I'm looking to clean up the carbon build-up or other "gunk" on the air-side high-pressure outlet check valves and associated passages on a Westinghouse 8-1/2-150 CC. It's mounted on the loco and fully plumbed.

I understand that a common historic method for cleaning air compressors was to dip the whole compressor in a tank of lye. This option is not feasible for our shop, so a more targeted solution is desired.

What alternate historic methods and materials, or even more modern methods and materials can you recommend?

Also, there's been some talk of operating the compressor on air rather than steam. I understand that one probably could not learn much about the compresssor's performance by doing this, if it even works. Is such a test reasonable as a high-level indicator of major problems?

Thanks in advance,
Bob Milhaupt
IRM Steam Department volunteer

The lye process is described in Bulletin 5036 (March 1923) as follows:

"It is an aid to good operation to thoroughly clean the air cylinder and its passages at least three or four times a year, by circulating through them a hot solution of lye or potash in the proportion of 2 lbs. of potash to one gallon of water. This should always be followed by sufficient clean hot water to thoroughly rinse out the cylinder and passages, after which a liberal supply of valve oil should be given the cylinder. Suitable tanks and connections for this operation can easily be arranged in portable form."

So they advocate circulating the solution through the air cylinder with a tank and pump. They then go on to warn never to put kerosene in the air cylinder to clean it.

For all the Wabco bulletins I have on air compressors from the 1920s through the present, the only accepted solvent for use in cleaning compressor parts (in shop overhaul) is mineral spirits.

PC

Manually clean your check valves and the seats. Then run a synthetic air oil for a while, this will clean the carbon build up. Try Anderal synthetic air oil. After the compressor is clean you can switch to a carbonless oil from Interlube. Reason to go back to a standar oil is that the synthetics are hard on the gaskets in your airbrake system. The carbonless Interlube oil will not leave carbon deposits. Also check the lift on your check valves after cleaning, if the lift is short then they can overheat causing carbon build.

Running on air will permit you to learn if it runs at all - but you will need a good supply of air and a large reserve tank. If it cycles well, use a dishwashing liquid solution sprayed on the joints and glands to check for leaks. You will need steam to do a proper orifice test, assuming you want to go that far - if you are insular and run very few cars, you can just do a running test to make sure it makes adequate air (with a reserve) for your purposes.

Bob K is dead on about manual cleaning, but you might want to include checking the lapped in surfaces of the valve and seat as well as the lift. Something like Prussian Blue is easy for that. If you use good brakes like 6ET of K14, you won't have gasket problems in the brake valves from synthetic oils except perhaps for mounting gaskets on the reducing and feed valves. Later brake systems with nonmetallic gaskets, yes you will have some problems.

Good luck - have some fun with it, it's pretty interesting stuff to work on.

dave

Dave,

We're working with 6LT, and will need to pass an orifice test (once we have steam up). I spent a few days recently re-learning how to use my lathe then making up an orifice tester and orifice disks patterned after the one shown in period Westinghouse documents.

All,

Thanks for the advice and suggestions.

Further information is welcomed - we are not likely to work on this for a week or so.

Regards,
Bob

The method I have used for this process is old and rather crude but tried and true. It does require a bit of plumbing and having the engine under steam although you could run the pump on air for this procedure and find another way to heat the cleaning solution. It works much faster and better when heated.

Set up a drum (55 Gal. works well) under the pump. Remove the air filter and disconnect the air discharge line at the pump. Disconnect the lubricator lines to the air cylinders and plug the port openings. Run pipe from the air intake manifold and the air outlet down into the barrel. Make certain that the return pipe from the air outlet on the pump goes far enough down into the barrel so that it will discharge below the surface of the solution or it will cause excessive foaming. Connect a coil of copper tube to the drain valve on the low pressure steam cylinder and lay the coil down in the barrel with the free end placed so that it will drain outside the barrel. This serves as a heater for the solution.

Fill the barrel about half full with the lye solution. Run the pump very slowly, just a few strokes per minute, for several hours. Regulate the low pressure steam cylinder drain valve to allow a small amount of steam to circulate through the heating coil. This will circulate the solution through the entire air portion of the pump and thoroughly clean all the passages and check valves. After using the lye solution circulate clean water through the pump to flush it out thoroughly then run it for a while to get all the water blown out.

After cleaning, remove all the check valves and check for general condition, proper lift, and foreign material in them. When all is done run an ample amount of clean carbonless air oil through the pump to lubricate everything again.

Carbon build up is much less of a problem if you use the proper air oil and a good intake air filter but, depending on the amount of service and operating conditions of the pump, it will still be necessary to "launder" it periodically.

Bob said the magic words: Interlube Carbonless Air Oil. Good stuff!

Ever see a gunked and carboned-up set of small block chevy cylinder heads or a block after being rebuilt? Clean as a whistle. Many engine rebuilders have lye vats or other rigs which spray hot solution from all directions. If you have a compressor off the locomotive, you could tear it down and take it to them.

Paying for their service, rather than dealing with the potential liability of keeping a lye vat on the property, would be worth it.

Russ hit the nail square on the head so to speak. The method he describes is practically word-for-word how Westinghouse described how to "launder" compressors.


DC

Friends,

At this time, we have not decided whether we will run lye thru the air-side. We plan to clean the check valves and cages, and inspect the seats and lift. Then we will probably attempt to exercise the air compressor by applying air to the steam side.

For such a test, air-side lubrication would be the same as in normal operation. But lubricating the steam-side isn't so obvious.

I presume that air-side oil would do bad things in the steam-side unless thoroughly cleaned before running on steam, but am clueless on how to clean it out. (We do not intend to take the compressor apart between now and any steam test.) I presume that applying saturated-steam cylinder oil to the air supply would provide insufficient lubrication to the steam-side components, as it probably would not atomize in the relatively low-volume and cool air supply.

What options should we consider for steam-side lubrication when using shop air on the steam side? Suggestions are appreciated!

Regards,
Bob Milhaupt
IRM Steam Department Volunteer

You could use vegetable oil, which will be very rapidly blown out by the steam - which will be well under the flash point of cooking oil - and somewhat miscible in hot water for test lube. Alternative is to use steam oil, which will work OK even if a bit stiff when cold. I think you are overthinking this bit. The heat which carbonizes is the heat generated by compression in the air end, the steam end is fairly immune to that sort of nonsense unless run with high friction or gunky lube. Straight mineral oil of about 30 weight from the auto parts store will be fine for test lube, but I'd certainly douse the main valve through the top cap with steam oil before starting on steam when you go into "real" service.

dave

Bob,
I use Marvel Mystery Oil to lubricate the steam side while testing with air with great results. Just remember to not add too much oil as it could cause hydraulic lock. The Marvel will do a great job of cleaning out interior gunk as well. There should only be a slight film of Marvel left behind after the test.

Bob
How long do you plan to run the compressor on air? Diesel oil should be just fine for a lube while running on air and still wash out when you apply steam later. Kerosene should work as well. If this air test is just for a short time then the residual steam oil should be sufficient

When you lay up after running then the compressor steam side should be blown out and lubed. We have found that charging the boiler on air to 110 PSI then running the appliances does a OK job. After this while you still have air on the boiler add water soluable oil into the steam oil lube check, about a half pint or more, then run the compressor a few strokes. This will displace the water and apply a protective lube coat on the important parts.

Wow, did this topic take me back, this was a very funny episode that happened to me. Back around 1969 we were experiencing air pump problems on Quakertown & Eastern #4 (ex-BC&G #4) at the Reading's Saucon Creek roundhouse in Hellertown, PA. One of the Reading's old heads suggested hooking it up to a compressor laundry which we did. We cooked out so much gunk that the pump was worse than before - the carbon was what was holding everything together. Well, we ended up ordering new rings, valve cages, valves, packings, etc.
Oh, and did I mention I had to buy a new pair of boots?
Don Fenstermacher

I have a collection of picks made from old machinist's scribes and heavy music wire that I use to clean out the baked on deposits from the passages once the valves and seats have been removed. It would be helpful to have a 5 gallon bucket of patience on hand as well. Most of the deposits are near the valve itself and are easily reached with picks. I also had the use of a bore-scope to assist the location of the heavy deposits up inside the horizontal passages at the bottom of the pump. Now that I have done it once, I know where they hide and probably wouldn't need the scope.