HELP please Quincy 325 roc12 reconditioned problems, NEED Quincy experts!!!

Join Date: Jun 2019
Location: Niles, MI
Posts: 8
Question Someone please help on my reconditioned Quincy 325
I purchased a Quincy 325 roc 12 about 2 years ago and I have spent over a year rebuilding this and it is done. I stripped all of it, including the tank to bare metal and painted and powder coated with HiTemp powder coat. Looks great. Bought the rebuild kit that included the rings, bearings all gaskets and valve seats with springs. All of the valves and unloaders are spotless and everything is torqued down correctly.
NOW my issue. I am trying it out and this is what happens. Starts normal, oil pressure goes to 25psi and 80 gallon tank fills slowly. btw I have dual unloaders and after about 7 minutes it hits 125psi then unloads down to 90. That seems pretty slow. Is that a reasonable time?
That is one question, now the above actions of the compressor changed after about an hour and a half of running it with the cycling on and off at the set pressure values.
Today I turn on the compressor, again after running it for only 90 minutes since the complete rebuild and what is happening now is not right at all and I don't know where to start troubleshooting,
Now after I turn it on, it starts building pressure, oil pressure goes to 30psi and then it keeps raising! It is building pressure like crazy in the crankcase and the oil gauge pegs clockwise all the way and when it builds to 125psi in the tank, it unloads down to 90psi, with oil psi still pegged, and when it goes to start building the pressure up again, the compressor stalls and will not allow the motor to spin causing it to lock up the motor...The 5hp new Baldor motor will keep stalling because I am not able to manually turn the compressor pulley!!! So, I shut the power off completely and manually release tank pressure and turn compressor back on, it is now unstalled and the motor starts up again.. When it starts again. Oil psi starts at 30psi and continues to climb to where the gauge is pegged then all of a sudden BANG!!!!!! the dipstick shoots out at rocket speed and strikes the air cleaner above it. Scared the holy crap out of me. Just had open heart surgery last year, so that didn't help.
After I composed myself, made sure I wasn't bleeding, and went in and changed my newly stained drawers.....I am asking the gurus.....What the crap might be happening???? It of course is not releasing pressure somewhere that was working before. I never changed the oil pressure setting, which was running around 25psi when the 325 was running correctly.
Has anybody had this happen on a 325 or understands the operation of a 325 enough to assist me? I would truly appreciate as I have spent over 150 hours reconditioning this compressor.

Thank you to all who might respond!!!

Find your local Quincy service center. Call them and speak with their service manager. He can answer your questions off the top of his head.

metalmagpie

I have three 5HP 325's. 7 minutes is way too long. 2 minutes maybe to hit 175 PSI.

Not sure how it's possible to put 150 hours into that, but if you did I'd sure think you'd have a first class understanding of how it works no?

loosen unloader lines, troubleshoot with common sense. Sounds like the unloader valve is jacked up.

If it launched the dipstick out you got something really wrong in there. The crankcase vents to the intake. If you have pressure building in the crankcase you got serious issues.

Garwood said:

I have three 5HP 325's. 7 minutes is way too long. 2 minutes maybe to hit 175 PSI.

Not sure how it's possible to put 150 hours into that, but if you did I'd sure think you'd have a first class understanding of how it works no?

loosen unloader lines, troubleshoot with common sense. Sounds like the unloader valve is jacked up.

If it launched the dipstick out you got something really wrong in there. The crankcase vents to the intake. If you have pressure building in the crankcase you got serious issues.

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Thank you for your condescending response.
If you have (3) 325's you should be telling me exactly what's going on....I would use common sense if I knew exactly how the unloader valves work with the hydraulic unloader. Not much to get wrong with the unloader valves. They are both spotless and have a small amount of lithium grease in them around the pistons. Both have new pistons and valve disks, valve seat gaskets,valve cover gaskets, valve springs, unloader diaphragms. Do you think that the hydraulic unloader is failing. I just took it apart and it looks like the top pistons has rub marks where the rubber seal has deteorated and got to the side of it. I just ordered a whole new hydraulic unloader instead of just rebuilding it.....what are your thoughts if I could ask?

Fishbyte said:

Thank you for your condescending response.
If you have (3) 325's you should be telling me exactly what's going on....I would use common sense if I knew exactly how the unloader valves work with the hydraulic unloader. Not much to get wrong with the unloader valves. They are both spotless and have a small amount of lithium grease in them around the pistons. Both have new pistons and valve disks, valve seat gaskets,valve cover gaskets, valve springs, unloader diaphragms. Do you think that the hydraulic unloader is failing. I just took it apart and it looks like the top pistons has rub marks where the rubber seal has deteorated and got to the side of it. I just ordered a whole new hydraulic unloader instead of just rebuilding it.....what are your thoughts if I could ask?

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GiGo…..You want an exact answer ? You expect Garwood to take time to walk you thru a whole rebuild ?

How much have you paid for this advice ?

If it is pressurizing the crankcase, you may have a piston ring or cylinder wall problem. Try leaving the dipstick out and see what happens.

Thank you eKrets! when I rebuilt it the cylinder walls looked excellent but I still honed them and replaced all new rings and checked and rechecked order and position of each ring. If the new hydraulic unloader does not do the trick, I will probably take head back off and check for cylinder wall issues, Thanks again for your help.

digger doug said:

GiGo…..You want an exact answer ? You expect Garwood to take time to walk you thru a whole rebuild ?

How much have you paid for this advice ?

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You nailed it Digger!!! I want him to walk me through a whole rebuild. I was hoping you couldn't see thru that. IF,you can't notice the sarcasm that I responded to his degrading comment then I apologize. Does he need your defense? Should I have paid him for his advice so far? If so please bill me.

Fishbyte said:

You nailed it Digger!!! I want him to walk me through a whole rebuild. I was hoping you couldn't see thru that. IF,you can't notice the sarcasm that I responded to his degrading comment then I apologize. Does he need your defense? Should I have paid him for his advice so far? If so please bill me.

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Lighten up, Fishbyte! YOU know what you did on the rebuild but nobody here was looking over your shoulder every step of the way so they have no idea what you did or didn't do or what you might have screwed up. Asking them to diagnose something that shouldn't be happening without any knowledge of your specific compressor isn't quite like throwing darts, but almost.

If you get a suggestion here that leads you to exactly what needs to be done you'll be damn lucky and should be grateful. In the meantime, take a step back, listen to suggestions, provide pictures where appropriate and work through the possibilities.

There are some serious abnormalities there so there may be more than one problem and one quick hit answer may be out of the question. The crankcase shouldn't be pressurized. The oil pressure shouldn't peg the gauge. I don't see a logical connection between those so there may be several things to sort through.

Good luck, Mr. Phelps.

TGTool said:

There are some serious abnormalities there so there may be more than one problem and one quick hit answer may be out of the question. The crankcase shouldn't be pressurized. The oil pressure shouldn't peg the gauge. I don't see a logical connection between those so there may be several things to sort through.

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I'm thinking that if crankcase is getting pressurized, that pressure is going to act on the oil in the sump and push it into pump under pressure. As the oil exits the crank, since crankcase is pressurized, the pressure is pushing back on the oil. What happens to oil pressure when crankcase pressure is relieved?

I suspect issues with secondary cylinder.

It is pumping slow and crankcase is pressurized.

Primary is pumping air into the secondary and it can flow through to tank but also into crankcase.

Bad rings or gaps in wrong place or something in the unloader where the air pressure can leak into the oil system.

Stop and troubleshoot.

Remove the air line between 1 and 2 and fire it up to see if oil pressure is right.

If you have another compressor then use it to pressurized this one via the intake and look for leaks.

Take simple single steps to look for problems.

We thinks you are leaking unloader plunger back into the oil system.

Sent from my SAMSUNG-SM-G930A using Tapatalk

Fishbyte said:

Thank you for your condescending response.
If you have (3) 325's you should be telling me exactly what's going on....I would use common sense if I knew exactly how the unloader valves work with the hydraulic unloader. Not much to get wrong with the unloader valves. They are both spotless and have a small amount of lithium grease in them around the pistons. Both have new pistons and valve disks, valve seat gaskets,valve cover gaskets, valve springs, unloader diaphragms. Do you think that the hydraulic unloader is failing. I just took it apart and it looks like the top pistons has rub marks where the rubber seal has deteorated and got to the side of it. I just ordered a whole new hydraulic unloader instead of just rebuilding it.....what are your thoughts if I could ask?

Click to expand...

I can't really follow what the hell you're talking about here.

The compressor in your picture is a real old one with the most basic style of hydraulic only unloader. The "unloader valve" I speak of is the damn valve on the side of the crank case. The "unloader diaphragms" are what actuate the intake valves and are most certainly not valves, they are just diaphragms.

I would struggle to see how the crankcase could pressurize past a few PSI. For one, it has a hard line venting it to the intake manifold and two, the dipstick just sits in there with an O-ring seal. A few PSI would pop the dipstick right out.

The only path between high pressure air and the oil PSI gauge is the unloader valve.

When I troubleshoot a QR quincy (it's 99% chance to be a leaky unloader diaphragm or crusty valves) I crack unloader lines and bypass the unloader valves if needed. Real easy to do. Hell, you can disconnect the unloader valve 100% and use a hand air nozzle with a rubber tip to pressurize the unloader diaphragms and manually check operation. You can even do the unloaders one at a time that way.