The Stovebolt Site Forums The Shop Area Engine Shop oil pump differences

I have two chevy 235 oil pumps apart thought it would be fun to post side-by side pictures:

The one shown on bottom and left in attached photos is a '55-57 model with longer pickup tube matching oil pans of that time.

On top & left is a post-1958 pump; it's internal gear cavities have different profile than the older pump.
Also there's a small lip machined into bottom of cavity, around the perimeter of the driven gear underneath where the teeth mesh... It's definitely not wear, since it's circumference is a little outside the driven gear. Maybe it's just sloppy machining?

Looks like Wendel ran the cutter a smidge too deep. It likely was made on a day other than Tuesday, which was the only day an assembly line worker was likely not to be drunk, hungover, celebrating Hump Day or Friday Eve, or goofing off on a Friday.
Carl

I just checked it out a little closer:

The driven gear, who's pocket appears to be a little deeper, still sits level with the drive gear.

In fact, the surface it sits on is slightly domed. The outer circumference is machined a bit deeper than the middle around the center pin.

It seems like maybe that cutter had a bad tip, but maybe it's intentional?

Just spotted another difference:

The newer pump has a much shorter stroke on the pressure relief plunger
It has the same plunger & spring length, but the travel limiting pin stops the plunger in a more compressed position when there's no oil pressure.