Westinghouse 3YC Compressor

[nstei24]

Hello,
I am having issues with my compressor building pressure. It builds up to 20PSI and continues to run, but does not build. Earlier this fall I used it to fill my Tubliss system on my dirt bike to 100PSI, but didn't run it for several months after. I started it up to use it a few weeks ago again and am now having problems.
I took 3 of the 4 valves out and cleaned them. The mating surfaces were all clean when I took it apart. The other valve (stage 2 exhaust valve) is not coming out without a fight, but I took the head off and flipped it upside-down and tried the "holding liquid test" and it held liquid for several hours (extremely slow leak?).
Both of the head gaskets were in perfect condition when I took the heads off.
There isn't much of a filter(falling apart and needs replaced) so it is not like that is restricting air.
I topped off the oil reservoir, so that should be good
There is no leaking sound coming from either of the check valves
The biggest difference is that it was somewhat warm when I used it this fall, and it is currently 20 degrees in the unheated side of the garage, where the compressor lives. Would this cause any problems?
I am going to bring it into the heated side this weekend and see if that changes my results, and if not, it will at least be a little nicer to work on it
Any other ideas to test before sticking money into it?

 

[Stillgottimefor1]

A dry cold old belt will slip easily. That’s my bet. Nothing wrong with the pump. I have one of those waiting on me to finish up.[emoji106]


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[930dreamer]

Good looking compressor.

 

[Stillgottimefor1]

When it was running but not making over 20 was the electric motor slowing down? Wondering if the check valve in the tank is sealing well.


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[American Locomotive]

The other thing, is if it has a foam filter that is falling apart, you should get rid of it. No filter is better than chunks of foam getting sucked into the valves.

As others mentioned, I would be checking for leaks and slipping belts.

It would require simultaneous failure of valves in both stages to not get over 20 PSI.

 

[nstei24]

Thank you all for the suggestions. I went out and tightened the belts more, and took the air filter off completely(it is some sort of fabric?) without any change in results. The motor also doesn't seem to slow down any.
There must be a little leak somewhere because it was up around 20 psi last night, and then it was back to 0 when I got home again today, but nothing that I can hear if I turn the motor off and put my ear up to the compressor.

 

[MacMcMacmac]

Sounds like your unloader valve might be leaking while running. Since it dumps air into the crankcase you likely won't hear it. If you can pull off the copper line going to the back of the pump and seal up the port in the HP cylinder head that it comes from, you can test this theory by running it up with the port closed and see if it builds pressure normally. Since the unloader will be inoperable like this, do not restart the compressor before you take out the plug and reattach the copper line. If it runs normally, you will need to take out the valve and replace the seals in it, or replace the valve itself. There is also the possibility that the centrifugal unloader inside the crankcase has malfunctioned and is letting the valve remain open at all time which would have the same effect.

 

[nstei24]

I went and removed the copper line and the unloader valve looked pretty good, but I went ahead and cleaned it up anyway. I figured I would keep going since I had it that far apart and started to drain the oil so that I could remove the crank cover and check out the unloader inside the crank. Well, I took the drain plug out and found a nice chunk of ice inside, so I knew I had some problems.
Turns out there must have been enough water somewhere that froze and didn't allow something inside to open/close. I went ahead and brought it inside the heated side of the shop, drained the oil, cleaned out the sludge in the bottom of the compressor (I was told it had a fresh oil change when I purchased this early summer of 2020), and refilled the oil and now it works like it should! (well maybe a very small leak yet). I was able to get it up to 140psi pretty quickly before shutting it off for the night.
Thank you all for the help again, and thank you MacMcMacmac for pushing me further into the compressor.

 

[SVE Performance]

Have the same compressor the valves need to be lapped back in as I had the same problem and that is what fixed it .Parts are still available in the aftermarket including the filter material. Bill

 

[MacMcMacmac]

You are welcome. Something to remember when you have an unloader dumping inside the crankcase is that the condensed water vapor is getting blown in there too.