VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 brass fittings for oil line

This is related to the coolant leak I found when I was trying to start my engine, so I thought I should start a new thread. I had a leak in the brass fitting behind the pushrod cover (36 Master, on the oil line that goes through the block) and it slowly dripped down into the pan. I dropped the pan and fortunately, no corrosion.

I'm curious about what type of fitting was used originally on these. I thought it was supposed to be a double compression fitting. 1/4 inch pipe thread coupler into the block, compression nut for 3/16 inch pipe into the coupler (1/8 inch pipe thread, 3/8 inch -24 actual size). But the coupler with the 1/4 inch pipe threads that I have is not a compression fitting. It is simply a coupler. So there's nothing for the compression nut to seat against. Hence, the coolant was leaking out around the copper pipe. I looked all over for a compression coupler with 1/4 inch male pipe threads and female threads to accept 3/16 inch compression nut (i.e, 3/8-24 threads), but such a beast doesn't seem to exist. So my options are:

1. Use a compression connector into the coupler in the block (3/16" tube size to 1/4" pipe thread, Edellman 112320. This will require drilling out the connector to allow the 3/16 pipe to pass through. Another problem is that the fittings may not fit behind the push rod cover.

2. Make my own custom connector with a 1/4" solid plug. A little tricky since the 3/16 pipe nut has to seat at just the right depth. My tap has too much of a taper to make threads all the way to the stop.

3. Use the 1/4" to 1/8" coupler, and solder pipe to nut. Not my favorite choice, since the block makes such a good heat sink.

Any advice?

This is a little difficult for me to describe but I assume that you have the oil line kit sold by the Filling Stattion. It is the same as what Chevrolet sold for replacement in the later years.
First there should be a bushing that threads into the openings in the block (either side) Then insert the line through the block. Next use the tapered fittings on either side They should thread into the fitttings that you threaded into the block. They will seal in the larger fitting and also compress around the line The nut and sleves in the kit connect the line to the rocker arm line and the fitting on the oil distributor valve fittting on the left side of the block.

The original line used in production had the big fitting soldered onto it for the right side and the line and fitting turned together when installed in the bloac. From there the sleve tapered fitting and large er fitting was used just on the left side.

I suppose this is as clear as mud.

I've got the kit ordered from The Filling Station. I didn't see it at first, since they list it for 1937-1953. I assume that the only difference over the years might be the length of the copper pipe. I'll see if the fittings are different from what I have. I do follow what you wrote. Hopefully, the bushing that the Filling Station sells is a compression fitting. If it's just an open bushing, the tapered fittings have nothing to press against, and even with the fitting (smaller nut) tightened all the way down, it doesn't seal well around the pipe.

If the Filling Station kit doesn't work, I have a homemade solution. I used a tap to thread one of the bushings that goes into the block all the way through. Then I inserted a plug with the right threads into it from the back side, and cemented it in place with some thread locker. Then I drilled a whole through the center for passage of the tube. I used a Dremel tool to shave a taper on the inside of the plug. Now the tapered nut can seat and tighten up.

Actually the correct year application would start at 1936....thats how it is listed in the Chevrolet parts books.

I received the kit from Filling Station today. It's just like the one I had the problem with. The coupler that goes into the block is not a compression fitting. The compression nut tightens all the way down on the coupling without compressing against the copper line. I'm going to try my modified coupler and see how it works.

Then you are doing something wrong. The line should extend through the tapered fitting. When that fitting is tightened into the larger fittting it will squash into the line and will be tight. The first time it may need to be made a little tighter.

The fitting that is in the larger bushing is turned in all the way down. It can't get any tighter. Oil line still slides through loosely. Does the larger bushing have to be completely seated in the block? It goes in a little over halfway before it gets really tight. Maybe it's not allowing enough compression on smaller fitting because it's not in far enough?

I gave up and soldered the pipe to the fitting on the right side only (under pushrod cover). No leaks! My homemade fitting seems to work well on the left side, so fortunately, I won't have to solder both ends. Back to getting 'er started.