Oil blow-by in my air compressor

I have a Sears 2HP/20Gal mobile air compressor that I bought new about 25 years ago when I was a teen. Note that back then, Sears compressors were not sold with over-rated HP claims: mine has a 2HP/15Amp USA-made, Century Motor by Gould Inc.

Even though I've always kept it topped up with air compressor oil, it has succumbed to wear and tear (I admit, I've demanded much more air volume from it that it's capable of delivering, particularly when sandblasting). It now blows a small amount of oil into the tank. Not enough to significantly diminish the oil level in the crankcase, but enough that a milky yellow oil-water emulsion is blown out of the tank drain daily. I can live with a little compressor oil in the air when operating air tools, but it wreaks havoc on my sandblasting (yes I do have a coalescing filter and drain it regularly, but some oil/water is still getting by, especially when blasting for any length of time).

The problem is, replacement parts from Sears are outrageously expensive (at a minimum $75, and perhaps quite a bit more because it's not clear if their ring "kits" include just one ring or a set).

Frankly, if I'm going to spend the money, I'd rather buy a large vertical-tank stationary compressor, but I don't have the space for one now (and with a baby on the way, it's out of the budget).

Any ideas on solving this problem without dumping a lot of money? Are generic rings typically available for compressors (and if so, how do I find the right ones)? Would honing the cylinder walls help? Would a better air filter solve my problem?

Thanks, Michael

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If you can locate a nearby air compressor service shop, they might be able to identify your pump, and supply you with the ring sets and gaskets you'll need.

Cambell Hausfeld? used to be the OEM for a lot of the small portable compressors.

A tool rental shop might also be able to get you the parts kit.

A good, premium quality air filter will prolong the life of new rings, but won't do anything for worn rings. Many of the small portable (and some larger stationary) compressors only have a felt pad to filter the intake air. Fabricating an inlet plate to adapt a better quality filter (pleated paper cartridge type) will provide more suitable filtering.

In most instances, when the air is still warm/hot at the point of use, it will contain excess water and oil. This is especially true with small compressors where the air demand is high, and the point of use is nearby. About the worst situation is where there is only an air hose run across the floor, between the compressor and point of use.

A well thought out air line system will help cool the air, and eliminate most of the water and oil problems in a system with a compressor that's in good operating condition.

WB ................

Reply to
Wild Bill

I have almost that exact same compressor, purchased in 1983. There is an obscure tag down on the side of the motor platform that says "Mfd. by Devilbiss". If yours is the same, perhaps you can hunt down a parts source from Devilbiss that's more reasonable than Sears.

Reply to
Gary Brady

I have a somewhat newer unit but it suffers from the same problem, for the same reasons.

A while back I located a compressor service and the fella I talked to by phone knew exactly which compressor I had and who made it. Unfortunately I didnt record the info at the time.

And even more unfortunately, before I could get the unit in for repair the place went out of business. But I had been told that a complete overhaul would run to about $100 including parts and labor. Quite reasonable I thought.

So if you can locate such a service in your area it would probably be well worth the effort, and if you're like me you'd rather have your old friend pumping away for you than to have a new one :)

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Thanks to all who've responded so far. I'll look for a local compressor service shop.

Well frankly, I'd rather have a 5HP/80Gal (or larger) vertical stationary unit. My "old friend" has served me well, but I'm really demanding more from it than it's capable of delivering.

- Michael

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DeepDiver wrote: snip

Kinda like the Quincy QR325 I just got for $350.00 - nice machine...

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Stephen Young

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