Quincy compressor question

[Jake]

I thought I had a Quincy model 216 compressor for the last 30 years, turns out it is a model 325, much bigger. I posted here a few weeks ago asking some questions about it. It is getting weaker and leaking oil out the air cleaner. I took it apart and bought a head kit for it, new springs and seals and gaskets. I put it back together and it is no better. I am getting some exhaust out of the air cleaner. If it was a car I would know what to do but I am stumped here. Does anyone have any ideas? thanks, Jake

[Phil V]

The model 325 is twice the compressor of the 216 (literally). Your 325 should have a hydraulic unloader, is it possible the that could be leaking oil into your intake ? Also there is a crank case breather tube that ports into the intake section of of the compressor head. Its very possible that the compressor piston rings are worn out or possibly a cracked ring which will allow blow-by pressure past the rings into the crankcase. That pressure in the crank case mixes with crank case oil and comes out the crankcase breather tube as an oil myst.

I have a Model 325 Quincy compressor that I've been using just about every day since 1984 when I bought it new. It still works flawlessly today as it did the first day I hooked it up in my shop.

[Jake]

I used to use this compressor for sandblasting and it would keep up with no problem. It has been getting weak for a few years now. I am also only turning it at about 650 rpm's. I had the head off and the cylinders look good, no scratchs and the piston fits tight, no ridge on the cylinder so I don't think there is a problem there. I think the problem is with the exhaust coming out the air cleaner. It has the air unloader instead of the hydraulic. This unit was set up for mobile sandblasting, mounted in a truck. The truck burned to the ground. The valve unloaders, and side plate both melted off the compressor. I tried to buy it from the junk yard where it was at and the guy told me it was junk. He finally told me to get it out of his way. I spent about $25 on it and have been using it for about 30 years now. I guess I have got my moneys worth out of it but I am hoping to save it. Any idea what a new 325 pump would cost?

[Phil V]

Jake, I talked to two different Quincy repair techs this morning on the phone and they both agreed that your compressor problem is most likely the piston rings.

[Jake]

Hey Phil, Thanks for checking for me. I am sure the techs know what they are talking about but I do still have a couple questions. I was just playing with the compressor. It is a 30 gallon tank and it took 1 min 45 sec to reach 110 psi. It then took another 2 minutes to reach 125psi. One thing I did notice is that when the unloaders kick in and it is running in free mode that it exhaust out the air cleaner. Is this correct or is that part of the problem. Thanks, Jake

[racepaint]

Hi Jake,
Couple of things,,,several years ago my son who owns a commercial shop purchased a brand new 325 (pump only) in Denver for $1200.00. I also own a 325 and if I remember correctly it takes 12-15 psi oil pressure to keep the unloaders in,,my experience with an older 325 was the oil pressure may be a problem due to oil pump, leaks etc,,,I also believe when it unloads it hold the valves open so air would come out the intake because the valve is open,,,this is how they vent the pressure,,,I called Quincy customer service one time while rebuilding an older 325 and they were super,,stepped me thru the process,,they really know this pump so give them a call...Phil is right, it is about impossible to kill a 325 pump and it is completely rebuildable,,
Jim

[Jake]

Thanks Jim, I will give them a call. I knew the air had to go somewhere when the unloaders kicked in. I think the unloaders are working properly, but they could be opening particially. John

[Phil V]

My 5 hp, 80 gallon 325 pump Quincy took 5 minutes and 25 seconds to go from an empty tank to shut off at 155 psi (checked it this evening). I checked it also about 5 years ago but I can't remember how long it took then to build up to full pressure.

[racepaint]

Jake,
Another misc fact I found is the pump RPM from the factory is 790 rpm...I think at that rpm is produces 17.5 CFM at 175 psi...
Jim