The Stovebolt Site Forums The Shop Area Engine Shop Valve Cover mystery

59 Apache 32 with a 235, what was the "original" valve cover set up? I currently have a Chevrolet stamped valve cover with a center oil fill. Standard cap, not a breather type and what appears to be a non factory hole in the front LH side of the valve cover with a grommet and a PCV . The engine does not have the breather tube assembly on it that would be in front of the distributor and that breather hole has what looks like a factory plug in it. Thinking someone previously made some changes and I would like to have it returned to its original set up. Any help is appreciated!

Do you have a 1959 Truck Shop Manual?

In 1960, the PVC hose on a 261 ran from the carburetor air cleaner to the left rear of the valve cover.

The 1959 valve cover might have had the oil filler in the middle of the valve cover.
A non-vented oil filler cap would have been used with a PCV system.

A member has designed an after-market PVC set-up for 235/261 engines. Maybe he will post info, or someone will post a link to his web site (that has detailed instructions)?

My '59 261 has the non-vented cap in the center of the valve cover and the small plate with nipple & grommet is at the driver side rear of the valve cover for a hose to go to the air cleaner. The PCV pipe ran over the top of valve cover from the breather tube to the intake manifold. Don't know if 235 was different.

http://pugetsoundvintagechevrolet.org/Programs/6%20cylinder%20engines%20with%20photos.pdf


Scroll down to the bottom of page 4.

(thanks to Pre '68 Dave)

Page 4 shows what I have! Guessing somebody added the PCV as the hole they made is not very cleanly done. Now the question is, am I suppose to have the road breather in front of the distributor then?

Great pictures! I see in one of them where your cylinder head has a 1/8" tube coming off the passenger side of it in the center. You have it circled with red, I have that too, any idea what its for? Guessing its a oil supply to the rockers? mine comes off of the drivers side down low where the I/P oil pressure gauge feeds to. Can't find that in the assembly manual. Just curious, thanks

Wrencher88,

If you're talking about my engine pic's, my oil pressure gauge WAS hooked up to that fitting, but that is a bad place to hook it up because there isn't much pressure there.... that hole is now plugged.

I don't know what that hole is for. Maybe you have a secondary/parallel oil circuit to the rockers? I don't think that was stock... interesting.

Looked at it a bit more tonight after I torqued the head and installed the rocker arm assembly. The oil return line on the rocker assembly is crimped at the top of the arch and a hole added on the bottom side of the line. Gonna take a guess that the return line was crimped and the hole drilled to add more oil to the rocker area. Thought I read somewhere that the 235 had some issues with not enough oil to the rockers but I could be wrong.

A 58-59 235 has the vented oil fill cap in the middle of the cover.

Wrencher88, it was fairly common to add a tee to the oil gauge fitting and run a copper line to the 1/8" NPT fitting at the top of the head on the passenger side between #3 and #4 cylinders. That hole normally has a plug in it, but the plug can be pulled to have an auxiliary oil line to the rockers.

If you look on eBay, you can probably find a kit for the auxiliary oil line.

Sometimes the line to head that runs inside the block (newer engines) or through the oil feed tube inside the pushrod cover (older engines) gets blocked. The auxiliary oil line is a way to get oil to the rockers if the primary line is blocked.

Crimping the oil feed tube was commonly done to force more oil through the rockers instead of allowing some oil to bypass the rockers to the return loop. Crimping it forced all oil through the rockers. Crimping the line was VERY common. Chevy changed to a crimped design from the factory in 1959. Drilling a hole into crimped fitting sort of defeats the purpose of crimping it, so I'm not sure why someone would have done that.

Matt

The 1958 and earlier tubes that loop over and back down to the head had a hole in the underside of the tube at its highest point of the loop. It is possible that the tube is a early style that has been crimped after the hole.

Wrencher88 -

I posted a similar question on Stovebolt in 2011 about the valve cover on my '54. "CrankyOldDude" responded with a good answer. Since you are in California, perhaps his answer applies to your truck, too.

"... AC (AC spark plug of General Motors Corporation) California State Approved crankcase ventilation system. California required most 1950 and later cars and trucks to be retrofitted with a PVC system when a used vehicle was sold. The program originally started from January 1, 1964 and ran through January 1, 1966."

Full text of CrankyOldDude's answer

My original question and photos

- Lonnie

Very interesting, Lonnie

Thanks

That is some great information Maybellene! The drilled hole is after the crimp in the return line, not sure what they were doing with that either. I already have the aux oil line to the the head. Wasn't sure if I should leave it or not, but now that I know why its there I will surely leave it.
My plan is now to repair the PCV hole in the side of the valve cover and mount it in the road draft plug and install a breather oil fill cap. They had the PCV mounted in the front drivers side of the valve cover but no way for the engine to pull fresh air as the oil filler cap is a non breather type.
Thanks for the information it is greatly appreciated!

I ran a shop in California in the middle to late 1970's, and we retrofitted several vehicles to closed-loop PCV systems. It was a requirement enforced by the local DMV that no open-crankcase systems were allowed to be registered when ownership changed. The vehicle also had to pass a visual inspection and an exhaust emissions test, performed by a state-licensed shop. Fresh air was drawn from the "clean" side of the air cleaner by installing a vent tube from the air cleaner to the valve cover, and a PCV valve was installed in place of the road draft tube. Any vents, such as valve cover slots or vented filler caps had to be disabled.
Jerry

This is all great information! I'm guessing that's why it was installed. I'm looking at mounting the PCV in the road draft plug and making a line to the intake connection. Because I have the original oil bath air cleaner I will need to change the oil fill cap to a breather type also I believe? The truck had the PCV with a closed fill cap when I bought it, have had no issues but I'm not sure you can supply fresh air from an oil bath type air cleaner? Thoughts?

The vented fill cap will do a good job of supplying air to the crankcase for the PCV to draw into the intake manifold. It will provide a positive flow of air through the valve cover and down into the crankcase, taking blow-by and combustion gases with it.

You will need to have a riser tube of some type at the road draft tube hole to prevent the PCV from drawing splashed oil into the manifold and causing the engine to consume a lot of oil. Most people use a regular road draft tube base, and adapt a rubber grommet to it for the PCV valve to plug into instead of the tube that hangs down into the air stream.
Jerry

Wrencher88, you can vent your engine with filtered air using an oil bath air cleaner.

I have an oil bath air cleaner from a '55 4400 that had been converted as Jerry describes. It has the fitting for attaching a rubber tube to the valve cover. Here are some pix--

http://s844.photobucket.com/user/ma...2957_zpstifwvvec.jpg.html?sort=3&o=1

I converted to a PCV system on one of my engines. I use a vented oil fill cap. My plan was to use this air filter to vent the engine with filtered air, but I decided to keep the stock vented oil cap instead. I removed the guts to install a modern, dry filter but never got that far.

If you (or anyone else) wants this air filter for your project, you can have it. Just send me a PM. Forgive me for inserting this information here instead of under Freebies in the Swap Meet, but I thought it made more sense here to potentially help a fellow 'bolter. Please send a PM if interested so that we don't clutter this topic.

Matt

I have a '58 261 that I removed from a '58 Viking C60 that was completely un-molested before I got it. I think it still has the original spark plug wires on it. IT has a chevrolet script valve cover on it with a standard oil fill cap but it's located on the front of the valve cover - not in the middle. This engine also had a factor PCV system on it with no draft tube.

The funny part to all the California retro fit PCV system is now, anything prior to 74 has no "Smog" inspection at all! The DMV would never even know if I put the road draft tube and vented oil filler back on it! I guess I could be a rebel if I wanted too but think I will stay with keeping it running clean! This has been one of the best posts I've done in my short time, very cool to learn all this and to see I'm not the only one experiencing it!