Quincy 325 Compressor help

[Brav]

Hi all. Just bought a new rig for my shop, and so far I love it. Ultra-quiet with respect to every other compressor I have heard. Its on an 80 gal horizontal tank with a 3hp new Baldor motor.

All seems to work well, but the oil pressure seems to be low when its running. I can't see where in the manual it states what the correct pressure should be. Oil level is on low side, but within the tolerances on the dipstick. I don't want to run it until I figure this out..

Additionally, is the port below the oil filter at the bottom of the crank case for draining the oil?

Also, any recommendation on oil brands?

 

[A_Pmech]

The QR-25 service manual says oil pressure should be 18-20PSI on compressors up to 250 PSI output pressure.

You can adjust the oil pressure with the oil pressure adjusting screw on the oil pump housing. It might have vibrated loose.

If the oil pressure adjusting screw locknut isn't loose, check the pressure gauge for accuracy before adjusting the pressure.

The pipe plug at the very bottom of the crankcase is the oil drain.

Quincy recommends 20W non-detergent oil between 32F and 80F (Quin-Cip brand of course)

 

[zkling]

X2 What AP said above. What ROC is your pump? With the filter it must be one of the newer units.

Quincy brand oil

 

[p0lar]

X2 What AP said above. What ROC is your pump? With the filter it must be one of the newer units.

Quincy brand oil

This, and what's really strange, is that they spec the same oil for compressors both with and without oil filters. What gives, Quincy?

 

[Brav]

Alright, we will check the gauge. It was bouncing a bit, so maybe it was low.

Also, after the tank fills and shuts off, there is a 1-2 second delay, then pressure is released from the oil pump housing, followed by the valve on the top of the second stage head.. is this normal? sounds like something equalizing.

I assume the bolt/lock nut just behind the gauge is to adjust pressure?

Pic attached. looks like previous owner put a nice handy oil drain feature.

What is ROC?

 

[zkling]

Wow, that looks nice, freshly painted too. Has it been rebuilt recently or what is the back story on it?

Also, after the tank fills and shuts off, there is a 1-2 second delay, then pressure is released from the oil pump housing, followed by the valve on the top of the second stage head.. is this normal? sounds like something equalizing.

Yes that is the unloader (tower looking thing on top of the head) doing their job. Yous is on the high pressure cylinder I believe. I am not too familiar with the 2 stage units, although they ain't much different. It should also sound different at startup, as in kinda loud like it is leaking air for 1-2 seconds then quiet down. Same thing the unloader allows the pump to gain speed and oil pressure before being worked to compress air into the tank. Quincy really thought of it all. I just love listening to them run.

What is ROC?

Stands for Record Of Change. Next to the model #/disp tag it should say R.O.C # or something like that, I kinda forget what exactly it looks like. Quincy has made those pumps for 50+ years, and along the way has added a few minor tweaks to it. The ROC helps to keep track of what the changes were and to find the applicable parts/manual for it.

One other thing you may want to check is pump RPM. Just measure the motor and pump pulley, check motor RPM and do the math. See where your RPM falls for your motor hp. Call quincy, they will send (email) you the performance curve for that pump and ROC.

 

[hofferwood]

Here's the ROC on mine-----yes it's a 1.

 

[p0lar]

Here's the ROC on mine-----yes it's a 1.

Whoa!!! I've got a ROC 7, November 12, 1959, in fantastic condition, but yours takes the cake! How did you get a ROC 1, and did you call Quincy to get its "born-on" date? They should happily oblige a small archive look-up.

The sound you hear is normal, BTW.