So I finally finished rebuilding my quincy 310 compressor. Problem is, it constantly blows air out of the unloader tower hole when its running. The oil pressure is set at 20, and adjusts just fine from zero to thirty. My thoughts are that the unloader mechanism is not closing , just constantly applying pressure to the diaphragm. I don't know how to check that. My other thought is the seal on the unloader pin inside the valve is worn, but it looks fine. It's blowing a Ton of air out of that hole. Help! I don't have much more money to dump in this thing.....
Quincy help!
- Thread starter mrpizza
- Start date
metaldad
Well-known member
A) oil pressure closes the unloader mechanism. there should be no air to the top of the tower when running with 20# oil..
air blowing out from under - bad diaphragm. or bad seat.
B) pressurizing c.c. - you have a discharge valve not seating closed. if it is a 2 stage, it's the low stage.
air blowing out from under - bad diaphragm. or bad seat.
B) pressurizing c.c. - you have a discharge valve not seating closed. if it is a 2 stage, it's the low stage.
metaldad
Well-known member
the line on the top of your tower should be hi pressure from your receiver. oil pressure closes the valve that feeds that air to the tower and bleeds it off, taking the pressure off the top of the diaphragm, allowing the brass push rod to rise, allowing the discharge valve to close.
if the air stays on top of the diaphragm, you wont load, and - yep, you may pressurize the case.
I'm going off memory, and that memory is from Qwincy 390's
if the air stays on top of the diaphragm, you wont load, and - yep, you may pressurize the case.
I'm going off memory, and that memory is from Qwincy 390's
metaldad
Well-known member
damn connection timed out
never mind, it posted
never mind, it posted
The line on top goes from the receiver tank through a t to the unloader mechanism on the side and straight to the diaphragm on top. I took the line off at the top of the unloader tower while it was running and sure enough it is constantly blowing pressure into the top of the unloader tower. So I guess it's time to rebuild the unloader mechanism? It still pumps up to 140 psi and then shuts off like it should, then kicks back on around 115. I imagine it will pump up much faster with this issue fixed.
Here are a couple of questions I have though:
One, how does the air pressure on top of the diaphragm bleed off once the valve closes from oil pressure and then take pressure off the pin?
I assume the crankcase is pressurizing due to a problem with the breather? I figure it should allow air to flow from the crank case to the head, not the other way around. How do I remove that to check it? I don't want to smash anything up.
So I think I am to the point where I need to rebuild the unloader valve, but not sure about the components in the unloader tower. Any more help and insight is greatly appreciated.
Here are a couple of questions I have though:
One, how does the air pressure on top of the diaphragm bleed off once the valve closes from oil pressure and then take pressure off the pin?
I assume the crankcase is pressurizing due to a problem with the breather? I figure it should allow air to flow from the crank case to the head, not the other way around. How do I remove that to check it? I don't want to smash anything up.
So I think I am to the point where I need to rebuild the unloader valve, but not sure about the components in the unloader tower. Any more help and insight is greatly appreciated.
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Bump for the morning crowd.
If I were to say f-it and sell this thing, what would be an appropriate asking price? An unloader rebuild kit is about 27-30 bucks per my local air dealer.
Here is a pic, all nice and shiny and rebuilt
Untitled by milesvdustin, on Flickr
If I were to say f-it and sell this thing, what would be an appropriate asking price? An unloader rebuild kit is about 27-30 bucks per my local air dealer.
Here is a pic, all nice and shiny and rebuilt
Untitled by milesvdustin, on Flickr
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I took the valves apart again and lapped the seats and all, they looked good before but now I know they are solid. My unloader mechanism seems to be toast. When I actuate it by hand, i can still blow air through it. It does get a little tougher like it is trying to work, but doesn't quite seal up. So that is why it unloads constantly. I need to run it up and see if the valve is actually sealing in the head and the disc on the seat to see if that fixed my problem with the air coming back through the unloader tower.
I lapped with 220 grit, should I go higher, like 600 or 800?
I lapped with 220 grit, should I go higher, like 600 or 800?
When I lapped my valves I went to 1500 and they looked great, and they work great too. Might want to lap them some more, but that will not fix your unloader problem. I picked up an extra (new in the box) unloader tower off e-bay to take parts off if I ever needed them and it wasn't very $$$ you might check it out if you have the time to get one that way.
Also if your unloader is unloading all the time it will not pump up at all, the pump when unloaded doesn't put out any air. You line from the pressure valve should not be sending air to the unloader tower/s when you have oil pressure, if it is its either not working or you don't have oil pressure!!
William
Also if your unloader is unloading all the time it will not pump up at all, the pump when unloaded doesn't put out any air. You line from the pressure valve should not be sending air to the unloader tower/s when you have oil pressure, if it is its either not working or you don't have oil pressure!!
William
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It still pumps up to 140psi then shuts off, albeit a little slow. It consistently lets air out of the hole on the unloader tower while pumping up. I think it still pumps up because the valve does close a little, so full pressure doesnt make it to the unloader at all times, but a little does constantly. I am pretty dang certain I have oil pressure, tons of flow out of the pump and it reads 20 pounds, I can adjust that higher or lower with the screw easily. Its not the unloader tower that is toast, its the mechanism on the side of the crankcase. I pull it apart like it would move when pressurized, and it still allows air through the valve. I will take them apart and lap them on some 1000 or 1500, I'll see what the auto parts store has.
Lapping the valves glass smooth should fix the air coming back through the head to the unloader, right?
Lapping the valves glass smooth should fix the air coming back through the head to the unloader, right?
WhoWhatNow
Well-known member
Very nice job on the compressor. Don’t stop now you are almost there.
A request: can you take a few post a few pics when you take it apart again? I have a 325 pump that I am going to start cleaning up soon. When I turn the pump manually the crankcase is pressurized so I may have the same problem as you. Thanks!
A request: can you take a few post a few pics when you take it apart again? I have a 325 pump that I am going to start cleaning up soon. When I turn the pump manually the crankcase is pressurized so I may have the same problem as you. Thanks!
This has a different valve setup than the 325, but I will post a few pics here after work. I know I am almost there, its just making me so mad I am about to sell it and get a brand new compressor. I think I should have from the start....
I think the crankcase is pressurizing due to the breather check valve maybe having some junk in it. I am going to pull the line and clean that out tonight as well. That breather feeds right into the intake, so when the pump is running the breather has air pressure into it. The check valve there should keep the pressure out of the crankcase. I think mine is plugged, so direct pressure to the case.
Not sure how the breather assembly comes out, I imagine it is press fit or it screws in.
I think the crankcase is pressurizing due to the breather check valve maybe having some junk in it. I am going to pull the line and clean that out tonight as well. That breather feeds right into the intake, so when the pump is running the breather has air pressure into it. The check valve there should keep the pressure out of the crankcase. I think mine is plugged, so direct pressure to the case.
Not sure how the breather assembly comes out, I imagine it is press fit or it screws in.
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metaldad
Well-known member
not necessarily. i'll take one of my 390's apart manana to see. you're not seating properly.
and with the unloader, I have a small bulletin - which comes in the package with a new one, about how you're not supposed to disturb the nut on it.
with your previous question, on the 'run' cycle, oil pressure will close the hi pressure to the unloader tower, and bleed it thru a tiny port on the base of the oil switch.
I went ahead and re-did the valves all the way up to 1500 grit, and they pass the water test now. My suction valves were terrible, and the discharge ones were so-so. They are mirror shiny now.
What do you mean not "seating properly?" The valve discs? The valve body itself? I have new seals for the valve body in the head. I finished all the valves tonight, tomorrow evening I will put it back together and give it a run test.
I would certainly like the information on that bulletin you have. I took my unloader apart, its just a tiny spring with a ball in one end, and then some springs and rods in the other. I didn't take that side apart.
I had a lengthy conversation with the quincy guys on the phone today. He said the valve discs not sealing will cause air to leak back through the high pressure discharge valve, through the cylinder, and then up through the high pressure intake valve. He agreed that the unloader was different problem on itself, and the crankcase is another. I think my ball valve was just dirty in my crankcase. I think (hope) I have fixed the valves, and will work on the unloader issue after I see this information if you still have that bulletin. Thanks!!!!!!!
Oh, I didn't think to take pictures, I was too busy working on it. The valves are still out of the low pressure side, so Ill take a pic tomorrow.
What do you mean not "seating properly?" The valve discs? The valve body itself? I have new seals for the valve body in the head. I finished all the valves tonight, tomorrow evening I will put it back together and give it a run test.
I would certainly like the information on that bulletin you have. I took my unloader apart, its just a tiny spring with a ball in one end, and then some springs and rods in the other. I didn't take that side apart.
I had a lengthy conversation with the quincy guys on the phone today. He said the valve discs not sealing will cause air to leak back through the high pressure discharge valve, through the cylinder, and then up through the high pressure intake valve. He agreed that the unloader was different problem on itself, and the crankcase is another. I think my ball valve was just dirty in my crankcase. I think (hope) I have fixed the valves, and will work on the unloader issue after I see this information if you still have that bulletin. Thanks!!!!!!!
Oh, I didn't think to take pictures, I was too busy working on it. The valves are still out of the low pressure side, so Ill take a pic tomorrow.
When you pump up the tank and let it sit over night does it loose pressure? If not, it's not leaking on the high side exhaust valve. On these pumps there is no check valve on the discharge side and if your HS exhaust valve is leaking you will louse pressure in the tank as it bleeds off. I see that your pump has a completely different unloader control valve than my model 390 has ( LDV ), and so I'm not sure you setup has the hydraulic unloader control for the oil pressure or not? I assume it did/does but I have not see that style of control. Can you set you machine to run in "unloader" mode ie. continuous run mode with cut in and out of the unloader/s??
William....
William....
I can not set it up to run like that. It runs like this: When the tank is not being actively filled, the motor is off with the pressure switch. The unloader valve is open, allowing the tower to receive air pressure and unload the high pressure intake valve. Once the pressure in the tank gets low and the pressure switch kicks on, the motor starts, the pump makes oil pressure, unloader valve closes, high pressure side can make pressure now.
I have not tested the valves yet, but I know before the pressure was being let off so fast out of my tank that it would go from 140 (cutoff) to 115 (cut in) in about ten minutes. So I was losing a MASSIVE amount of air out of the unloader tower. The only way it got there was through both of the high pressure side valves (intake and discharge.) So, with both of those leaking water after a water test, I now have them both smooth as glass and not leaking a drop of water. I torqued the high pressure ones back down, still need to finish one of the low pressure side valves. The intake valves were really bad on both cylinders. Tomorrow I will run it and see if the valves still leak. Thanks for the tips, they are really helping. I am just a thorough person, so thats why I am dang near writing a self-help novel for the quincy 310!
Thanks again!
I have not tested the valves yet, but I know before the pressure was being let off so fast out of my tank that it would go from 140 (cutoff) to 115 (cut in) in about ten minutes. So I was losing a MASSIVE amount of air out of the unloader tower. The only way it got there was through both of the high pressure side valves (intake and discharge.) So, with both of those leaking water after a water test, I now have them both smooth as glass and not leaking a drop of water. I torqued the high pressure ones back down, still need to finish one of the low pressure side valves. The intake valves were really bad on both cylinders. Tomorrow I will run it and see if the valves still leak. Thanks for the tips, they are really helping. I am just a thorough person, so thats why I am dang near writing a self-help novel for the quincy 310!
Thanks again!
WhoWhatNow, here are a few pics of the valves in my 310. They are different than a 325 in almost every way.
Here are the high pressure valves (the high and low pressure actually are identical), Intake on left and discharge on right. The silver rings hold them down in the head. Of the four holes in the head, the two in the back are the high pressure valve holes, the front two are the low pressure. The intake holes are the left and the discharge are the right.
Untitled by milesvdustin, on Flickr
Here is the low pressure discharge valve fully seated and torqued in the head, without the cap that goes over the top.
Untitled by milesvdustin, on Flickr
And here is the high pressure intake valve. This is the valve the unloader setup goes over the top of this valve. Right now it is just the valve torqued down in the head.
Untitled by milesvdustin, on Flickr
Hopefully those can help you or someone else out. I got three valves completely passing the water test, one more to go. I can't believe how bad a few were. This should completely fix the leakdown issues.
Here are the high pressure valves (the high and low pressure actually are identical), Intake on left and discharge on right. The silver rings hold them down in the head. Of the four holes in the head, the two in the back are the high pressure valve holes, the front two are the low pressure. The intake holes are the left and the discharge are the right.
Untitled by milesvdustin, on Flickr
Here is the low pressure discharge valve fully seated and torqued in the head, without the cap that goes over the top.
Untitled by milesvdustin, on Flickr
And here is the high pressure intake valve. This is the valve the unloader setup goes over the top of this valve. Right now it is just the valve torqued down in the head.
Untitled by milesvdustin, on Flickr
Hopefully those can help you or someone else out. I got three valves completely passing the water test, one more to go. I can't believe how bad a few were. This should completely fix the leakdown issues.
WhoWhatNow
Well-known member
Thanks. Sounds like you almost have it figured out. I bet you will be happy you didn't throw in the towel after you are done. Once I start on mine I will post pics as well. If I have to tare the pump apart it will be cool to compare between the two designs.
metaldad
Well-known member
i'm not familiar with that one.
I am going to take it to the local guy and let him look at it. There are a lot of springs and ball bearings inside of it that I don't want to mess up. Didn't get a chance to work on it at all last night, my wife is getting sick of me being in the garage all the time.
turbosl2
Well-known member
I have the exact same compressor and maybe someone can lead me in the right direction.
The unit sat for a few years and when i started it up again it would not build ANY pressure. After taking the head apart and cleaning some things it now will only build 20psi.
So i just finished rebuilding everything (new rings, gaskets, valve discs, springs...etc). It still does the EXACT same thing, 20psi air.
I have about 15psi oil pressure, its always been at that.
Where i may be going wrong is the valves, what are you talking about when you mean lap them in? I have built many engines but these are just tin discs.
The valve splits in half and i just replaced the springs and tins. From what i read above is there a procedure to get these to seal, and i guess i should water test them.
Or are you referring to when the whole valve cartridge drops into the head. I have aluminum crush washers that seal the cartridge to the head.
Whats the torque on the threaded inserts that hold hte valve cartridge in.
I am not sure where i am going wrong but here is some more info.
The crossover tub in the back that is a heat exchanger, NEVER gets hot. The tube that fills the tank below gets warm, but not hot. How can i trouble shoot?
Thanks
-Tom
The unit sat for a few years and when i started it up again it would not build ANY pressure. After taking the head apart and cleaning some things it now will only build 20psi.
So i just finished rebuilding everything (new rings, gaskets, valve discs, springs...etc). It still does the EXACT same thing, 20psi air.
I have about 15psi oil pressure, its always been at that.
Where i may be going wrong is the valves, what are you talking about when you mean lap them in? I have built many engines but these are just tin discs.
The valve splits in half and i just replaced the springs and tins. From what i read above is there a procedure to get these to seal, and i guess i should water test them.
Or are you referring to when the whole valve cartridge drops into the head. I have aluminum crush washers that seal the cartridge to the head.
Whats the torque on the threaded inserts that hold hte valve cartridge in.
I am not sure where i am going wrong but here is some more info.
The crossover tub in the back that is a heat exchanger, NEVER gets hot. The tube that fills the tank below gets warm, but not hot. How can i trouble shoot?
Thanks
-Tom
Chris.Santamarina
Well-known member
Metaldad, here is my unloader. There is a nut that screws in to the hole on the top.
Untitled by milesvdustin, on Flickr
This is what is causing your problem. No adjustments are made on this unloader. It is what is referred to as the Hydraulic unloader. Make sure the 1/4" tubing is installed correctly. There is a R stamped on one side of the hydraulic unloader. The 1/4" tubing goes from the side marked R to the receiver tank. If your oil pump pressure is between 18-22 psi when the pump runs you should have no air going up to the unloader tower from the opposite port on the hydraulic unloader. The brass cap that you removed from the hydraulic unloader should of had a small ball and a pin, springs inside.
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turbosl2
Well-known member
I saw a youtube video of a guy rebuilding your style compressor (325 i think). He had the same unloader.
This is one of them, there was another that talks about the unloader
turbosl2
Well-known member
I just fiddled with my 310 compressor, the valves hold the water when i tested them. I upped the oil pressure to 20psi. It seems to be building pressure now, it made it to 140psi but took about 30-40mins. Seems VERY slow.
What i noticed.
-Seems very slow to build pressure for my tank, i think its a 60 or 80 gallon. I will have to measure it. But 30mins even seems long. How long are these things suppose to take?
-The head and cylinders do get hot, but the crossover pipe in the back stays room temp. Its a finned HX design and it never gets warm, so something is not working correct. I touched both sides where they bolt in the head, and it was room temp.
-If i pull the dipstick out, the dipstick will blow out then get sucked in as the compresssor works (i.e. blowby). It wont get pushed out once i push it all the way in, but with it out you can feel the air puff out with the strokes.
-It never shut off even at 140psi, i thought it was adjusted at 115, so maybe my pressure switch is stuck. I turned it off at 140 myself just to be safe
What i noticed.
-Seems very slow to build pressure for my tank, i think its a 60 or 80 gallon. I will have to measure it. But 30mins even seems long. How long are these things suppose to take?
-The head and cylinders do get hot, but the crossover pipe in the back stays room temp. Its a finned HX design and it never gets warm, so something is not working correct. I touched both sides where they bolt in the head, and it was room temp.
-If i pull the dipstick out, the dipstick will blow out then get sucked in as the compresssor works (i.e. blowby). It wont get pushed out once i push it all the way in, but with it out you can feel the air puff out with the strokes.
-It never shut off even at 140psi, i thought it was adjusted at 115, so maybe my pressure switch is stuck. I turned it off at 140 myself just to be safe