The Stovebolt Site Forums The Shop Area Engine Shop 250 valve cover help

I have a 250 valve cover with three holes, two on top, one on the side. The top rear is PCV valve, top front is oil fill, side is breather pipe to air cleaner. I need the fitting that goes in to the side hole or a plug that fits the side hole. The valve cover has Chevrolet stamped in the top if that helps date it. I have been hunting the web for days and can't find a clear picture of how Chevrolet ran the breather line into the valve cover. I have seen some pictures with a big hose from air filter to valve cover, but they are not clear enough to see how it fits, and why does it need to be so big? The PCV valve uses a 3/8" line, why would the inlet need to be 1" line? I have it set up now with two push in breathers and the PCV going in the side hole. All I am doing is pulling air in the front breather right into the PCV valve, it's not really clearing the block. I want to switch to rear hole for PCV so the system clears the block lkie it's suppose to, plus I have purchased four different NOS inline six PCV valves for testing ( all AC Delco valves ). Chevrolet used four different valves through the years for the 250, so I wanted to try them and see if there is any difference in how the engine acts or what the air/fuel ratio does.

Joe,

Here is a link to a diagram that may be of some help: 250 PCV vacuum diagram

More research needed to try and locate your valve cover side grommet.

Grommet is not to hard to find, the fitting going into it is another story.

Joe,

This may be of some help Google Search for air cleaner to valve cover pipe

One of the parts displayed may be suitable or modified to meet your need as I believe the pipe diameter is the same as what you need.

Also, just to clarify, your "oil fill" hole sounds like it currently has a breather style unit cap???

FWIW, having previously owned a '65 230 with a PCV set-up, that oil fill cap should be closed (solid cap with no breather). I have attached some added pictures that may help demonstrate.

Only difference between the pictures is where your PCV intake line connects, air cleaner bottom of base or side of air cleaner body. Both show a closed (non-vented) oil fill cap.

Let us know if any of this is helpful.

Thanks Dan, my setup does have a breather in the oil fill hole, thats what I'm correcting. I always ran dual breathers, never gave it much thought, but after looking at for a while I seen the mistake, the PCV valve isn't doing its job. I may stick one of the breathers in the side hole and see how it works. The link with the elbows is handy, I looked so long, my search engine just kept giving me the same parts over and over.

Glad the info is of some help Joe.

Just a note that if you are wanting this to be a true "closed" PCV system, use of the "breather" through the side port on valve cover kind of defeats that. I found a small write-up in a Hemmings article which I have clipped as an attachment below to maybe better describe how the "closed" system works.

Others may chime in with added input as may be helpful.

Would be interested to see what you end up with.

Here is what I am working with, all home made pieces. If I can find a fitting to fit the valve cover, then I will add something to the bottom of the air cleaner so it draws clean air into the crankcase. You can just make out the chrome breathers behind both carburetors and the PCV in the side hole of the cover. Both are older pictures, I have rerouted the fuel lines and vacuum advance line since these were taken.

Joe,

Very nice looking set-up you have there.

If you are looking for the grommet set for this (both pcv valve and hose connection), I found that AC Delco # 141-615 is supposed to fit the bill. A quick search online will give you a FLAPS of your choice part number as these are common stock items from what I can tell.

When I get a chance later today, will go out and take a peak in my shed. I may have some bits and pieces to help you out.

More later...

Joe,

Here are a couple items (see attached pics) that can help get your PCV set up to stated result.

The gray item is an aftermarket connector that can be mounted to underside of your air filter lower pan to use for connecting hose from valve cover side port. The other is a multi-use port plug or grommet which is stepped so can be used as plug, PCV grommet, or side port pipe grommet. This assumes you will relocate the existing PCV valve and grommet from side port to rear port of valve cover.

They are leftovers from another long ago project which I don’t need. Yours if you want them.

You will still need the elbow pipe and section of hose to connect the filter inlet adapter.

From your noted location, I am near and could meet up at a time location of your convenience. Send me a PM and we can discuss further if you’re interested.

Looking forward to hearing from you.

Edit: I did hear from Joe. We plan to connect in the future to get this thing figured out. More to come later 👍