Piston rings leaking on air compressor

[A.K. Boomer]

Sorry but +1 with what Willy stated, it's total hackery at its very best,,,

flow patterns alone dictate only certain sections will get heavily laden with the "crap" whilst others skate almost totally free...

it's junk science and is hillbilly tech. brought to you by people who do not know how stuff works...

hardly leaving nice crosshatch but instead the greatly unwanted linear grooves...

[J Tiers]

Isn't it Bon Ami that used to have a picture of a new hatched chick on the can, with the words "Hasn't scratched yet"?

That was their deal, not really abrasive enough to hurt anything.

[kendall]

Hitch-hiking on this thread.

If I know piston diameter and cylinder diameter, what diameter should I make the rings?

[oldtiffie]

I have a three cylinder single stage cast iron air compressor pump. It is leaking air past the piston seals so it won't build full pressure. Is there anything I can do to fix this problem? I have no idea what make the pump is or from where. Getting spare parts is out. It is blowing some oil from the crankcase into the airstream. I find oil in the air filter on two cylinders.

My guess is that the problem may be related to a blocked crank-case vent/relief valve.

Clean or replace the vent/relief or better yet just take it out and rune the compressor and see if it improves.

[Arcane]

I have never done this either and I highly doubt I ever will. Throwing a fine highly abrasive powder into an engine or air compressor seems unbelievably counter-productive.
I've seen construction equipment engines totally destroyed in a matter of hours due to air filtration devices that where installed wrong allowing fine dust to infiltrate the engine.
Randomly allowing an air compressor to ingest an abrasive goes against every maintenance procedure ever produced.

I could envision a light honing procedure applied properly to the cylinder in conjunction with properly sized rings being beneficial. But the above Bon Ami treatment would leave fine scratches running parallel to the cylinder's bore, exactly what you don't want.

Don't believe everything you hear and only half of what you see.

I found this in http://www.yesterdaystractors.com/cg...alk&th=1262344

Besides honing or etching the cylinder liners, a third method has been used to hasten the seating of new rings to worn liners. This method uses 7F5225 Break-in Powder. The procedure is as follows:

After assembling and starting the engine, loosen the air cleaner to allow a gap between the flange and the inlet manifold. Rune the engine at about 800 RPM and allow the powder to be sucked slowly through the gap and into the engine. Use 1 1/4 teaspoonfuls of powder per cylinder and then tighten the air cleaner. Run the engine at 800 RPM for thirty minutes, and it is then ready for service.


This method of break-in has been used successfully when facilities were not available for honing or etching liners. It has also been successful when, for some unknown reason, new rings and liners have failed to break-in in a reasonable length of time. If the first powder treatment is not effective, a second one may be. However, if the second treatment is not effective, a thorough investigation should be made to determine the cause of oil consumption.


This was taken from the Caterpillar Serviceman's Reference Book for Diesel Engines (5 3/4" BORE 4-CYLINDER) D8800 Industrial, D8800 Electric Set, D8800 Marine, and D7 Tractor.

Form FE031238-01

and

In the early spring 1976 I was in training as a Heavy Duty Mechanic. The Caterpillar service manual that was applicable to the Caterpillar engine we were using as the class 'guinea pig', gave a part number for break in powder, and immediately following that number was the words (Bon Ami) in brackets. Thats right, plain old ordinary household Bon Ami.

[Lu47Dan]

BF, one of my first compressors was an old freon pump from a refrigeration system, when I got it I had to replace the rings in it, I had a friend who worked in a Diesel engine repair shop. He mic'd out the pistons and the bore mearusred the ring width and matched up a set of rings from a motorcycle engine. We honed the cylinders and installed the new rings and put it into service. It outlasted another friends new compressor by about four years. I had less than 10% of the purchase price of his compressor in the parts for mine. I have to say that if you can get the parts for yours and your bores are good than rebuild yours but sometimes it is best just to cut your loses and move on. Save the tank and plumb your new compressor into it for added volume. I have my main from the compressor valved. I shut it off everynight before locking my shop up. I have the compressor's motor control circuit wired into my shops lighting so it will not run during the night.
Dan.

[bob_s]

You guys are going to love this one. I told the wife that the compressor was toast but I think I can fix it. I will order some cast iron and turn three new pistons and make some rings. Hopefully that will solve the problem. She asked if I knew how to make pistons and rings. I told her no but I am sure the guys on the forum will help me get through the project. She looks at her watch and says if you hurry you can get to the tool store and buy a new compressor before they close. And on my way out the door she tells me to buy a good one so I can get some work done and not spend my time fixing my tools. I grab my hat while ringing my hands with a devils smile. I bought a two stage 800 liter per minute constant flow with a 200 liter tank. Compressor head is from a good firm in Italy. The pressure switch is from Condor here in Germany. 3 phase motor 5.5KW. And it is quiet. Not a gloat as I paid full retail.

Maybe I will try to fix the old one just to try my hand at making pistons and rings.

New gloat category? "the wife gloat"

[Rosco-P]

Sorry, one of those cleaning powders with a fine pumice in them used to clean enameled sinks and such.

Ground Feldspar and not highly abrasive.

[Willy]

Before you make new rings you might try the old shady mechanic trick. (Not exactly the same as shade tree mechanic). Assuming that the cylinders are glaze and it's not a case of stuck rings which seems unlikely in a non-combustion machine like a compressor. So you take off the air cleaner, start the machine and then blow about a teaspoon of Bon Ami into the intake. Run for two more minutes and then drain and change the oil. I've never done it, but have heard of it being done.

I have never done this either and I highly doubt I ever will. Throwing a fine highly abrasive powder into an engine or air compressor seems unbelievably counter-productive.
I've seen construction equipment engines totally destroyed in a matter of hours due to air filtration devices that where installed wrong allowing fine dust to infiltrate the engine.
Randomly allowing an air compressor to ingest an abrasive goes against every maintenance procedure ever produced.

I could envision a light honing procedure applied properly to the cylinder in conjunction with properly sized rings being beneficial. But the above Bon Ami treatment would leave fine scratches running parallel to the cylinder's bore, exactly what you don't want.

Don't believe everything you hear and only half of what you see.

[TGTool]

What is Bon Ami?

Sorry, one of those cleaning powders with a fine pumice in them used to clean enameled sinks and such.

[Black Forest]

Before you make new rings you might try the old shady mechanic trick. (Not exactly the same as shade tree mechanic). Assuming that the cylinders are glaze and it's not a case of stuck rings which seems unlikely in a non-combustion machine like a compressor. So you take off the air cleaner, start the machine and then blow about a teaspoon of Bon Ami into the intake. Run for two more minutes and then drain and change the oil. I've never done it, but have heard of it being done.

What is Bon Ami?

[TGTool]

Before you make new rings you might try the old shady mechanic trick. (Not exactly the same as shade tree mechanic). Assuming that the cylinders are glaze and it's not a case of stuck rings which seems unlikely in a non-combustion machine like a compressor. So you take off the air cleaner, start the machine and then blow about a teaspoon of Bon Ami into the intake. Run for two more minutes and then drain and change the oil. I've never done it, but have heard of it being done.

[wierdscience]

With that kind of response you should have more tools break

You could fix the old one,or you could convert it into a good smoker!

[Black Forest]

You guys are going to love this one. I told the wife that the compressor was toast but I think I can fix it. I will order some cast iron and turn three new pistons and make some rings. Hopefully that will solve the problem. She asked if I knew how to make pistons and rings. I told her no but I am sure the guys on the forum will help me get through the project. She looks at her watch and says if you hurry you can get to the tool store and buy a new compressor before they close. And on my way out the door she tells me to buy a good one so I can get some work done and not spend my time fixing my tools. I grab my hat while ringing my hands with a devils smile. I bought a two stage 800 liter per minute constant flow with a 200 liter tank. Compressor head is from a good firm in Italy. The pressure switch is from Condor here in Germany. 3 phase motor 5.5KW. And it is quiet. Not a gloat as I paid full retail.

Maybe I will try to fix the old one just to try my hand at making pistons and rings.

[wierdscience]

Short of tearing it down and putting rings in it no.You could possibly pull it down and match the rings up with something standard,maybe look for a local engine rebuilder that can order stock rings.Or since you have a lathe,maybe get some cast iron stock and make your own rings.If there is cylinder damage you could also sleeve them and bore/hone them back to standard.

Or if you don't want a new hobby scrap it and buy another one.