Thanks for the post!

BTW, what is the model# of the pump? It should be a three letter model, i.e. "321", "331", etc..

This appears to be a 321TV Pump.

That pump requires enough RPM to keep the unloader weights retracted.

Since the pump is slowing down under load, the RPM is dropping below the minimum and it is unloading.

90% of the time, Low RPM is caused by OLD hard belts. Change the Belt, Tension should be about one half inch deflection or give at a point halfway between pulleys when pressed with your thumb. Do not over tighten belt, it will break the crankshaft or burn up a bearing.

Compressors do NOT squeal when the belts slip. It sounds like the motor is slowing down. But what is really happening is the belt is slipping.

I am not sure you have the right motor pulling this pump. The Pump should be turning about 500 RPM.

All depends on the Motor HP and the Motor RPM. If this was a 230 V motor converted to 120, you may have lost some pulling power. If it is the wrong motor not matching the correct motor pulley you may be overloading the motor.

That cloth around the motor looks like a fire hazard and it may over heat the motor, by the way.

You're right, there are special valve tools for removing the valve covers on Kellogg pumps, you can view them here:
www.mastertoolrepair.com/kellogg-valve-t...it-r3024-p-5482.html

Obviously they're not cheap, but a repair shop with have them handy. You may be able to use something around the garage to jerry-rig it so you can remove the valve covers.

Typically the problem you're having is related to Valves, so it was a good idea to order a valve kit. If the valves are sticking/rusted, you will get too much positive pressure built up in the craenkcase, which can cause an oil/air leak from the crankcase breather or somewhere else.

I'll see if I can get some more info for you and reply.

- MTR

Okay that's what I thought, I edited my first reply with more info, please take a look!

- MTR

Just to be sure, measure these specs for me:

1. Motor Pulley Diameter (outside diameter)

2. Pump Flywheel Diameter (outside)

These specs will tell me exactly if the motor is working too hard or not.

Thanks!