NOT GMT400 RELATED. '09 5.3L oil pressure issue

[0xDEADBEEF]

The Gen III has a gerotor pump with a spring. I really don't understand how it works, but there's a spring and a sort of valve. Maybe that's the bypass valve?

Yep that's the bypass. You can put a stiffer spring in it to make more peak pressure.

It's kind of like the Wankel of pumps. The rotor blocks and unblocks the inlet and outlet ports as it turns. Each lobe is a little chamber that fills up with oil as it passes the inlet, then as it rotates it gets pushed over to the other side and squished out the outlet.

 

[Erik the Awful]

It's kind of like the Wankel of pumps.

Similarish, but nope. The Wankel engine was originally designed as a pump, and then Wankel realized he could make an engine out of it. It has an epitrochoid-shaped housing and a reuleaux triangle-shaped rotor that has a complex rotating motion. https://en.wikipedia.org/wiki/Wankel_engine

A gerotor pump is simply two gears that spin, pushing the fluid. https://en.wikipedia.org/wiki/Gerotor

 

[0xDEADBEEF]

Similarish, but nope. The Wankel engine was originally designed as a pump, and then Wankel realized he could make an engine out of it. It has an epitrochoid-shaped housing and a reuleaux triangle-shaped rotor that has a complex rotating motion. https://en.wikipedia.org/wiki/Wankel_engine

A gerotor pump is simply two gears that spin, pushing the fluid. https://en.wikipedia.org/wiki/Gerotor

You can spin 2 gears all kinds of different ways that don't make an oil pump. What happens at the ports makes it a pump, and to me it kind of reminds me of Wankel.