Hi. First off, I spent quite a while last night watching 7 or 8 of your Quincy 325 teardown and rebuild videos. For anybody interested in doing this, you have created an incredible resource. I am a little stunned in reading through your comments that this tjkslice character is razzing you all the time, and secondly, that years later you are still answering every question and trying to help everybody who posts comments. Every single person!!! I'm getting my first 325 now, it is an ROC 7 from 1957 or so, and I know I will have a lot of work to do on it, but I'm not sure I would have even wanted to take on the project at any price without having watched you explain exactly how they work and what is involved in restoring them to function properly. Thank you!
Hey, I just wanted to say THANK YOU for sharing your expertise in these videos. I've now rebuilt two Quincy compressors, a model 306 and a 240, using your approach. It would have been a hell of a lot more difficult without these tutorials.
Just wanted to say thanks for sharing your knowledge and nice presentation. It's not often you find a video from 2011 this well done and this useful. THANKS
They don't make um like they use to is a under statement. With that ole guy. She's now ready for another 50+ years of work. Terrific job rebuilding it. Not many people take the pains and care to do the job right as you do! Particularly impressed, with painting the inside of the case! Very Nice!!
Excellent series. I'm looking at buying my first two stage air compressor and trying to dig deeper for information. Wow, this was it! I appreciated the quality of work and knowledge you shared. Well done, and thank you for taking the time to document this rebuild so thoroughly.
Hey Dave !!! Man you did one fantastic job Brother !!! You have unleashed the Beast , for many more years of Service !!! You are a man very attentive to every last detail !!! Great job my Friend !!! I'm off to get Mom out of rehab , take care Dave !!!
Hello Dave, Thank You for the great videos. I just rebuilt the head on my 325 roc 7, and the hp discharge valve still leaks, but I just realized that I didn't lap the seats before I installed the new valve disks. I'm going to do it today and reassemble. I really appreciate you sharing your expertise.
Really enjoyed your videos and I think they were the most informative I've had the chance to ever watch on youtube!. Really learned a Great Deal that will more than likely carry over into other compressor projects I do off and on. Real Class Act and easy to watch when you know the person your watching knows all the trick from experiance!!
Thanks for the videos!! I rebuilt my 325 watching these. One thing I didn't hear you didn't mention how much oil pressure you should run on a 325. Also I have the older vane style oil pump and notice that it takes 10 seconds or so to get oil pressure.
I'm redoing a 325-16 and these have been very helpful. Thanks for the anti seize reminder. Scraping off the old gaskets was a pain. I immersed the head casting in Esprit rust remover and it made the inside clean up much easier. Dave
Now you really have my attention. Your video is great and now I firmly believe you are going to save me some money too. I did as instructed. Plugged it in, let it pump up to about 60psi, pulled the plug and in about 2 seconds I got the pfffffft sound and then the air started coming out of the tower bleed hole.
Fixed both valves and now it runs, sounds, acts and pumps like a new compressor. When I put my fingers over the inlet it runs almost silent and the oil pump stops reading pressure on the gauge. I can still feel a little air escaping out of the bleed hole on the tower after it shut off. Maybe the discs will wear in. Pumped to 160 before I unplugged it and did it pretty fast. Interstage operating right at 30psi now. Dave, thanks for all your help! I feel like I have a new compressor again.
Great video series on Quincy rebuilding. I have a couple Quincy 370's that need rebuilding and this video will help a lot. Also really like the video on the dual control installation, as I am planning to run one off of gas engine.
Appreciate your time in making the video.I still have 6 of these on campus (actually duplex style, so 12?), out of a total of 41 compressors total, and your video helped me in the task of working on rebuilding the valve components.Most of the Quincy units ,I have, are about 30 years old.
This has got to be the best sounding compressor I've ever heard. Thanks for the great videos. If I ever find one I'll get back to them for inspiration :-)
Thanks for the vid, I purchased a good used QR-25 from a screen print shop, all the paint is burned off the output valve and discharge line. It works great, nice spin on oil filter, found a napa cross over. My unloader unloads twice though, one short spit then a longer one with a quarter second pause in the middle.
Great series! Watching you let me know how little I know about restoration;-) I don't have anything like that, but it was cool to see it done rite.....
Dave, first of all thankyou to the nth degree for doing this series. Quincy is very tight with allowing quality service manuals to be published or shared. You have saved me and thousands of others, THANK YOU sir!!!! I just purchased a 325 ROC 12 and mine has the 2 unloader valves. It also has a middle area that I havent seen on any others. It is between the pump and the motor and it has a pipe coming off the compressor head and then a square set of cooling fins and then a larger pump type looking contraption that enters into the top middle of the tank.....Do you have any clue what that could be and what it does? I am just starting to gut the compressor and start the cleaning process. If you do not have time to answer, I more than understand. YOU ARE DA MAN!!!!!!! Thanks again for all your time and courteous help
Thanks for all the nice words Jim! That contraption you're referring to is what Quincy compressor named a cushion chamber, It's designed to take out the pulsation of the compressed air In hopes of making the whole compressor package quieter, A lot of the noise generated in a reciprocating compressor is through the discharge line, That pulsating compressed air entering the tank causes what's known as intank noise. The cushion chamber actually did work but there was one inherited flaw, They had a tendency to become log with oil and carbon, In some cases it would restrict the small tube that feeds the tank, There's also a relief valve located on the cushion chamber that had a tendency not to open or also become plug with carbon, I think you might know where I'm going with all this, What's your say a few of these cushion chambers exploded and therefore Quincy way back in the day discontinued to use of them, I would strongly suggest you just get rid of the thing and plum the discharge line straight into the tank hopefully there will be an opening somewhere that you can use. Good luck in the future!
@@rotarycomptech Thank you so much for replying, especially so quickly!!! Can I totally remove it from the tank and run plumb the discharge directly into the remaining hole, or is it too large?
@@rotarycomptech Since I will be using this compressor no more that 5 hours a week, Can I just focus on keeping that chamber cleaned out or would that still be too much of a risk? If so, Could I connect the discharge tube into one of the threaded end plugs? I have one at each end of the tank about 1/2 way up from the bottom. Sorry for the quantity of questions
I had a quick question, during the assembly, you mentioned and clearly demonstrated the discharge valve springs are painted white. According to the parts list, there is only one valve spring (Quincy part #7270) available for both intake and discharge valves. I recently purchased this valve spring and found it had no kind of paint or distinguishing markings.Is there a noticeable difference in size, shape, and or gauge between your white and unpainted springs is it safe to interchange part #7270?
I have a Quincy 320 - trying to setup for a friend but it has issues. It knocks a bit on startup (no air pressure) but stops once there is some pressure in the tank. Then when it gets to about 60 PSI, air starts coming out of the unloader valve. I've cleaned up the valves as best I can, new diaghram on the unloader but don't have the tools to go further. Thoughts? I have a Service Shop about 1.5 hour away.
I took the hydraulic un-loader line off of the tower and the bleed stopped leaking air. Put my finger over the copper line from the un-loader and it built up pressure. So I'm guessing the problem is the small valve at 12 o'clock on the oil pump that is fed by the copper line from the air tank and line going to un-loader tower?
Thanks again, the o-ring is still on the brass plunger and it's in good shape. After I put it all back together but before placing the rubber diaphragm in place I pressed down on the assembly with my finger and it felt sticky. It wasn't free like I think it should be. I'll take it apart again and see what I can see.
If let it pump just for a minute it gets up to 40psi or so and the pop off valve in the head starts leaking and drains the tank. Will a new PRV resolve this or is it indicative of something else going bad, i.e. diaphragm? Should I buy a head rebuild kit online and a new PRV and do what you did in this video? Will I need the spanner wrench and huge hex for the diaphragm tower?
Switched places with the tank pressure gauge and PRV. Interstage pressure appeared to register equal to tank pressure up to 100psi when the PRV popped and I unplugged the motor. Still getting pressure on the unloader line coming from the sensor on the oil pump when not running. Is that normal? No air escaping out of the intake filter inlet. That's a good thing!
I'm getting deeper into it and need more help. Earlier I said air was coming out of the PRV, it's not, it's coming from the bleed hole in the unloader tower. I pulled the diaphragm and it is not cracked or leaking. Visited my Quincy dealer. He wants $180 for a Head Overhaul Kit which includes gaskets, two different sets of springs, pins and springs, discs, and an oil pressure gauge. $13 for an oil filter. That seems high. Are the kits available on the internet reliable?
Just bought one of these QR-25 (325) compressors. Actually it is the second one. My dad had an old one but it has two diaphram towers on it. This one only has one. What's the difference? This newest one is a 1990's vintage. It needs some help and so do I. When I plug it in and and it starts pumping it seems slower to build pressure than it did when my company bought it new 23 years ago. Could the valves be causing this?
Okay, bought a head overhaul kit which is just gaskets, copper valve seats, diaphragm, valve discs and springs. When I took the valve covers off I noticed rust on all but the big cylinder intake side. One discharge valve is loose. The shoulder bolt will not tighten enough to draw up the bottom of the valve to the top. Maybe that is part of my problem? I have all the parts soaking in Evapo-Rust. Hope to assemble tomorrow. Can I put a washer under that shoulder bolt so it draws up tight?
I think your problem is the HP discharge valve when shut down does air escape from the inlet filter? does your machine have a interstage relief valve?...Can you shot a video of the compressor and it's related problems? It may be helpfull...Thanks Dave
I recently acquired a "Quincy 325-15" that appears to be in "like new " condition ( reportedly used in HVAC process control). Recently, it started blowing high pressure air out through the hole in the head unloader after establishing normal oil pressure during operation. I have not dissect the problem yet. Can this be a simple case of a torn diaphragm? Thanks for your time.......
Hi Dave, great vid series! You did a wonderful job documenting the rebuild process and diligently responded to commenters to provide additional info. Thanks! My question: Do you know the earliest 325 ROC number Quincy still supports with available replacement parts? Thanks in advance for your response!
your videos on this are Awesome. I picked up a 325-13, I just ran it for the first time, and when it shuts off it dumps all the tank air out of the un-loader port, if I unhook the un-loader tube there is a small amount of air coming out of it.
+ROTARYCOMPTECH Thank you' I will open it up and take a look, so a small amount of air will always come out of the hyd un-loader valve? who do you recommend for parts?
IBRACIN get your parts through a local Quincy distributor, the only time air will leak out of the hydraulic unloader is when there is an absence of oil pressure
+ROTARYCOMPTECH so I took apart the high pressure discharge valve , it was really gunked up, cleaned and reassembled, and that did fix the tank dumping at at very high rate. but it still leaks air from the hyd. unloader after it shuts off, to be clear I know its supposed to dump the head pressure after oil pressure goes away, and it does do that, but then it continues to slowly leak air... it looks like the sealing ring on the brass plunger is just really hard, is that a serviceable part, or do i have to buy a whole new unloader.? Thank you for your help.
+IBRACIN I REBUILT the valves, installed new kick off springs, and a new unloader piston, rebuilt the hyd. unloader... all is well except, after it cycles off it leaks air from the crankcase, its very small but still a leak. just wondering where to look to fix it?
I am considering buying a 80 gal 325-7 compressor. It was built in 1958. I saw a complete overhaul kit on ebay for $418 Is this a good way to go? PART: MOK 325-6-Q Quincy style overhaul kits have been assembled to include gasket kit, shims, piston pins (lock rings if used), piston ring kit, piston pin bushings, insert bearings (if used in original rods), main bearings, valve discs, springs, o-rings, oil seal and unloader diaphragms if required, to recondition one compressor.
Nice job, I had a quincy 325 and I traded a friend for a welding machine, he needs an electric motor, and I was wondering what motor you have on this compressor. thanks.
I can't win for losing. I had to replace the motor capacitors which is why the Mag starter burned up. Now I have done the head overhaul and the pop-off on the discharge side is popping off with each stroke at about 100 psi. I used a silcone spray to protect the cast iron valves. I wonder if it is sticking the disc to the valve? I noticed a slight nick on one of the discharge valves seat. I purposely put it on the big cylinder. What next? I will have a mint in this thing if I keep going.
thx and for the dismantling the unloader their are many types of unloader i'm asking about the one installed on the oil pump direct can you help me with this
Find out what the interstage pressure is when running should be around 45 psig also does the relief valve lift when off and W/ 100 psig in the tank? Iam trying to find out if it's a HP discharge or suction valve problem don't worry will get it right!
I just picked up a 70s 325. It accumulates water in the crankcase oil very quickly, I have to wipe it out with towels by pulling side plate. I had about 3/4” of white sludge in the bottom over a 3 month period. It runs maybe 3 to 4 times a day. Can you point me in a good direction. Also thank you so much for these videos.
Simply put your not running your air compressor enough and your ambient humidity is being collected in the crank case. It’s a common problem for people like yourself and me who only use their air compressor for short periods of time or not long enough to get the oil in the crank case up to temperature, after all this is what causes the moisture to flash off of the lubricant. You may try to install a crank case heater but in most cases it doesn’t work very effectively. If you don’t care about power cost and the compressor running you can always install a timer drain solenoid valve to drain the condensate from the tank and have it set to go off every couple of minutes for 20 seconds or so. In any case just like me you have to get in the habit of running the compressor up to temperature before you shut it down for a while
@@rotarycomptech really appreciate you answering my question especially on an old video! I was afraid that was the case. I’ll just keep an eye on it and change the oil once a month if need be. My tank leaks down over night so I drain it completely every day but it only takes 10 min to fill to 190 psi so it barely gets warm.
I find it simply amazing how many people you have helped, or given the "idea" to rebuild an old piece of history. I myself saw one of your videos and made it a point to go hunting for one. Night and day difference between the compressor that I had been using for the past 12 years. I found a 325-13 that ran great... however had been sitting for quite sometime. I tore it down to noting and pretty much followed your videos to the T. I am having one slight issue that I know you have addressed on here... The HP unloader tower leaks at the 1/8 npt hole. You have said that it is an issue with the valve assembly... however I am curious... how exactly? When I did my valves i started with 500 grit and worked up to 1200... extremely smooth with no imperfections at all. I really don't want to tear up the paint job... and know I could just add a check valve to resolve the issue... but I'm just curious what exactly would need done to fix this issue? The only thing I didn't replace that I probably should have was the brass plungers.... but from what i gather... that isn't my issue and I am just paranoid for no reason. A side note... has anyone told you that you sound JUST like Nicolas Cage?
It is only when it is off. I honestly had no idea it was leaking until it kicked on in the middle of the night. I sprayed down the very few fittings from the tank and found nothing... then I remembered seeing a video somewhere about one that had air leaking from the air filter (tower was plumbed to the top head port) obviously had a large leak. Thanks for all of the support you have given everyone.
can you give me advice on this. I just picked up a 325 ROC 104. Looks brand new but it seems the ropes that moved it dropped it and bent the crank pretty good. wobbles bad. can a machine shop straighten it. New crank is really pricey. Also there's an older Champion nearby that looks clean. Is the 325 a much better pump. I'm up for the work if its a better machine. Really a shame. Thing looked perfect.
I would check the interstage pressure when running should be around 45 PSIG and the relief valve should set for 90 #...If it lifts when running it's typically the HP inlet valve if it lifts after shut down it's the HP discharge valve in any rate it's a problem on the HP side.. A pipe wrench will work to remove the tower the hold down can be removed easier when removed if you don't have the tool
@oocheewalley I am not up to date on what record of change number determines the obsolete pumps, Does your pump look like mine does the head have round valve covers opposed to plates? does it have a oil pump? is the on loader on the side or on the front a k a 3 way valve or hydraulic unloader if none of this makes sense shoot a video of the compressor I will be more than happy to help you
Hey Jim, Sounds to me like your crankcase breather isn't working properly. There should be a 5/16 OD copper tube that runs from the crankcase opposit side of the hand whole cover To the intake portion of the head. From what you're describing it sounds like it's not venting. You can remove the line at the crank case to see if its operating some models had a tube that mount inside of the crankcase and inside of that tube was a plastic ball kind, It acts like pcv valve in a automobile. The motor stalling issue sounds more like a problem with the motor or the incoming voltage rather than the compressor but to confirm or deny there is an issue with pressure you may want to install a pressure gauge on the discharge line before it enters the tank to ensure you're not over pressurizing the compressor if you know what I mean there could be a restriction in the discharge line I think I remember you telling me this unit had the old style cushion chamber on it? Also if you have and amp meter check the amperage when the motor starts to bog down and also check the voltage it should not drop off by more than 2 or 3 Volts at the most. Good luck!!
ROTARYCOMPTECH, I have a new QR-25(325) and I just rebuilt the head watching your video(Thanks!). Compressor starts at 135#'s and stops at 180#'s, the run interval is right at 3min, how do I extend the run time? There is moisture rusting the valves.
I believe the discharge spring has a bit more tension than the suction.. But Iam not 100 percent on that. Quincy has a TH-cam channel they might answer that question for you, but thanks for asking
Is it absolutely necessary to prime the crankcase? Rebuilding a 210 unit and lost most of the original primer while cleaning it. Crank wasn't rusty at all. Is it to seal in the oil or to prevent rust?
@@rotarycomptech thanks for the reply. This whole series has been very helpful. I think I will take the chance of not priming it. Already tried some enamel but I didn't like how it was curing in there (didn't get all the oil out) so I stripped it clean again. For reference, what was the primer that you used?
Hey man thanks for posting the videos. I have just recently acquired a 325 ROC 12. I tried calling the only Quincy distributor in my state to get pricing on parts and the support tech said that "That compressor is no more than a boat anchor. I would be more than happy to set you with a new one." No thanks Can you tell me where you purchased your parts from, I would to get some reliable help? Thanks again
Good video. I am working on a project that perhaps you can help me on with some advise. I'm a HVAC heavy tonnage mechanic in the trade for 35 years. Been working on some high pressure refrigerant recovery units that can transfer around 1,000 to 2,000 pounds of R22 or R134a in a recovery tank. Been thinking about trying a quincy model 210 air compressor. What are your thoughts? Thanks
I saw you comment on another video on a 325 roc 7 that it is an obsolete model and parts are not available. is the ROC 7 different than this model? Thank you
@swasey1952 The tool is made by Snap-on the P/N is N6664 I don't know if it's a Quincy or a Snap-on P/N it maybe eather or? You might try to heating the the valve cover and try turning the hold down screw clock wise with a piece of angle iron
Very well put together and informative rebuild series. I am happy with the unique tips and tricks you've shared. I purchased a Quincy 5120 a couple of days ago. Upon first inspection I spun the flywheel to make sure it wasn't locked up. I noticed that only one head was giving a deep chug from the intake filter as I was turning it over by hand. Shouldn't both sides have a chug? It is an LS and I am wondering if the valves position of the dual control may affect what noise I heard from the one head.
dapaid1 Thanks for the comment, yes both cylinder Banks should have the same audible sound. If not more than likely the compressor has a stuck unloader piston or plunger causing the inlet valve to be open. Or worst case scenario it has a couple of broken connecting rods. I think I've rebuilt more of the 5120 model Quincy compressor than any of the other ones. In an odd way I miss those old days
dapaid1 the only difference between the 5105 and the 5120 is the crankshaft and the cylinders the only really way to tell without taking it apart is the the length of the cylinder
From what points do I take the measurement and what dimensions am I looking for? The inspection plate was replaced, as you will see when I post the video. I understand the roc may be stamped on the crank. Will it be visible if I open up the inspection plate cover?
dapaid1 the part number on the crankshaft will be different but I'm not so sure that you could see it from the inspection plate. on the cylinder itself where the bolt-holes fasten it to the crankcase on the 5120 model it's pretty beefy about 1 inch in diameter. on the 5105 it's about half the size or roughly a half an inch. I can't tell you the exact dimensions as I don't recall them and I don't know that they're published, it was just a visual familiarity with the two pumps sitting side by side.
@fastst1 the hydraulic unloader on your air compressor should be different then mine if your pump has the oil filter the hydraulic un loader should thread into the side of the oil pump housing a quarter inch line should run up to the on loader tower I would suggest you install a pressure gauge in that quarter inch line but don't remove it from the tower stop and start see if the pressure fluctuates
do you still remember any specs on this , I have one from 1975, motor ( electric) went bad, had some ppl mess with it who should not have and .... now I need to know clockwise or counter clock wish and the RPM I likes so I can replace the motor .. I through a cheap 2hp 1800 rpm one on there to make sure it still works, and it will build pressure both directions , but with the pully having "fan blades " on it im sure it ment to go a certain way .... thanks
There should be a directional arrow on the fly wheel itself. The older compressors with the old vane type oil pump will make oil pressure in either clockwise or counter clockwise rotation
I dont know but i dont have the part that u dismantled that have D side and R side my unloader tower is connected to a part attached to the oil pump and i need to dismantle
Your videos are great and really helped me rebuild my 325. Many thanks. Mine is running great but doesn't unload after stopping. When the oil pressure drops from 20 to zero I don't hear any hiss of air to unload the head. Also there is no air coming out of the (upper) port on the hyd. unloader when the unit is running, thus no air to the diaphragms, but the unit pumps air anyway....don't know how this could be. Any suggestions? Again, thanks for sharing your knowledge and expertise with so many watchers.....JF
it sounds like you have a bad hydraulic unloader when the compressor is running and has developed oil pressure the hydraulic unloader should close and remove the signal to the unloader tower diaphragm. you need an air signal to the diaphragms to unload the compressor not to load it up thanks for the comment !
ROTARYCOMPTECH Thanks, Dave, I can see that the hydraulic unloader piston sticks and doesn't open and close easily. Is it any big deal to rebuild this unit? does it just come apart after driving out the roll pin? Thanks again, and keep those Quincys chugging. JF
hey paul first thing try removing the quarter inch line that goes to the unloader tower when the compressor is running and has oil pressure there should not be a air signal second check to see if the unloader plunger still has the o ring on it also check to see if the piston underneath the diaphragm isn't rusted and stuck down if that's not it then the high pressure intake valve is stuck open it's not uncommon to see rust in the high pressure area causing parts to stick together
This videos are very helpful and I have almost completed rebuilding my 325. I have a question though. Would it be a bad idea to rotate the I high pressure side valves to the low pressure side and vice versa?
PracticalTactical typically the valves on the low pressure side are in better shape than the high-pressure ones and it's a good swap to go that direction especially for the discharge valves
Yes sir I figured that wouldn't be a bad idea. I really want to thank you for the time and effort you put toward putting these videos up and answering people's comments and everything. You have really been a great help and a good person!
Hey Chad to my knowledge Quincy doesn't offer a rebuild kit only individual parts at one time they had a head kit to rebuild the valves but i don't think they offer that any more it was called a VIP kit. The ACFM rating is around 18 SCFM. Good luck thanks for the comment
Thank you for making and uploading these informative videos. They were a big help in helping me rebuild my personal 325-13. I have a question for you. My rebuild turned out really well except for one thing, it will not unload. I disassembled and double checked the unloader tower and the brass unloader valve in the block and both seem to be fine except not only will it not unload, The oil pressure will not return to zero when the compressor is turned off. It hovers around seven psi. Any thoughts you might have what could be causing this and what I should look at next would be greatly appreciated. Best regards, Dave PS it always amazes me that no matter how good somebody tries to do by posting videos to help people they still attract trolls who have nothing better to do than to criticize them. I'm not sure if they do it because they're in that dire need of attention or that overexposure from the air in their parents basement is starting to affect them negatively. Just keep on what you're doing and know that many of us really appreciate it!
David O'Neill Never seen that one before, seams impossible with the amount of voids in the bearings. There should be a orifice in the crank shaft on the flywheel sideit sounds like it may be plugged or it has a plug in it instead of the orifice
Great vids! Thanks. I have a question, hopefully you can help. After my 325 QR-25 shuts off and unloads, air continuously leaks from the unloader tower? What might I do to solve this issue. Thanks again!
ladbak1 There are two ports on the tower a small one just under the diaphragm (untapped hole) the other port should be 1/8 NPT(pipe thread) in about the middle of the tower . If air is leaking out of the untapped port your problem is a leaking diaphragm if it's leaking out of the 1/8" port when off the problem is the HP discharge valve. The HP discharge valve acts like and is the discharge line check valve ( it's the only thing keeping the air in the tank when the unit shuts off)
I just bought a Quincy qr325 its missing parts but I can't find a good enough diagrams to know exactly whats missing. Do you know where I can find a good exploded view? My 325 is a little different then yours. There's a 4 in the box after the model 325.Thanks Bill
Hello came across these awesome videos while searching to do something similar myself...thank you for uploading your knowledge...i was wondering if your still doing stuff like this being that this was uploaded 8 years ago...on my birthday...lol...i have a Quincy QST 25 rotary screw compressor that runs all the time as it setup for cont auto...is there a way to make it run dual auto so that it shuts off after building up pressure instead of uploading then unloading...there is a switch that says "cont-auto-dual" and it runs on the cont side but does nothing when i turn the switch to dual??? my electric bill was over $1,000 the 1st month i used it...that's triple of my normal bill...i can't find anything online and the Quincy service people are horrible...any help or leads would be greatly appreciated...thank you Joe
Hey Joe thanks for the comment, I'm sorry to hear that your not having much luck with the local Quincy distributor, Atlas copco purchased Quincy a few years ago and everything has gone downhill since then. Quincy QST25 with dual control. Running in constant or otherwise known as continuous means just that it won't start and stop it will just load and unload as the motor continues to run. In the auto dual mode the compressor loads and unloads in the same manner The only difference is when the compressor fully unloads a timer starts running it's typically set for around 6 minutes If with in the time that the timer is set for if the compressors Pressure switch contacts do not close or in other terms if the compressor does not call for air pressure the compressor will shut off, Upon falling air pressure the contacts on the pressure switch close and the compressor restarts. Keep in mind that if the compressor starts and stops more than 6 times an hour it's better to run it continuously. It sounds like from what your describing you have defective unload timer, If you select auto dual and hit the start button and the unit will not start more than likely it's a defective unload timer. Good luck and thanks for subscribing!
@@rotarycomptech Thank you for replying and thank you for the advise...i will check the unload timer immediately...we got the compressor for $1,100 about 3 months ago and have had it up and running for about 2 months 5 days a week 8 hours a day...it has been running on cont auto and loading/unloading since we got it...i saw the timer inside the control box and wondered what it did...lol...as soon as i get this compressor setup on the auto dual mode i am going to rebuild another compressors piston and rings as it takes a long time to build up pressure...there was some oil in the tank recently and when we shut it off it spins a lot longer then it ever did...seems like it has no compression...then after that we have a nice Quincy air motor going on a big Kohler gas compressor that the air motor seized up and we bought it a few years ago for $100...busy busy busy the projects are never ending...thanks again for your help
Interstage pressure should be only 45 psi your problem is the HP inlet valve. Make sure the disc is not stuck open ..Worn valve bumper or pinched between the valve body and bumper or a obstruction, carbon rust ect..The sensor is the hydraulic unloader N/O closes W/ oil pressure so yes it is operating correctly. Also check to male sure the o-ring is still on the unloader plunger.
I have a 340 that's blowing oil in to head assembly not sure what would cause it to do that bad rings has new head on all new vavle assembly bore look good I'm guessing wore rings. Or could a vavle cause it to suck oil past rings just need some help
Your best bet is probably to remove the head and run it without the head on it and see if it is pumping oil past the rings. More than likely depending on the age, it probably needs honed and re-ringed
i have a twin unloader 325 , it dosen't load after starting, it starts venting through the hole in the side of the tower . if I crack the 1/4 in line it relieves pressure on the diaphragm then starts pumping . got any tips ?
@@rotarycomptech i called my local dealer there reply was " its probly post ww II ,send us a pic " do you have a good source that will deal with these oldies ?
Hi . tis video is super helpfull. since 2011 still poeple reply. i need your help. i have pictures of what i have. this thing is more then 70 years old i think. i don't know where to buy and what to renew.after the system gets to 50psi. i hear and feel more coming out and less geth in at the intake filter. i like to know how to repair thia item.what to look for.Quincy is good item and expensive i see.hmm.
Do you know much about speedaire,,,I know they was Smith and now taken over by American eagle,,,,I just bought a 1980 four cylinder compressor,,,I'm restoring,,,,she's a beast,,,
THE COMPRESSOR GURU IS A BIG FAT DUMB GOOF!!!!
What's wrong with The Compressor Guru
Often imitated on TH-cam but never duplicated. Still the best video series on the topic
Let me add my appreciation and thanks. This was as good as it gets.
Thanks Charles I appreciate your comment✌️
Hi. First off, I spent quite a while last night watching 7 or 8 of your Quincy 325 teardown and rebuild videos. For anybody interested in doing this, you have created an incredible resource. I am a little stunned in reading through your comments that this tjkslice character is razzing you all the time, and secondly, that years later you are still answering every question and trying to help everybody who posts comments. Every single person!!! I'm getting my first 325 now, it is an ROC 7 from 1957 or so, and I know I will have a lot of work to do on it, but I'm not sure I would have even wanted to take on the project at any price without having watched you explain exactly how they work and what is involved in restoring them to function properly. Thank you!
Hey, I just wanted to say THANK YOU for sharing your expertise in these videos. I've now rebuilt two Quincy compressors, a model 306 and a 240, using your approach. It would have been a hell of a lot more difficult without these tutorials.
Thanks for the nice comment Thom!
I am galad they helped you
Just wanted to say thanks for sharing your knowledge and nice presentation. It's not often you find a video from 2011 this well done and this useful. THANKS
They don't make um like they use to is a under statement. With that ole guy. She's now ready for another 50+ years of work. Terrific job rebuilding it. Not many people take the pains and care to do the job right as you do! Particularly impressed, with painting the inside of the case! Very Nice!!
Excellent series. I'm looking at buying my first two stage air compressor and trying to dig deeper for information. Wow, this was it! I appreciated the quality of work and knowledge you shared. Well done, and thank you for taking the time to document this rebuild so thoroughly.
Thanking you for a wonderful tutorial. I did auto mechanics diploma in my teens, learnt a lot about compressors with your tutorial.
Hey Dave !!!
Man you did one fantastic job Brother !!!
You have unleashed the Beast , for many more years of Service !!!
You are a man very attentive to every last detail !!!
Great job my Friend !!!
I'm off to get Mom out of rehab , take care Dave !!!
Hello Dave, Thank You for the great videos. I just rebuilt the head on my 325 roc 7, and the hp discharge valve still leaks, but I just realized that I didn't lap the seats before I installed the new valve disks. I'm going to do it today and reassemble. I really appreciate you sharing your expertise.
Really enjoyed your videos and I think they were the most informative I've had the chance to ever watch on youtube!. Really learned a Great Deal that will more than likely carry over into other compressor projects I do off and on. Real Class Act and easy to watch when you know the person your watching knows all the trick from experiance!!
Thanks for the videos!! I rebuilt my 325 watching these. One thing I didn't hear you didn't mention how much oil pressure you should run on a 325. Also I have the older vane style oil pump and notice that it takes 10 seconds or so to get oil pressure.
18 to 20 psig Is what Quincy recommends
I'm redoing a 325-16 and these have been very helpful. Thanks for the anti seize reminder. Scraping off the old gaskets was a pain. I immersed the head casting in Esprit rust remover and it made the inside clean up much easier. Dave
Watching your video 9 years later I am planning on a head job on a Kellogg 331 TV I just acquired I will be vapor honing the head
I'm assembling mine tomorrow. ROC 13 Valuable videos. Thank you
Now you really have my attention. Your video is great and now I firmly believe you are going to save me some money too. I did as instructed. Plugged it in, let it pump up to about 60psi, pulled the plug and in about 2 seconds I got the pfffffft sound and then the air started coming out of the tower bleed hole.
If this were a school project you would get an A+. Made me want a machine like this. Wish parts were more available.
Fixed both valves and now it runs, sounds, acts and pumps like a new compressor. When I put my fingers over the inlet it runs almost silent and the oil pump stops reading pressure on the gauge. I can still feel a little air escaping out of the bleed hole on the tower after it shut off. Maybe the discs will wear in. Pumped to 160 before I unplugged it and did it pretty fast. Interstage operating right at 30psi now.
Dave, thanks for all your help! I feel like I have a new compressor again.
Great video series on Quincy rebuilding. I have a couple Quincy 370's that need rebuilding and this video will help a lot. Also really like the video on the dual control installation, as I am planning to run one off of gas engine.
Those are really efficient - looking valves, quite an impressive compressor!
Appreciate your time in making the video.I still have 6 of these on campus (actually duplex style, so 12?), out of a total of 41 compressors total, and your video helped me in the task of working on rebuilding the valve components.Most of the Quincy units ,I have, are about 30 years old.
This has got to be the best sounding compressor I've ever heard. Thanks for the great videos. If I ever find one I'll get back to them for inspiration :-)
Thanks for the vid, I purchased a good used QR-25 from a screen print shop, all the paint is burned off the output valve and discharge line. It works great, nice spin on oil filter, found a napa cross over. My unloader unloads twice though, one short spit then a longer one with a quarter second pause in the middle.
Great series! Watching you let me know how little I know about restoration;-) I don't have anything like that, but it was cool to see it done rite.....
Great video tutorial series! Nice to see quality craftsmanship.
Dave, first of all thankyou to the nth degree for doing this series. Quincy is very tight with allowing quality service manuals to be published or shared. You have saved me and thousands of others, THANK YOU sir!!!!
I just purchased a 325 ROC 12 and mine has the 2 unloader valves. It also has a middle area that I havent seen on any others. It is between the pump and the motor and it has a pipe coming off the compressor head and then a square set of cooling fins and then a larger pump type looking contraption that enters into the top middle of the tank.....Do you have any clue what that could be and what it does? I am just starting to gut the compressor and start the cleaning process.
If you do not have time to answer, I more than understand. YOU ARE DA MAN!!!!!!!
Thanks again for all your time and courteous help
Thanks for all the nice words Jim!
That contraption you're referring to is what Quincy compressor named a cushion chamber, It's designed to take out the pulsation of the compressed air In hopes of making the whole compressor package quieter, A lot of the noise generated in a reciprocating compressor is through the discharge line, That pulsating compressed air entering the tank causes what's known as intank noise. The cushion chamber actually did work but there was one inherited flaw, They had a tendency to become log with oil and carbon, In some cases it would restrict the small tube that feeds the tank, There's also a relief valve located on the cushion chamber that had a tendency not to open or also become plug with carbon, I think you might know where I'm going with all this, What's your say a few of these cushion chambers exploded and therefore Quincy way back in the day discontinued to use of them, I would strongly suggest you just get rid of the thing and plum the discharge line straight into the tank hopefully there will be an opening somewhere that you can use.
Good luck in the future!
@@rotarycomptech Thank you so much for replying, especially so quickly!!! Can I totally remove it from the tank and run plumb the discharge directly into the remaining hole, or is it too large?
@@jimtrimble3040 As long as the whole opening isn't smaller than the discharge diameter which I believe is 3/4 inch or 1" some around their,
@@rotarycomptech Since I will be using this compressor no more that 5 hours a week, Can I just focus on keeping that chamber cleaned out or would that still be too much of a
risk? If so, Could I connect the discharge tube into one of the threaded end plugs? I have one at each end of the tank about 1/2 way up from the bottom. Sorry for the quantity of questions
@@jimtrimble3040 Either way will work, The cushion chamber was just found to be unsafe
I had a quick question, during the assembly, you mentioned and clearly demonstrated the discharge valve springs are painted white. According to the parts list, there is only one valve spring (Quincy part #7270) available for both intake and discharge valves. I recently purchased this valve spring and found it had no kind of paint or distinguishing markings.Is there a noticeable difference in size, shape, and or gauge between your white and unpainted springs is it safe to interchange part #7270?
I have a Quincy 320 - trying to setup for a friend but it has issues. It knocks a bit on startup (no air pressure) but stops once there is some pressure in the tank. Then when it gets to about 60 PSI, air starts coming out of the unloader valve. I've cleaned up the valves as best I can, new diaghram on the unloader but don't have the tools to go further. Thoughts? I have a Service Shop about 1.5 hour away.
I took the hydraulic un-loader line off of the tower and the bleed stopped leaking air. Put my finger over the copper line from the un-loader and it built up pressure. So I'm guessing the problem is the small valve at 12 o'clock on the oil pump that is fed by the copper line from the air tank and line going to un-loader tower?
Thanks again, the o-ring is still on the brass plunger and it's in good shape. After I put it all back together but before placing the rubber diaphragm in place I pressed down on the assembly with my finger and it felt sticky. It wasn't free like I think it should be. I'll take it apart again and see what I can see.
If let it pump just for a minute it gets up to 40psi or so and the pop off valve in the head starts leaking and drains the tank. Will a new PRV resolve this or is it indicative of something else going bad, i.e. diaphragm?
Should I buy a head rebuild kit online and a new PRV and do what you did in this video? Will I need the spanner wrench and huge hex for the diaphragm tower?
Switched places with the tank pressure gauge and PRV. Interstage pressure appeared to register equal to tank pressure up to 100psi when the PRV popped and I unplugged the motor. Still getting pressure on the unloader line coming from the sensor on the oil pump when not running. Is that normal? No air escaping out of the intake filter inlet. That's a good thing!
I'm getting deeper into it and need more help. Earlier I said air was coming out of the PRV, it's not, it's coming from the bleed hole in the unloader tower. I pulled the diaphragm and it is not cracked or leaking. Visited my Quincy dealer. He wants $180 for a Head Overhaul Kit which includes gaskets, two different sets of springs, pins and springs, discs, and an oil pressure gauge. $13 for an oil filter. That seems high. Are the kits available on the internet reliable?
Just bought one of these QR-25 (325) compressors. Actually it is the second one. My dad had an old one but it has two diaphram towers on it. This one only has one. What's the difference?
This newest one is a 1990's vintage. It needs some help and so do I. When I plug it in and and it starts pumping it seems slower to build pressure than it did when my company bought it new 23 years ago. Could the valves be causing this?
Great videos, I love the QR-25s. Work on a little myself.....but nothing this extensive yet. Thanks for some great info!
Okay, bought a head overhaul kit which is just gaskets, copper valve seats, diaphragm, valve discs and springs. When I took the valve covers off I noticed rust on all but the big cylinder intake side. One discharge valve is loose. The shoulder bolt will not tighten enough to draw up the bottom of the valve to the top. Maybe that is part of my problem?
I have all the parts soaking in Evapo-Rust. Hope to assemble tomorrow.
Can I put a washer under that shoulder bolt so it draws up tight?
I think your problem is the HP discharge valve when shut down does air escape from the inlet filter? does your machine have a interstage relief valve?...Can you shot a video of the compressor and it's related problems? It may be helpfull...Thanks Dave
I recently acquired a "Quincy 325-15" that appears to be in "like new " condition ( reportedly used in HVAC process control). Recently, it started blowing high pressure air out through the hole in the head unloader after establishing normal oil pressure during operation. I have not dissect the problem yet. Can this be a simple case of a torn diaphragm? Thanks for your time.......
It's clear to see why Quincy is ahead of the rest with the valves instead of Reids,,,are they still useing valves in there new compressors?
Excellent job Mate!!!!
Hi Dave, great vid series! You did a wonderful job documenting the rebuild process and diligently responded to commenters to provide additional info. Thanks! My question: Do you know the earliest 325 ROC number Quincy still supports with available replacement parts? Thanks in advance for your response!
your videos on this are Awesome.
I picked up a 325-13, I just ran it for the first time, and when it shuts off it dumps all the tank air out of the un-loader port, if I unhook the un-loader tube there is a small amount of air coming out of it.
It sounds like the high pressure discharge valve is stuck open
+ROTARYCOMPTECH
Thank you' I will open it up and take a look, so a small amount of air will always come out of the hyd un-loader valve? who do you recommend for parts?
IBRACIN get your parts through a local Quincy distributor, the only time air will leak out of the hydraulic unloader is when there is an absence of oil pressure
+ROTARYCOMPTECH
so I took apart the high pressure discharge valve , it was really gunked up, cleaned and reassembled, and that did fix the tank dumping at at very high rate.
but it still leaks air from the hyd. unloader after it shuts off, to be clear I know its supposed to dump the head pressure after oil pressure goes away, and it does do that, but then it continues to slowly leak air... it looks like the sealing ring on the brass plunger is just really hard, is that a serviceable part, or do i have to buy a whole new unloader.?
Thank you for your help.
+IBRACIN
I REBUILT the valves, installed new kick off springs, and a new unloader piston, rebuilt the hyd. unloader... all is well except, after it cycles off it leaks air from the crankcase, its very small but still a leak. just wondering where to look to fix it?
Great job! It looks like a compleatly different compressor.
I am considering buying a 80 gal 325-7 compressor. It was built in 1958. I saw a complete overhaul kit on ebay for $418
Is this a good way to go?
PART: MOK 325-6-Q
Quincy style overhaul kits have been assembled to include gasket kit, shims, piston pins (lock rings if used), piston ring kit, piston pin bushings, insert bearings (if used in original rods), main bearings, valve discs, springs, o-rings, oil seal and unloader diaphragms if required, to recondition one compressor.
does it need regular 10w40 oil? same as in the car. Infact the piston is almost the same as in a car
Nice job, I had a quincy 325 and I traded a friend for a welding machine, he needs an electric motor, and I was wondering what motor you have on this compressor. thanks.
I can't win for losing. I had to replace the motor capacitors which is why the Mag starter burned up. Now I have done the head overhaul and the pop-off on the discharge side is popping off with each stroke at about 100 psi. I used a silcone spray to protect the cast iron valves. I wonder if it is sticking the disc to the valve?
I noticed a slight nick on one of the discharge valves seat. I purposely put it on the big cylinder. What next? I will have a mint in this thing if I keep going.
thx
and for the dismantling the unloader their are many types of unloader i'm asking about the one installed on the oil pump direct can you help me with this
Find out what the interstage pressure is when running should be around 45 psig also does the relief valve lift when off and W/ 100 psig in the tank? Iam trying to find out if it's a HP discharge or suction valve problem don't worry will get it right!
what does a rebuild kit like this cost? i found a similar quincy pump that may need one. Also any idea what the cfm is on a pump like this is?
I just picked up a 70s 325. It accumulates water in the crankcase oil very quickly, I have to wipe it out with towels by pulling side plate. I had about 3/4” of white sludge in the bottom over a 3 month period. It runs maybe 3 to 4 times a day. Can you point me in a good direction. Also thank you so much for these videos.
Simply put your not running your air compressor enough and your ambient humidity is being collected in the crank case. It’s a common problem for people like yourself and me who only use their air compressor for short periods of time or not long enough to get the oil in the crank case up to temperature, after all this is what causes the moisture to flash off of the lubricant. You may try to install a crank case heater but in most cases it doesn’t work very effectively.
If you don’t care about power cost and the compressor running you can always install a timer drain solenoid valve to drain the condensate from the tank and have it set to go off every couple of minutes for 20 seconds or so. In any case just like me you have to get in the habit of running the compressor up to temperature before you shut it down for a while
@@rotarycomptech really appreciate you answering my question especially on an old video! I was afraid that was the case. I’ll just keep an eye on it and change the oil once a month if need be.
My tank leaks down over night so I drain it completely every day but it only takes 10 min to fill to 190 psi so it barely gets warm.
I find it simply amazing how many people you have helped, or given the "idea" to rebuild an old piece of history.
I myself saw one of your videos and made it a point to go hunting for one.
Night and day difference between the compressor that I had been using for the past 12 years.
I found a 325-13 that ran great... however had been sitting for quite sometime.
I tore it down to noting and pretty much followed your videos to the T.
I am having one slight issue that I know you have addressed on here...
The HP unloader tower leaks at the 1/8 npt hole. You have said that it is an issue with the valve assembly... however I am curious... how exactly? When I did my valves i started with 500 grit and worked up to 1200... extremely smooth with no imperfections at all. I really don't want to tear up the paint job... and know I could just add a check valve to resolve the issue... but I'm just curious what exactly would need done to fix this issue?
The only thing I didn't replace that I probably should have was the brass plungers.... but from what i gather... that isn't my issue and I am just paranoid for no reason.
A side note... has anyone told you that you sound JUST like Nicolas Cage?
John F Thanks for the comment does it leak when running or off or both?
It is only when it is off.
I honestly had no idea it was leaking until it kicked on in the middle of the night.
I sprayed down the very few fittings from the tank and found nothing... then I remembered seeing a video somewhere about one that had air leaking from the air filter (tower was plumbed to the top head port) obviously had a large leak.
Thanks for all of the support you have given everyone.
John F Than it's the HP discharge valve, if it's just slight It may just need some run time to seat the disc and seat
Nicely done. Great Video series.
Thank you sir!
can you give me advice on this. I just picked up a 325 ROC 104. Looks brand new but it seems the ropes that moved it dropped it and bent the crank pretty good. wobbles bad. can a machine shop straighten it. New crank is really pricey. Also there's an older Champion nearby that looks clean. Is the 325 a much better pump. I'm up for the work if its a better machine. Really a shame. Thing looked perfect.
I would check the interstage pressure when running should be around 45 PSIG and the relief valve should set for 90 #...If it lifts when running it's typically the HP inlet valve if it lifts after shut down it's the HP discharge valve in any rate it's a problem on the HP side.. A pipe wrench will work to remove the tower the hold down can be removed easier when removed if you don't have the tool
@oocheewalley I am not up to date on what record of change number determines the obsolete pumps, Does your pump look like mine does the head have round valve covers opposed to plates? does it have a oil pump? is the on loader on the side or on the front a k a 3 way valve or hydraulic unloader if none of this makes sense shoot a video of the compressor I will be more than happy to help you
Hey Thanks for the videos. How did you get the inside of your compressor painted red? Is it powder coat or paint?
Thanks again
Its automotive primer
@@rotarycomptech great thanks. Any recommended special prep other than just cleaning and getting it oil free.
Hey Jim,
Sounds to me like your crankcase breather isn't working properly. There should be a 5/16 OD copper tube that runs from the crankcase opposit side of the hand whole cover To the intake portion of the head. From what you're describing it sounds like it's not venting. You can remove the line at the crank case to see if its operating some models had a tube that mount inside of the crankcase and inside of that tube was a plastic ball kind, It acts like pcv valve in a automobile. The motor stalling issue sounds more like a problem with the motor or the incoming voltage rather than the compressor but to confirm or deny there is an issue with pressure you may want to install a pressure gauge on the discharge line before it enters the tank to ensure you're not over pressurizing the compressor if you know what I mean there could be a restriction in the discharge line I think I remember you telling me this unit had the old style cushion chamber on it?
Also if you have and amp meter check the amperage when the motor starts to bog down and also check the voltage it should not drop off by more than 2 or 3 Volts at the most.
Good luck!!
Loved the serie. I'd like to see a rebuild video on a devilbiss/devair 447 as I just bought one. Guess I'll make a video series if I dont find any
Where do you buy your parts? Great videos BTW, I've learned a lot from them. Thanks!
I believe that that record of change is mostly obsolete.. does it have round valve covers on one side of the head?
ROTARYCOMPTECH, I have a new QR-25(325) and I just rebuilt the head watching your video(Thanks!). Compressor starts at 135#'s and stops at 180#'s, the run interval is right at 3min, how do I extend the run time? There is moisture rusting the valves.
when did quincy go to oil filters on 325
Are you talking about the hydraulic unloader that is threded 1/4 NPT...
The new style?
I believe the discharge spring has a bit more tension than the suction.. But Iam not 100 percent on that. Quincy has a TH-cam channel they might answer that question for you, but thanks for asking
Is it absolutely necessary to prime the crankcase? Rebuilding a 210 unit and lost most of the original primer while cleaning it. Crank wasn't rusty at all. Is it to seal in the oil or to prevent rust?
Some of the old crank cases were primed due to porus castings leaks in the casting itself
@@rotarycomptech thanks for the reply. This whole series has been very helpful. I think I will take the chance of not priming it. Already tried some enamel but I didn't like how it was curing in there (didn't get all the oil out) so I stripped it clean again. For reference, what was the primer that you used?
@@bcouri1 it wasn't Automotive lacquer based primer
Hey man thanks for posting the videos. I have just recently acquired a 325 ROC 12. I tried calling the only Quincy distributor in my state to get pricing on parts and the support tech said that "That compressor is no more than a boat anchor. I would be more than happy to set you with a new one." No thanks
Can you tell me where you purchased your parts from, I would to get some reliable help?
Thanks again
Good video. I am working on a project that perhaps you can help me on with some advise. I'm a HVAC heavy tonnage mechanic in the trade for 35 years. Been working on some high pressure refrigerant recovery units that can transfer around 1,000 to 2,000 pounds of R22 or R134a in a recovery tank. Been thinking about trying a quincy model 210 air compressor. What are your thoughts? Thanks
I saw you comment on another video on a 325 roc 7 that it is an obsolete model and parts are not available. is the ROC 7 different than this model? Thank you
I don't have any information on the year versus record of change ,
But the difference was typically The oil pump and valve assemblies
Nice use on the glass lapping
@swasey1952 The tool is made by Snap-on the P/N is N6664 I don't know if it's a Quincy or a Snap-on P/N it maybe eather or? You might try to heating the the valve cover and try turning the hold down screw clock wise with a piece of angle iron
Very well put together and informative rebuild series. I am happy with the unique tips and tricks you've shared. I purchased a Quincy 5120 a couple of days ago. Upon first inspection I spun the flywheel to make sure it wasn't locked up. I noticed that only one head was giving a deep chug from the intake filter as I was turning it over by hand. Shouldn't both sides have a chug? It is an LS and I am wondering if the valves position of the dual control may affect what noise I heard from the one head.
dapaid1 Thanks for the comment,
yes both cylinder Banks should have the same audible sound.
If not more than likely the compressor has a stuck unloader piston or plunger causing the inlet valve to be open.
Or worst case scenario it has a couple of broken connecting rods.
I think I've rebuilt more of the 5120 model Quincy compressor than any of the other ones.
In an odd way I miss those old days
Thank you. I will start posting videos of it as soon as I get it home. It is an era 1974 and I am thinking it may actually be a 5105.
dapaid1 the only difference between the 5105 and the 5120 is the crankshaft and the cylinders
the only really way to tell without taking it apart is the the length of the cylinder
From what points do I take the measurement and what dimensions am I looking for? The inspection plate was replaced, as you will see when I post the video. I understand the roc may be stamped on the crank. Will it be visible if I open up the inspection plate cover?
dapaid1 the part number on the crankshaft will be different but I'm not so sure that you could see it from the inspection plate.
on the cylinder itself where the bolt-holes fasten it to the crankcase on the 5120 model it's pretty beefy about 1 inch in diameter.
on the 5105 it's about half the size or roughly a half an inch.
I can't tell you the exact dimensions as I don't recall them and I don't know that they're published,
it was just a visual familiarity with the two pumps sitting side by side.
@fastst1 the hydraulic unloader on your air compressor should be different then mine if your pump has the oil filter the hydraulic un loader should thread into the side of the oil pump housing a quarter inch line should run up to the on loader tower I would suggest you install a pressure gauge in that quarter inch line but don't remove it from the tower stop and start see if the pressure fluctuates
do you still remember any specs on this , I have one from 1975, motor ( electric) went bad, had some ppl mess with it who should not have and .... now I need to know clockwise or counter clock wish and the RPM I likes so I can replace the motor .. I through a cheap 2hp 1800 rpm one on there to make sure it still works, and it will build pressure both directions , but with the pully having "fan blades " on it im sure it ment to go a certain way .... thanks
There should be a directional arrow on the fly wheel itself. The older compressors with the old vane type oil pump will make oil pressure in either clockwise or counter clockwise rotation
I dont know but i dont have the part that u dismantled that have D side and R side my unloader tower is connected to a part attached to the oil pump and i need to dismantle
Your videos are great and really helped me rebuild my 325. Many thanks. Mine is running great but doesn't unload after stopping. When the oil pressure drops from 20 to zero I don't hear any hiss of air to unload the head. Also there is no air coming out of the (upper) port on the hyd. unloader when the unit is running, thus no air to the diaphragms, but the unit pumps air anyway....don't know how this could be. Any suggestions? Again, thanks for sharing your knowledge and expertise with so many watchers.....JF
it sounds like you have a bad hydraulic unloader when the compressor is running and has developed oil pressure the hydraulic unloader should close and remove the signal to the unloader tower diaphragm. you need an air signal to the diaphragms to unload the compressor not to load it up
thanks for the comment !
ROTARYCOMPTECH Thanks, Dave, I can see that the hydraulic unloader piston sticks and doesn't open and close easily. Is it any big deal to rebuild this unit? does it just come apart after driving out the roll pin? Thanks again, and keep those Quincys chugging. JF
Joel Fisher Your better off replacing it
Where is the best place to buy new valve components for rebuilding my top end of my 325?
At this point, I don’t think it really matters much after Atlas Copco bought the company. I think most of the parts come from China.
@turboslag Thanks for your nice comments! I think it would be easier to get the Quincy pump over there to get
a Skyline over hear
hey paul first thing try removing the quarter inch line that goes to the unloader tower when the compressor is running and has oil pressure there should not be a air signal second check to see if the unloader plunger still has the o ring on it also check to see if the piston underneath the diaphragm isn't rusted and stuck down if that's not it then the high pressure intake valve is stuck open it's not uncommon to see rust in the high pressure area causing parts to stick together
Good night, I have a Quincy 325 compressor, after filling and disarming it is losing air, through the air filter outlet, what can it be?
A leaking HP discharge valve
This videos are very helpful and I have almost completed rebuilding my 325. I have a question though. Would it be a bad idea to rotate the I high pressure side valves to the low pressure side and vice versa?
PracticalTactical typically the valves on the low pressure side are in better shape than the high-pressure ones and it's a good swap to go that direction
especially for the discharge valves
Yes sir I figured that wouldn't be a bad idea. I really want to thank you for the time and effort you put toward putting these videos up and answering people's comments and everything. You have really been a great help and a good person!
PracticalTactical Thanks for the nice comment!!!!!!
sometimes they seem a little hard to come by these days
what is the snapon tool number for the tool to remove the ring in the hed the unloader screws on to
sir
what is the different between discharge valve spring and suction one
The dual unloader towers are for continuous run operation. If it's slow to recover it's the valves.
Nice video, great commentary!
I now think of you as Mr. 4th Amendment (anti-seizure).
Hey Chad to my knowledge Quincy doesn't offer a rebuild kit only individual
parts at one time they had a head kit to rebuild the valves but i don't think they offer that any more it was called a VIP kit. The ACFM rating is around 18 SCFM. Good luck thanks for the comment
@grizzly303 Thanks for your comment I am glad it helped you the Binks compressor is the sam as the Quincy just private labled
Thank you for making and uploading these informative videos. They were a big help in helping me rebuild my personal 325-13. I have a question for you. My rebuild turned out really well except for one thing, it will not unload. I disassembled and double checked the unloader tower and the brass unloader valve in the block and both seem to be fine except not only will it not unload, The oil pressure will not return to zero when the compressor is turned off. It hovers around seven psi. Any thoughts you might have what could be causing this and what I should look at next would be greatly appreciated.
Best regards, Dave
PS it always amazes me that no matter how good somebody tries to do by posting videos to help people they still attract trolls who have nothing better to do than to criticize them. I'm not sure if they do it because they're in that dire need of attention or that overexposure from the air in their parents basement is starting to affect them negatively. Just keep on what you're doing and know that many of us really appreciate it!
David O'Neill Never seen that one before, seams impossible with the amount of voids in the bearings. There should be a orifice in the crank shaft on the flywheel sideit sounds like it may be plugged or it has a plug in it instead of the orifice
I found a 7.5 HP on a 80 gal tank for $550 in Hatfeild PA is this the one?
Great vids! Thanks. I have a question, hopefully you can help. After my 325 QR-25 shuts off and unloads, air continuously leaks from the unloader tower? What might I do to solve this issue. Thanks again!
ladbak1 There are two ports on the tower a small one just under the diaphragm (untapped hole) the other port should be 1/8 NPT(pipe thread) in about the middle of the tower . If air is leaking out of the untapped port your problem is a leaking diaphragm if it's leaking out of the 1/8" port when off the problem is the HP discharge valve. The HP discharge valve acts like and is the discharge line check valve ( it's the only thing keeping the air in the tank when the unit shuts off)
ROTARYCOMPTECH what is the Alan screw invader the gages
I just bought a Quincy qr325 its missing parts but I can't find a good enough diagrams to know exactly whats missing. Do you know where I can find a good exploded view? My 325 is a little different then yours. There's a 4 in the box after the model 325.Thanks Bill
Rail guy I would just Google search a manual online
Hello came across these awesome videos while searching to do something similar myself...thank you for uploading your knowledge...i was wondering if your still doing stuff like this being that this was uploaded 8 years ago...on my birthday...lol...i have a Quincy QST 25 rotary screw compressor that runs all the time as it setup for cont auto...is there a way to make it run dual auto so that it shuts off after building up pressure instead of uploading then unloading...there is a switch that says "cont-auto-dual" and it runs on the cont side but does nothing when i turn the switch to dual??? my electric bill was over $1,000 the 1st month i used it...that's triple of my normal bill...i can't find anything online and the Quincy service people are horrible...any help or leads would be greatly appreciated...thank you Joe
Hey Joe thanks for the comment, I'm sorry to hear that your not having much luck with the local Quincy distributor, Atlas copco purchased Quincy a few years ago and everything has gone downhill since then. Quincy QST25 with dual control. Running in constant or otherwise known as continuous means just that it won't start and stop it will just load and unload as the motor continues to run. In the auto dual mode the compressor loads and unloads in the same manner The only difference is when the compressor fully unloads a timer starts running it's typically set for around 6 minutes If with in the time that the timer is set for if the compressors Pressure switch contacts do not close or in other terms if the compressor does not call for air pressure the compressor will shut off, Upon falling air pressure the contacts on the pressure switch close and the compressor restarts. Keep in mind that if the compressor starts and stops more than 6 times an hour it's better to run it continuously. It sounds like from what your describing you have defective unload timer, If you select auto dual and hit the start button and the unit will not start more than likely it's a defective unload timer.
Good luck and thanks for subscribing!
@@rotarycomptech Thank you for replying and thank you for the advise...i will check the unload timer immediately...we got the compressor for $1,100 about 3 months ago and have had it up and running for about 2 months 5 days a week 8 hours a day...it has been running on cont auto and loading/unloading since we got it...i saw the timer inside the control box and wondered what it did...lol...as soon as i get this compressor setup on the auto dual mode i am going to rebuild another compressors piston and rings as it takes a long time to build up pressure...there was some oil in the tank recently and when we shut it off it spins a lot longer then it ever did...seems like it has no compression...then after that we have a nice Quincy air motor going on a big Kohler gas compressor that the air motor seized up and we bought it a few years ago for $100...busy busy busy the projects are never ending...thanks again for your help
Interstage pressure should be only 45 psi your problem is the HP inlet valve. Make sure the disc is not stuck open ..Worn valve bumper or pinched between the valve body and bumper or a obstruction, carbon rust ect..The sensor is the hydraulic unloader N/O closes W/ oil pressure so yes it is operating correctly. Also check to male sure the o-ring is still on the unloader plunger.
@oocheewalley Thanks for the nice comment. Whare do you live?
I have a 340 that's blowing oil in to head assembly not sure what would cause it to do that bad rings has new head on all new vavle assembly bore look good I'm guessing wore rings. Or could a vavle cause it to suck oil past rings just need some help
Your best bet is probably to remove the head and run it without the head on it and see if it is pumping oil past the rings. More than likely depending on the age, it probably needs honed and re-ringed
What is the difference between the Quincy Comps and the Binks Comps with the similar designations such us Binks model 33-576 Serial 325-10?
Thanks.
There both the same pump Quincy private labeled the QR-25 series for Binks
i have a twin unloader 325 , it dosen't load after starting, it starts venting through the hole in the side of the tower . if I crack the 1/4 in line it relieves pressure on the diaphragm then starts pumping . got any tips ?
Replace the hydraulic unloader
@@rotarycomptech i called my local dealer there reply was " its probly post ww II ,send us a pic " do you have a good source that will deal with these oldies ?
i removed the unloader to take pics. the o rings are hard and have a few small groves in the inner one .can i just replace the o rings ?
@@gaildavis3433 nope your kinda shit outta luck
Hi . tis video is super helpfull. since 2011 still poeple reply. i need your help. i have pictures of what i have. this thing is more then 70 years old i think. i don't know where to buy and what to renew.after the system gets to 50psi. i hear and feel more coming out and less geth in at the intake filter. i like to know how to repair thia item.what to look for.Quincy is good item and expensive i see.hmm.
Do you know much about speedaire,,,I know they was Smith and now taken over by American eagle,,,,I just bought a 1980 four cylinder compressor,,,I'm restoring,,,,she's a beast,,,