VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 can oil to rockers and valves be improved ?

Has anyone ever tried to increase the oil flow to and around the valves, springs, and rockers themselves by pinching off the copper return tube at that wishbone shaped elbow, even partially ? My retired master mechanic neighbor thinks the area around the valve stems are close to being starved for oil and perhaps it might then be better distributed if that tube's diameter was constricted thereby forcing more oil out the rocker arm holes, hence spraying more oil over all the moving parts while keeping the valves better lubed ?

I only ask since my #6 exhaust valve stuck again yesterday after 10 miles. The underside of the valve cover is dry. Maybe there should be a fine mist coating on it ?
It was the one day I didn't squirt oil into the valve stems before heading out.

So after 15 minutes parked under a shady tree, it started up and ran fine home.

I know the proper fix is to pull the head and re-ream the guides but I'd like to save that for the fall and enjoy the car now. I'm up to 130 miles on the rebuild. Car's a '32 w/ the 194 stock engine. Oil pressure is normal.

Close followers of this site may recall I used the "cordless drill chucked in the stem" trick to free it up the stuck #6 initially. I did it again today….

Thank you !

Is there oil overflowing from the overflow tube. If there is I would try restricting the end of the tube and see if that changes things.
My thoughts are I would do it at the very end so it could be un-done more easily if you wished. This was a common practice years ago.
Some may disagree with me but seeing all other things are clean this could be a last resort.

Thanks Gene.

There IS a pooling of oil around the neck of the overflow tube so I assume the excess oil is draining down into the tube. Is that what you meant by "overflowing down the overflow tube" ? I think the parts manual calls it the Oil Return Tube (Cylinder Head to Block). P/n #835843

Also, don't you mean restrict the end of the (copper) pipe where it ends down in the oil return tube? Sorry, but just want to clarify before I go crimping things.

The oil return tube is the large sheet metal tube directing the oil back to the pan.
I am not 100% sure how the center oil connector looks on a 1932 but yes, crimp the copper tube to the end if possible.

Would be nice if you could try blocking the end of the tube with a screw for a test as it could easily be rmoved

I like the idea of a screw or other removable "plug".

I'll give it a try. The copper pipe simply sticks down into overflow tube from the elbow fitting above it, no connector coupling or sleeve, at least on my beast. I wonder what the purpose was for this pipe overflow. A primitive flow regulator ?

I would worry about the screw coming out. How about a compression fitting with a threaded plug.

Even better.

I see my Photobucket photos fell into that black hole.

Also the 216-135mlater engines also had the overflow. Was used to bing up a lot of oil to keep the line clean and prevent over oiling I would suspect.

The plug could be drilled so it acts as a restriction but still allows some flow.

Charlie,
If I remember correctly my overflow pipe where it is almost into the return pipe has been crimped. I get a lot of oil flow through all my rockers.

On my all original '32, the oil return elbow pipe is not crimped and I get plenty of oil to the rocker arms, valve stems and shaft. And, at idle, hot, my oil pressure gauge reads around 1 or 2 pounds.....just like it should with the original factory oil pump.

Maybe I should have said "slightly flattened" or at least it looked that way when I had the cover off. It's not crimped closed by any means but didn't look perfectly round if I remember correctly.

Is it possible there is a restriction within the rocker tube? Sludge, debris? Maybe the shaft should be removed and flushed out to see.

The one on my 1929 is a little flattened/ crimped. looks like two tubes since it is squished in the middle. my flow was ok when i got the car, will be interesting to see how the flow is with the rocker arms rebuilt and shafts coated and ground. all new bushings, clips, springs, etc...

The entire rocker arm and its components were professionally rebuilt (same shop you used) so there should be no obstruction issue there. Oil weeps out okay from the all shaft holes. Just not crazy pressure.

Meanwhile, I just noticed the copper tube on my junk engine in the barn is crimped too. All this begs the question, what was the original purpose of that copper pipe. To return any excess oil to the bottom end quickly ? I'm sure those early engineers had a reason.

"oil weeps out of the holes OK" indicates working as it should.

why don't you try the already crimped connector and see the difference.

The overflow is to prevent over oiling which can be a problem also. The flowing oil keeps the passages and lines clean. The rocker arms shafts are fed from the low pressure side of the oil distributor and under original conditions it delivers an ample supply of oil.

The increased height of the top of the bend in the tube was to put a little positive pressure on the oil to the valve train so it lubricates to the ends. As the shafts and bushings wear those increased gaps leaked more oil so the ends didn't get oil. Pinching off the tube put more oil to the shafts so they fed all the way to the end. That also caused the oil to drain down in more places increasing leakage from the valve cover, side cover, etc.

Appreciate the explanations !

A friend is having the same problem with a 1934. He soldered the over flow tube end shut and is trying it at this time.

I'd be interested to hear of his results and if any over oiling issues arise.

1933 and later valve rocker shaft and oil connector sleeve p/n 836875 has a smaller opening that seems designed to reduce oil flow to the rear shaft and rockers.

Valve rocker shaft 836815 (1932-33) has oil holes on one side only.

Are there some instructions somewhere in the Chevrolet monthly service news where it says do not close off 836294 oil connector elbow?

The rocker shafts have oiling holes on the bottom only.
The 1933 Engineering Features says the restrictor for the rear shaft is used to preventover oiling caused by the inclination of the engine. In other words reduce the oiling to prevent excessive leakage. It also states that the oiling groves in the rocker arm bushings were made deeper in 1933 to provide better rocker arm oiling.
Page 147 has the complete improved rocker arm oiling story.
I would suspect as the bushings wear the grove becomes more shallow reducing oil flow or if they are replacement bushing ???

Evidently 1932 rocker arm oiling was always a little skimpy from new and improvements were made in 1933 to improve it.

Just got the message to-night. Friend with newly rebuilt '34 and sticking valve no longer has the sticking problem after closing off the over flow tube.
More details to come later.

Encouraging news. Eager to hear any details.