VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Oil Delivery Under Valve Cover

Am working on a new-to-me ’54 235. I have not gotten it running yet, but inching that way. In the process, I ran the oil pump with the valve cover off using my cordless screwdriver down thru the distributor hole.

There is a “J” shaped piece of copper tubing up in the rocker arm area. It was completely crimped closed. This did not look right to me, so I un-crimped it about 1/2 way. Oil comes streaming out of it to beat the band! What is this arrangement all about? How should it be configured?

But at the same time, about 1/3 of the rocker arm “weep holes”(?) took forever to weep. Then when they did, they were very anemic compared to the other healthy ones. This may or may not be related to the engine not turning over while I was doing this oil pump test. Might those oil passages be plugged? I tried blowing them out with compressed air, but the air seemed to leak out somewhere & this did not fix it. Is there an easy pipe-cleaner type fix? Or will this work right when I get the whole engine running?

I would begin by removing the rocker assembly and cleaning out the in sides of the shafts. The line can be crimped after the shafts but not before.

I'd like to make a clarification about the "J" shaped copper tubing. It's actually a "candy-cane" shaped. It comes up from the oil pump area, above the center of the rocker arm assembley, then turns back down and abrutly ends. Since being uncrimped and oil flows thru it, the oil just aimlessly squirts down on top of the head. I don't get it.

It is crimped to make more oil flow into the rocker arm shaft to lubricate the rocker arms and valve stems. I would recrimp it back to like it was!

In the low pressure engines it was not crimped from the factory. It was open as a bypass once the rocker arm shafts got full. A lot of people would crimp it to get more pressure to the rockers. If your 235 is a full pressure 235 I imagine it was crimped from the factory but I don't know that for sure. If you re-crimp it I imagine you'll see more oil coming out of the rocker arms. The rockers oil from the bottom up. The oil holes in the rocker shafts are along the bottom which allows oil to access the rocker arms long before the shafts are full of oil. In the low pressure engines it could take some time for the shafts to fill.

Tiny is correct about the time it takes for a low pressure engine to show oil out the weep oils in the top of the rockers arms. On my '37 you can here when the shaft fills up with oil. It gets quieter and quieter as each rocker arm gets full oil flow. At idle on a hot engine that can be well over a minute.

I agree that before you do any changes to the oil supply tube you need to remove and take the rocker arm shaft assemblies apart. If they have been running dry long enough the bottom of the shaft will be scored and the bores in the rocker arm will be worn on the bottom side.

When you remove the rocker arms only loosen each hold down on the rocker arm stand about a turn at a time. There is spring pressure on some of the rocker arms and it will try to push the rocker arm shaft up. I am not sure about these old Chevy's but in some engines you can break the rocker arm shaft if you let it bend too much. Do the reverse when re-installing the shafts. Keeping a uniform load on the shafts prevents problems.

Take lots of pictures and take good notes as you take things apart. At first glance it looks like a simple assembly. After you have had it apart a week or so you will realize when you start to assemble it that everything has a certain position and goes together in a certain order. Without notes and pictures you will have fun trying to figure it out. You want each rocker arm to stay in the same position on the shafts.

It takes time to clean the oil holes in the shaft and rocker arm as well as the grooves in the rocker arm bores. Make sure you do not push the plugs out the end of the shafts when you are cleaning those bores. That gunked up stuff will not come out by just soaking the parts. Most important is the small disc/oil restrictor that goes between the 2 shafts. It needs to be open and in the right position.

A 54 is a high pressure engine.

Hi bloo,

Thanks for catching that nuance.

Regardless of the pressure system I strongly recommend that the rocker arm assembly be removed and taken apart to be cleaned. Even if full pressure goes to the rocker arms it will not clear blockages in all those small orifices.

I agree completely! All the crud that develops up there causes the shafts to get all scored up and worn out unnecessarily.

Gentelmen, thank you for all your input. I have now hand cranked the engine a few times to change the valve positions. Also crimped the tubing back closed, then ran the oil pump with corldess. The weep holes all worked fine now! It doesn't really matter, but that strange tube sticking up going nowhere, then being crimped off entirly is very strange indeed. It must be a vestige of some even further bygone era. On to the next thing to see if this engine runs.

sounds if some one installed a rocker arm oiler kit. It would be an external oil line running from the left side of the block and then around to the pipe plug location on the right side of the head.