[Joelk]

I just bought a VERY old 2 stage compressor that was taken out of a Service Station when in closed a couple years ago. It has a very heavy 80 Gallon tank that was made in 1957 and a Quincy 325 (4) pump. Not sure if the pump is original, but it has matching paint so I assume it may be. I may not use the old tank, will Hydro Test if before deciding, but I do want to restore the pump.

I have started tearing the pump down and it looks like it is in great condition, especially for it's age. I pulled the head off and there is very little wear in the cylinders. No ridge at the top of the cylinder at all. Had some carbon/varnish on it, but I scrubbed it with a scotchbrite pad and can no longer tell where the rings stopped. Big pison is stamped Std so assume it is original. Can still see cross hatch on the walls. Some very light verticle scratches on the cylinder walls, but they are very light, similar to the crosshatch scratches.

I pulled the "valve covers" off of the low pressure side and found no broken parts or signs of damage, but unfortunately I had a mishap during the disassembly. On the top of the low pressure valve covers there are some things that appear to be nuts with cone shaped tops. I broke one of these off. I hardly put any pressure on it at all before it snapped off. It was the first one I tried and I did not try any of the others after it broke. Any suggestions on how to remove these without breaking more off? Any idea where I can buy a replacement "nut" and the "stud" it goes on?

After the mishap on the low pressure side, I have not yet pulled the "valve covers" off of the high pressure side as I did not want to damage anything in the process. Any tips on disassembling the high pressure side of the head?

I plan to contact Quincy and see if they can send me a Part/Svc. Manual, but any guidelines/tips/suggestions would be appreciated.

I have found a "Tuneup kit to Rebuild One Quincy Air Compressor Model 325 ROC 1 to 5" which includes these parts: Contains replacement parts for rebuilding one Qunicy Model 325 Compressor. This contains valve parts, piston rings, gaskets set, rod inserts, oil seal, unloader diaphragm and orings $89.00

And Head Overhaul to Rebuild One Quincy Air Compressor Model 325 wiith these parts: Head Overhaul Kit includes the Valve Disc, Springs, Valve Gaskets, Head Gasket, Valve Cover Gaskets and Unloader Diaphragms for rebuild one Quincy 325. $38.00

I'm not sure which one I should get. IMO (but I have no experience with compressor pumps) the pistons/ring are in excellent condition and assume the crank/bearings are in very good condition also.

I'm not really concerned about the additional cost, but sometimes if it ain't broke don't fix it applies. Suggestions?

Any tips on the rebuilding process?

Thanks, Joel

[oldred]

Those old pumps are definitely worth rebuilding and from what you have described about the cylinders I would think you should probably just leave those alone, they will take a tremendous amount of use before wearing out if they have been maintained properly. Check the bottom end for wear also make sure the crank/bearings are not loose or scored and there is no excessive end play, some end play is normal and is of no concern it is not as critical as rebuilding an engine. The heads/valves are almost always the main culprits when performance starts to fail under normal service but as you seem to be discovering these are also usually the hardest parts to deal with on these two stage compressors. There are a lot of parts you will have to deal with, a lot of small parts and as you also have found things can be damaged easily so I would recommend getting at least a parts diagram before going any further with the head disassembly. Once you can see how everything goes together it won't be hard at all but you want to be sure and work over a clean area where where small parts can be easily found if dropped! I would recommend starting with that head/valve kit because it sounds like the cylinders will be good as is and a good top over-haul should get you up and running

[Joelk]

Thanks for the reply.

Quincy e-mailed me some docs and I was surprised, and somewhat disappointed, to discover that my model apparently does not have a pressurized oiling system.

According to what they sent me, the ROC 6 was the first model that had pressurized oiling. I thought this was one of the most appealing features of the Quincy 325 and had just assumed that they all had it. Although I thought it was a great feature, I suppose it must not be essential as the pump I have is > 50 years old (Quincy said ROC 4 started in 1954) and appears to still be in excellent condition.

I'll check the crank, rods etc. and if all appears good I will proceed with the rebuild.

[oldred]

You sure do have an old one but don't worry it is no problem. Pressurized oiling is only necessary if that is the way the pump was designed and splash oiling is just fine, the only major advantage I can see with the pressure system is for operation in cold weather. Remember this is not an internal combustion engine you are dealing with even if it is similar and it is not subjected to the same loads or heat as the engine, also it runs at a constant RPM within a narrow RPM design limit so splash oiling can supply all the lubrication that is necessary. Did they send you a parts diagram? Use genuine Quincy parts and take care to do this right and you will be stuck with that thing for another 50 years!

[Joelk]

I did a bit more disassembly today. Pulled the crank inspection cover and pulled the rod cap off of the High Pressure rod. Bearing and rod journal look great. I may not even pull the Low Pressure rod cap as I have no reason to suspect it has any issues.

The rod cap has locking nuts on it. OK to re-use these? Any idea what to torque them to?

I took the rest of the "Acorn Nuts off of the Low Pressure valve covers. I feel certain that the one I snapped off before was previously damaged as I did not turn it nearly as hard as the others and they did not snap off. 6 of them came off fine and the other one had the very top (can see hole to allen key section)snap off inside the nut. I think I will be able to remove the piece from the nut and if so, I will just need to replace the stud. Will need a stud and perhaps a nut for the one that snapped off earlier. Any idea where to get replacement studs and/or Acorn Nuts.

I have drained the oil out and there was a fair amount of sludge in bottom of crankcase.

Suggestions on what oil to use. I have used Amsoil in the past, but it has been quite a while and an entirely different type of compressor. Would Amsoil be a good choice for this compressor?

[oldred]

Originally Posted by Joelk

The rod cap has locking nuts on it. OK to re-use these? Any idea what to torque them to?

No, you should replace them with the same type, do not use the common soft Ny-loc nuts. What size are the rod cap nuts?

[Joelk]

The rod bolts are 3/8" fine thread.

Any idea where I can get replacements of the correct type?

Any idea what to torque them to?

The ones that are on it appear to be Ny-Locs and still seemed to be working very well. They required significant force to turn, all the way off.

Another thing I found interesting was the "center crank journal" (approx. 2" in diameter, and 3/8" wide) that has a large 7-8" diameter "plastic ring" on it. It appears that part of the ring hangs down in the oil and I assume it acts to "throw oil" around inside the crankcase. I have never seen anything like it before and if someone had told me it would last 50 years with near (if not) daily use, I would not have believed it, but I assume it is original as there is no indication the crank has ever been out of the crankcase, and it would have to be removed to replace the ring. It appears to be in good condition so I guess I will leave it alone.

Are replacement plastic rings available?

[oldschoolrods]

Where in PA are you?? If you happen to be in central PA area I know a couple places you could get the nuts local, otherwise try Mcmaster Carr http://www.mcmaster.com/#

[Old Fool]

[QUOTE=Joelk]The rod bolts are 3/8" fine thread.

Any idea where I can get replacements of the correct type?

Any idea what to torque them to?

The ones that are on it appear to be Ny-Locs and still seemed to be working very well. They required significant force to turn, all the way off.

Another thing I found interesting was the "center crank journal" (approx. 2" in diameter, and 3/8" wide) that has a large 7-8" diameter "plastic ring" on it. It appears that part of the ring hangs down in the oil and I assume it acts to "throw oil" around inside the crankcase. I have never seen anything like it before and if someone had told me it would last 50 years with near (if not) daily use, I would not have believed it, but I assume it is original as there is no indication the crank has ever been out of the crankcase, and it would have to be removed to replace the ring. It appears to be in good condition so I guess I will leave it alone.



The slinger ring is a common item on plain and babbit type bearings in large hp industrial motors. ( 500-2000hp dc powered) They normally use a brass slinger that is split in half and fastens together with 4 brass screws, 2 at each lap joint. they run 24/7 for 10+ years with no maintence other than keeping the oil level attended to and oil changes.
Old Skool technology that works awesome for lower bearing speeds.

[Joelk]

I am in Bedford PA. Not a metro area. About 100 miles West of Harrisburg on the Turnpike.

I think I now have disassembled everything on the pump that I plan to take apart. Except for a bunch of carbon on things, and the "valve cover stud" (and the valve cover it is stuck in) that snapped off when I tried to remove it, everything seems to be in good condition.

I have not yet been able to get the broken stud out of the head. I welded a nut to the protruding part and got it to move about 1/2 turn. I moved it back and forth about a dozen times before the weld broke and the nut came off. It seems like there is carbon on the threads and it makes the threads bind up. I noticed that the studs on the Low Pressure Intake Valve Cover (very little Carbon in LP Valve Cover) came out easy and the ones on the Low Pressure Exhaust Valve Cover were VERY hard to remove. Is making the broken stud very difficult to get out.

I have soaked things in carb cleaner trying to remove carbon. It helps, but does not seem to be very effective. What would work well for removing the carbon?

Oldred, are you suggesting I get/use a brass slinger ring, or just saying that they are commonly used. If suggesting I use one, any idea where to get it?

Suggestions on what oil to use. I have used Amsoil in the past, but it has been quite a while and an entirely different type of compressor. Would Amsoil be a good choice for this compressor?

[Old Fool]

Originally Posted by Joelk

I am in Bedford PA. Not a metro area. About 100 miles West of Harrisburg on the Turnpike.

I think I now have disassembled everything on the pump that I plan to take apart. Except for a bunch of carbon on things, and the "valve cover stud" (and the valve cover it is stuck in) that snapped off when I tried to remove it, everything seems to be in good condition.

I have not yet been able to get the broken stud out of the head. I welded a nut to the protruding part and got it to move about 1/2 turn. I moved it back and forth about a dozen times before the weld broke and the nut came off. It seems like there is carbon on the threads and it makes the threads bind up. I noticed that the studs on the Low Pressure Intake Valve Cover (very little Carbon in LP Valve Cover) came out easy and the ones on the Low Pressure Exhaust Valve Cover were VERY hard to remove. Is making the broken stud very difficult to get out.

I have soaked things in carb cleaner trying to remove carbon. It helps, but does not seem to be very effective. What would work well for removing the carbon?

Oldred, are you suggesting I get/use a brass slinger ring, or just saying that they are commonly used. If suggesting I use one, any idea where to get it?

Suggestions on what oil to use. I have used Amsoil in the past, but it has been quite a while and an entirely different type of compressor. Would Amsoil be a good choice for this compressor?

If you are referring to me, no I am not suggesting a brass ring. Just stating that a slinger ring or dipper ring is a good solid time tested system for low rpm lubrication. Your plastic ring wil most likely serve for the next 30 years if it still appears to not be damaged.

[oldschoolrods]

I don't know of any places in Bedford. Best bet is to try mc master

[930dreamer]

Does your 325 look like this one? Do you have any info on the cfm. I need a new unloader cover. Thanks


locknut, 3/8-24 unf (@ 35 ft.-lbs.)

[Joelk]

Old fool, I had been accustomed to oldred replying. Thanks for the info/opinion.

930dreamer, Mine looks MUCH different. I'm (obviously) no expert on these, but I think yours is newer as it has a different style of head/valve covers. What ROC is it? (should be a # stamped on the data tag after 325) I thought all 325s had an intercooler behind the flywheel(but then again I thought they all had pressurized oiling) Does yours have an intercooler? If so, where?

Sorry I don't know where to get unloader parts. Please let me know if you find a parts source.

[ThePigStye]

I bought this compressor a couple of years ago for $440. Works great, but a couple of weeks ago, the unloader on top of the small piston side started leaking air. I need to find a parts diagram for the unloader, before i open it up. Can anyone help me out here? Has anyone found a source for new unloader parts ?