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Old Westinghouse 2YC Compressor Questions


This is more of a curiosity post then help needed. LONG POST WARNING If you dont want the story, skip to the second paragraph.
In the mid 80s my dad bought an used Westinghouse 2YC pump alone with no known history. He also acquired a used Baldor 5HP 3ph continuous duty motor and made his own static converter to run it. He got it all running with a 50gal tank but never really used it. He had plans to paint cars, do body work etc but he got busy with family and kids (thanks dad!) and it sat unused for 10+ years. Its now back to running condition and i have been tinkering with it and using for garage shop use. Never put much thought into how much air it pumped until recently because it was mostly used for pumping up tires, running an impact wrench here and there etc.

I have recently starting using it for running air die grinders, sanders, cut off wheels etc and noticed it only maintains about 80-85psi while running most grinders hard. I tried to find specs on what this unit should make, but came up with nothing (not surprised).
I did a 0-120 test which took 5:13 which with my math comes out to 10.4CFM
I then did a 90-120 test and came up with 12CFM.
The 10CFM results seemed a little disappointing, maybe thats about all its built to put out? not sure. This is all with the pump spinning about 750rpm, should i spin it faster?

Put a pressure gauge in the intercooler, came up with about 50-55 psi at 120psi tank pressure. Start with the tank at 0, the first stage seems to climb in pressure equal to tank pressure till about 40, then tank pressure seems climb faster but first stage pressure doesnt stop climbing till about 90psi tank pressure. i know on quincy compressors they say first stage pressure shouldnt exceed about 40psi, would that number be true for any 2 stage compressor?

Anyone have any information on how to test a compressor for proper performance? i wouldnt mind throwing some rings and valves in it if i knew it would increase performance but i dont want to be wasting money and time if i wont gain much. If just valves would make a big difference that is a much cheaper step, but how do i know?

Any info or anything of that nature would be fantastic, i love this old thing and plan to keep it around for 40+ yrs as i am not even 30 yet haha


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I'm no expert on compressors, but my first thought is that maybe the second stage valves aren't holding the air from going back to the first stage.
Just a guess on my part, but maybe something to check into.

Greg Mosley

Greetings 84prerunner, I have one. Used on locos years ago. Good unit. A few trinkets left out there for it. I believe Marcuse and Sons out of Texas sells valve kits. Enuf Said.

Mark Dieckmann

Is there a relief valve on the intercooler? If so what is it set at? It usually would be marked on it. Knowing what the relief is set at would give you an idea of what the pressure should be.


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You should think about a hydro test for the tank. Maybe I'm paranoid, but old compressor tanks make me nervous. If it sat for a long time with water in the bottom, it could have a problem...a little roll-around compressor tank made a hole through the wall of my uncle's shop. A 50 gal. could be a pretty big bomb.
Not familiar with that particular pump, I have a I-R 5 HP. Keeps up with a bead blaster just fine.


Thanks for the replies guys!

I have pulled the valves out of this thing and cleaned them before, they appear to be in good working conditions. However the brass crush washer seat in the head looks pretty beat up. Might pull those out and see if I can source some locally.

This unit does not have a relief valve between the stages. It had a capped port which I put the pressure gauge in.

This tank is not as old as the compressor, however still old. From the late 60s or 70s. I am sure a hydro test would be a great idea but I still tust it. It is an extremely heavy tank, tag says it's all 3/16" steel. Much thicker than many tanks I have seen. I also don't get much rust out of the drain. The relay in my phase converter stuck one time and it reached 180-190 psi before I realized and shut it off. If it was going to blow I think it would have then. I have it set to kick off at 135 currently.

Basically what it comes down to is I am just trying to figure out if 10-12cfm is about all I should expect out of this pump at 750rpm or if that seems low. Also, anyway to diagnose worn rings without a tear down?


Figured id give a quick update for anyone that cares. Haven't done anything to the compressor itself other than use it. Just got a cheapy VFD phase converter to replace the 30yr old static converter my dad built. got it hooked up good enough for testing purposes and decided to take a video.