Oil pump

[Tevel Jean-Jacques]

Morning all,

I'm (finally) working on replacing my oil pump. I removed the pan, and the pump is now off the engine.

I now have a question that some of you might feel strange. On the iron stamped cover, I have a grove machined in the inside of the cover and a hole is drilled in it allowing the oil to get out of the pump (directly to the pan). I don't know why it is there, and to be honest, even don't know if it is supposed to be there. I have worked out and rebuilt many other oil pump (but that's the first one for a Kaiser), but that's the first time I see this.

As mentioned earlier, my oil pressure is not good, but controlling the two pumps gears, I feel they are not that worn. I have a new set, so I will replace them anyway, but the question is now could the hole in the cover be the cause of lack of pressure??? <should it be there, and if not do I have to fill it?

Many thanks in advance for your answers and advises.
Have a great day.
JJ.

[joefrazer]

The oil pump body is cast iron and the bottom cover is stamped steel. The two metals heat at different rates and this can cause many problems. One is as you see, a hole is worn in the bottom cover.

What’s happening is that the pump gear is sliding down and wearing a hole in the bottom cover. The entire oil pump assembly should be replaced. They can be rebuilt but you would be better off replacing the pump.

[Tevel Jean-Jacques]

Hi Joe

Thanks for your input.
In fact here, this is not one of the gears that caused the hole. This was done by somebody machining the cover, and I just don't understand why. (I tried to attache some picture to this answer, but with no success).

When the cover is on and looking through the small hole (± 4 mm diam) I can see the gears rotating. Could confirm that there is no hole on the cover?

Thanks again.
JJ.

[rrdcorvair]

Hi,  I checked three used oil pumps I have saved to possibly rebuild and all three have a small hole drilled next to the cast part for the oil pump float to attach to.  All three are the same size and location, must be factory and meant to be there.  Maybe it is a by-pass hole. If you want I have several new oil pumps packed up on shelves and I could open one and check one, too.