Quincy 5120 HELP??(Roger are you there)

Thanks in advance for any help!!
GOD bless
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I am not sure what you mean by breather. If you are referring to the air filter, then you likely have an unloader issue, as the air being dumped by the unloader is often sent back into the head just behind the air filter. What I would do,is make absolutely sure that there is oil pressure, then, if there is, remove the unloader signal line which goes from the hydralic unloader valve to the head unloader towers. If there is air coming out while the compressor is running with proper oil pressure, the hydraulic unloader valve is faulty. It could be that it needs the seals replaced, since if they fail, it will not actuate properly, and there is a distinct possibility that the air signal is leaking into the crankcase, which would explain why there is oil and air coming out of the crankcase breather tube. Hopefully, all the air lines are hooked up correctly to the various controls, as it will be difficult to explain their proper routing to you. Ensure that there are no stuck rings. Ensure that the oil level isn't too high. Make sure that the unloader plungers are not seized down inside the unloader towers due to corrosion of the aluminum body of the unloaders. Take off the hexagonal covers, remove the rubber diaphragms, remove the metal puck inside and physically push down on the top of the plungers. They should go down relatively easily (the springs are a bit strong, but manageable) and they should come back up quickly, with no dragging or hesitation. Make sure that the 1/4"NPT openings on the side of the unloader towers are not obstructed, since that is where it vents the air it is trying to unload. If these ports are blocked, or if tubes attached to them are blocked, you will have unpredictable unloading. It is possible that the valve discs are cracked, but I'd exhaust every avenue of investgation regarding the unloaders before opening up the heads. There is the possiblity that there is also some debris on a valve seat holding open a valve (carbon from an intercooler is often the culprit here).

The braided stainless hose is often available from a hydraulic supply shop. If the ends are screwed on, it's possible to salvage the fittings and make your own, if you can buy the line in bulk. It's good stuff, but expensive. The fittings are removable, like the kind you see on one-wire braided hydraulic hose, except there is no left handed thread, if I remember correctly.

As far as the unloader towers go, make sure that the small hole drilled into the casing underneath the diapraghm is free and clear to allow the disphragm to move properly. It is near the top of the unloader tower "stalk", just under where it flares out to its full width.

The beauty of a Quincy, or most any other quality compressor, is that you can pull the valves without disturbing head gaskets. If you want to check the condition of the valves, simply unscrew the unloader tower, back off the locking ring underneath it (don't lose the sealing ring), then undo the four bolts holding the cap on. The valves will pull straight out of the head. You will soon see if there is carbon build up, broken springs or rust preventing proper operation of the valve assembly. You can fill each valve with varsol and see how quickly it runs out (if at all). More than likely you can lap the valves by hand on a piece of glass with some sticky backed air sander paper and some valve grinding compound. You can lap the discs in a similar manner. Free up any stuck unloader springs and pins while you are in there. It's all very easy to keep track of, each component is very different from the others, just do a valve at a time. Quincy valves and discs are quite sturdy and can often be rehabilitated quite effectively, although I simply replaced them when doing customer units. If you can do this, you will simply need to replace the small gaskets under each valve cover, or make them yourself (easy job with a ball pein hammer and some hole punches). It's well worth the effort before sinking $500 into parts. While you have everything apart, check the silicone o-rings which are embedded in the top of the plungers. These must be in good shape, as they seal in the air when the unloaders retract. If these are in bad shape, you will always leak air out of the towers. Make sure the surface they seat against is not rusted or eroded in any way.

Depending on the length of run, and what you need the air for, you might be ok with 1" pipe, but only for a reasonably short run. I would go with the biggest pipe I could when joining the tanks together. Persoanlly, my opinion on piping is that you should use the largest diameter you can comfortably afford, since it will get expensive to redo it if it doesn't do the job.

I have 3 Quincy air compressors: a 230 that's a 1935 model, a 310 and a 325. I love Quincy compressors!! I rebuilt my 310 and the 230 and have had the valves out of my 325, It looked like the o-rings were ok at the time, but it has been a little while?

Thanks again for all your help.Please be patient and don't quit helping, until I at least find a manual.Do you know where I can get a REAL manual, you know a book you can hold in your hands? I really don't want a cd rom.
Thanks again. and GOD bless

The 325 taking time to load up indicates either a slow build up in oil pressure,low oil level or a hydralic unloader with weak seals. I'd suspect the silicone o-rings last of all.

The cut-out pressure is determined by the pressure rating of the tank, and the amp draw of the motor at cutout. If the tank is good to 200psi working pressure, and the motor is sheaved properly to prevent excessive amp draw, and the relief valves are good for it, I'd say 150psi is fine. The guy you talked to might have mixed it up with the Quincy 4140 (?) which looks almost identical, but is single stage. If you have to resheave the motor to get the amp draw reasonable, you might be trading air volume for pressure, which may be counterproductive. Kinda like puting a rear end good for 200mph in a Powerstroke diesel meant to haul a horse trailer.

It works fine, and I set the psi up to 175 and no problems.It builds up to 175psi in about 3 1/2 minutes on a 200 gal. tank it sounds great, and no leaks!!! By the way I know I asked you before, but I forgot.What kind of oil should I use in this beast? and also my 325? Thanks and GOD bless you for all your help.

What do you think?
GOD blesss
Thanks again

Congratulations on the fix, you have a very nice machine there. If you are a couple of amps over on the motor I wouldn't sweat it too much.