Compressor Buying Advice

[RobertN]

Hey Bird,
How do I know when to rebuild an oilless? I have a 5hp 60gal DeVilbiss Pro-4000. It's at least 6-7 years old. It's LOUD. It's been used for running sanders, air nailers, air ratchets, impact drivers ect. It seems to work fine, although, did I mention it is LOUD? I'm not sure how to decide if it's time to replace the teflon pistons.

A secondary question. I have the electric motor, shut-off, and twin-cylinder cast iron setup from my old compresser. The old one had the tank go bad. I threw the tank away, but saved the rest of the stuff. Could I use a 5hp motor to drive the old compressor cylinder, to a higher capacity that the 2hp motor did? Could a 5hp motor drive the compressor faster, or something? Would a 5hp compressor setup use bigger cylinders than the 2hp?

I have wondered about pulling the oil-less setup off the newer compresser, and using the old Sanborn twin cylinder setup(it was a Sanborn 2hp twin ccast iron cylinder, with I think a 20gal tank) with a bigger motor.

 

[Bird]

</font><font color="blue" class="small">( How do I know when to rebuild an oilless? )</font>

I only did mine when it broke something. /forums/images/graemlins/laugh.gif However, if it's getting noisier, it might also be taking longer to build up its pressure. Personally, I'd say rebuild it when you can't stand the noise anymore or when it doesn't work anymore. /forums/images/graemlins/wink.gif

My experience has only been with "stock" compressors; never tried changing to bigger motors, etc. However, no reason the 5hp motor couldn't work on a compressor that had been run by a 2hp motor. If the pulleys are the same size so the compressor is turning the same RPM, I doubt that you'd notice a difference. I don't doubt that you could either adjust the pressure switch or replace it with one that would let a higher hp motor build a higher pressure, but I don't know whether the compressor would hold up for that or not. And I would expect a compressor that came originally with a 5hp motor to have bigger cylinders than one that came with a 2hp motor, but I don't know whether that's always the case or not. Of course, if I already had the stuff that you have, I sure might give it a try.

My brother once brought me a broken 60 gallon rig with a vertical twin aluminum compressor to see if I could fix it. The guy who had owned it had pulled the oil plug and could "see" oil (or at least he thought so), but it was such a shallow crankcase that he was just seeing the oily bottom. Those have to be filled right to the brim. So he had run it until parts started melting, and while I certainly could have fixed it, the parts would have cost more than just putting a whole new compressor on it. Instead my brother sold the tank and motor to a mechanic who had a compressor with a rusted out tank.

 

[slapshot]

Just my 2 cents on oil free compressors...a couple weeks ago my trim carpenter was using his Bostich oil free pancake compressor when the cylinder had exploded!
From the best we can tell the handle to carry the thing was directly attached to the top of the cylinder head, between the stress from carrying the thing and the piston it shattered!
I've never seen anything like it.
Unless you need you compressor to work on an unlevel surface, oiled compressors are the only way to go.

-dave

 

[_RaT_]

Robert, I'm selling my 5 HP 80 gallon IR. Its practically new. /forums/images/graemlins/wink.gif

 

[Bird]

Dave, in addition to broken reed valves, worn out piston ring and cylinder, one of the things that happened to the last oilless one I had was that the plastic squirrel cage fan broke loose once. If you want to hear one that's really noisy, wait until that happens. And it cracked that pretty black cowling before I could get it shut off. I posted a message back then that the cowling serves two purposes: (1) If you saw what was under there, you wouldn't buy it, and (2) it keeps it from throwing parts at you when it blows up. /forums/images/graemlins/wink.gif /forums/images/graemlins/laugh.gif

 

[SonnieP]

I just replaced my old compressor (Black Max 10 gallon with a 3.5HP motor) of 20+ years... I think it was oiless because I never oiled it. That may be why it only lasted me 20 years. It got moderate use. I suppose if you figure 1/10th life then an oiled one will last you 200 years... lol.

I picked up a 15 gallon 1.7/5HP Campbell Hausfeld at Wal-Mart for $200. It's much quieter than the old Black Max. It has wheels and stand on end for space saving if needed.