a big vacuum in the crankcase and sucking up oil.
Jerry

Best way to do it in my opinion is have the PVC valve on the top of one valve cover, and a breather cap on the opposite valve cover. This setup will ensure that you will be removing the nasty watery steam contaminates which likes to collect on the undersides of the valve covers.
Instead of the vented oil cap, you could plumb a hose from the top of the valve cover to a fitting on the air cleaner, providing for a cleaner source of fresh air than what a vented oil cap delivers.

The vented oil filler tube cap I used has filter material much the same as an oil bath air cleaner would use. The valve covers I used have holes and baffles for the PCV, I only used one side for the valve to fitted in as my manifold had the filler tube and I wanted to stay with the look of the early V8. I routed the plug wires over the PCV on that side, you really need to look to see the valve and hose.

So where do you add your oil from?

I've added oil through the hole where the PCV valve is. I like the idea of the breather tube in front of the motor. I had an old 327 that had that. This 350 manifold isn't set up for it though.

So my current plan is to add this breather to the other valve cover. Seems like the easiest. Not sure why I didn't realize I'd need some fresh air inlet to balance things out. Thanks for the input fellas. I appreciate the advice.

You could add another baffle at the rear of the opposite valve cover and route a clean air hose/tube to the base of your air cleaner as HRL and 52carl suggested. The hose would be easy to hide at the rear of the engine and allow you to keep the old style valve cover look.

If you look at the picture of my 327 you can hardly see the PCV grommet and hose on the drivers side. Once it's in the chassis it will be even harder to see.

I'm liking that idea more and more.

I'm doing dumb things for engine breathing. But who doesn't like cleaning up oil mist daily?

But it's so COOL😎

Planning on doing it like the photo. Basic breather on the passenger side of the truck. Do I need a baffle under the breather? I kinda didn't think I would because air should be sucking in there.

Probably not. Be sure your grommet is positioned between the cylinders so there won't be any contact with the rocker arms as they move. Those shorty valve covers are a pretty close fit to the rockers. On the mid-1950's Oldsmobile engines, we had to put spacers under the valve covers or dimple the covers over each rocker arm when running a high lift Isky cam to keep the rockers from hitting the covers!
Jerry

Thanks Jerry, Yep I've got a small block on a stand in my office. Looks like right in line with the screws is a good spot.

Just Mark I suppose you know that powerful vacuum can suck the gaskets out or colapse the oil pan and valve covers ?? You might cheat like GMC did and screw a PCV valve in an intake port runner into the valley below the carb hidden,sneaky !!!

Just Mark reply went in the cloud