Quincy 310 compressor unloader valve

[kevs79]

I can hear/feel air coming out from under the unloader from the little ports while the compressor is pumping. Not as much as when it stops and relieves pressure, but some. Is this normal?
Thanks in advance for any advice!

 

[DerekV]

The unloader valve should only let air out when the pressure switch switches off, either automatically or manually. It sounds like you have a leak. You can confirm this by spraying soapy water on that connection/area (and do so carefully if it's near electrical connections) and look for bubbles while it's running.

 

[kevs79]

The air is definitely coming from the little ports under the value. Must be something internally not sealing. Like I said it's not a lot but can hear it while running. I wonder if there is some adjustment to the centrifugal "switch"

 

[American Locomotive]

Doesn't that use hydraulic pressure from the oil pump to actuate the unloaders? If so, I'd suspect the unloader just needs to be rebuilt.

 

[kevs79]

No this is an older one that has a centrifugal piece on the block that sends pressure to the valve. The later ones have the pressure switch of some sort.. This one is not pressurized oiling.

 

[American Locomotive]

Can you take a picture? I'm pretty sure all Quincy 310s have pressurized lube and hydraulic unloaders. Unless you mean by "older", you mean positively ancient.

In which case, the same thing still applies, you probably need to rebuild the unloader.

 

[The Tool Tyrant]

Kevs, Take a look at the 310 parts manuals listed here on the quincy site, oldest being circa 1950 and see if you can spot the correct record of change (ROC). FYI, all are pressure lubricated. Just because yours may not have an oil filter, does not mean it's not pressure lubricated.

http://www.revbase.com/aspx/UserJump.aspx#

Highlight 'Parts Manuals' and add keyword '310' when it opens go to page 2 and scroll to the bottom of the page for the oldest manuals.

 

[kevs79]

I had looked it up when I got it and it was splash oiling up until ROC 20 and that is when it changed to pressure oiling. Mine is ROC 10 so is splash oiling and the three way valve is controlled by centrifugal arms inside to open/shut the unloader. When I get some time I might take the unloader apart and see what it needs. It works pretty good now and seems to pump up fine but would do better if that unloader wasn't relieving pressure while it was pumping of course. Here is a picture of mine.

 

[American Locomotive]

Hopefully an unloader rebuild kit is available!

 

[Farmall 1066]

I've got an early, splash oiled 310.
Never needed parts, but from what I've heard, centrifugal unloaded parts are NLA.

 

[American Locomotive]

In this case, I'm pretty sure all that matters is the unloaded valve itself on the head, and there's a good possibility that hasn't changed and parts are still available.

 

[kevs79]

Well, I think I fixed it. I figured I would try to shoot some WD-40 into the little ports on the unloader and see if it would free something up or take care of some rust in there. Let is soak a while and fired it up and no air escaping! Who knows how long it will last but seems to be fixed for now.
I figured the CFM during an on/off cycle and shows to be 11cfm. On at 120psi off at 150psi, 60 gallon tank. Takes 1 1/2 minutes. Seems kind of high considering I am only running a 2hp motor and pump is running around 600rpm but I'm happy!

 

[The Tool Tyrant]

I had looked it up when I got it and it was splash oiling up until ROC 20 and that is when it changed to pressure oiling. Mine is ROC 10 so is splash oiling and the three way valve is controlled by centrifugal arms inside to open/shut the unloader. When I get some time I might take the unloader apart and see what it needs. It works pretty good now and seems to pump up fine but would do better if that unloader wasn't relieving pressure while it was pumping of course. Here is a picture of mine.

I stand corrected.