VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 1933 Oil Pump

I recently purchased a NOS oil pump for my 33 master, part#604173. The driveshaft in it has a female end, the one I am replacing is also part#604173. The driveshaft in it has a male end. Since my distributor shaft has a female end should I attempt to switch oil pump shafts in order to use the new pump?

hoppy

I can't find the 604173 number in any of my books. Is it a part number or a casting number? I would guess its the casting number used for the replacement gear type oil pumps for 1932-36 engines.
The 1929-35 oil pump has a male end connection and the distributor is female. The 1936 changed to the female oil pump .
From the 604173 number it sounds as if both pumps are the later gear type pumps Chevrolet sold for replacement for the vane pump. The gear type pump will have an oval screen, the original vane type pumps used up through 1936 have round screens.
It appears that you have a replacemt type 1936 pump...and I believe that you will find it also has a larger opening for the oil feed line. The 1936 pump was all by its self due to the change in connections. The main difference is the femal shaft.
If your old pump is of the gear type I would just continue to use it as it has been replaced some time in the '40's and should still be in good condition.
Does any of this add up?

I should add further that the replacement oil pumps were sold as a "kit" and came with the screen,tin screen cover,lines and fittings necessary to install it in a particular year engine. Due to differences is engines there was one "kit" for 1929, one for 1930-34 EXCEPT 1933-34 Masters, one for 1933-34 Masters, one for 1935 and one for 1936. If you bought just the bare pump with that casting number the addtional parts were lost or thrown away over the years, which is common if the box fell apart. I would guess that at least the 1933,34 Master pumps and the 1935, 36 pumps used the same housing if not all. It was basicly a 1937-39 design pump adapted to fit the earlier engines.

after giving this some thought I remembered that I had some of the new replacement gear type oil pumps on hand.....and they all have the 604173 number on the pump and 604168 on the pump cover. That being said I wuold suggest that you keep the pump that was on the engine. It can't have that many miles on it and most gear type pumps lasted longer than the engines. The 1936 pump will make a good paper weight if you don't have the hardware to go with it. :)

Another precaution - Make sure the valve in the oil pump cover is free to move. This can be checked with out removing the cover.Its spring loaded and is what controlls the maximum oil pressure that the pump can produce (with cold oil)...its about 80 pounds with this pump. If stuck "open" it can cause the pmup to produce low pressure.

Gene--Thanks for taking the time to answer my question. I did clean up the old pump made a female rod to attach to a drill (variable speed) and tested it at low speed in a large pan of drain oil and it pumped oil like crazy. Both of the 604173 pumps are gear type with oval screens. I took them both apart and think I could just exchange the shafts since both pumps are the same in every detail, but I think I will take your advise and use the one that came out of the engine and save or resell the NOS pump.

hoppy

Note that if the pump cover is removed the correct GM gasket must be used for replacement. It is a specified thickness. If too thin the pump gears will be too tight, if too thick the oil pressure will be low. Chevrolet never sold the internal parts as they were matched together at the factory.

Gene--The gaskets were still ok.