Got the air compressor going!

[egon]

Any blow by from the crankcase?

Pulling the head may be in order! [img]/forums/images/icons/grin.gif[/img]

You just done used it too much! [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img]

Egon [img]/forums/images/icons/grin.gif[/img]

[Pat]

Any blow by from the crankcase?

Pulling the head may be in order!

You just done used it too much!

Egon

Well good buddy, I think I have to disagree with you this time.

1. It is an oilless compressor so that although it has a crankcase to contain the crankshaft it is not filled (safely fillable?) with oil. I assume (realizing the risk in assuming) that by blow by you mean expelled oil. No oil to expel/blow by. If you mean something else than I don't know how to answer.

2. If it were normal wear over time the degradation in performance would have been more gradual but my situation is that one day it pumps the 30 gal tank right up to 125 PSI and the next it pumps up to 45-47 PSI and although it continues to run it can't make more pressure. When shut off it loses 5 PSI in 3 days, partly due to a reduction in temperature. Now after 4-5 days it is still at about 40 PSI so I think the check valve and pressure switch/head unloader are OK.

3. So, I suppose the "usual suspects" now are: 1. the piston to cylinder wall seal (rings if fitted), 2. the intake and exhaust valves.

I am blissfully ignorant of how the intake and exhaust valves are configured in an oilless compressor (or any compressor for that matter.)

Something other than long term gradual wear effects is at play. Something suffered a catastrophic loss of function as listed in para 3 above.

My alternative courses of action are (not in priority order): 1. Await additional suggestions via this site 2. cannibalize the the unit for the parts that still work (like the tank), 3. take it to a compressor maint shop, 4. open it up and take a look and see if there is anything to be done by someone at my level of competence.

If I exercise action option 4 I will need a source of parts as I suspect there will be a head gasket to renew whether or not I see anything else to replace. I think I remember something about oilless compressors having graphite piston to cylinder wall seals. At least the little used "breathable air" unit I bought from Parson's which was originally used for inhalation therapy but I used for shallow hookah diving was said to have the graphite.

Unless there is something really WEIRD about my situation I feel confident that the problem is a valve, piston seal (ring or ring equivalent), or maybe even a leaky head gasket. If a head gasket blew out (developed a leak) it could cause the overnight change of performance. I know less about the valves than I would like but if a valve developed a problem I think it could have caused the sudden loss of performance too.

I'm open for suggestions, if any, for any tests or inspections prior to pulling the head and looking inside.

Do compressors have flapper valves (reed valves) or do they have valves more like an ICE. It could be something as simple as a mud dauber contaminating the intake valve with gritty mud. When I fired it up to test it the cooling fan for the motor apparently had been colonized by mud daubers as lots of dry mud was slung out with the cooling air flow.

Pat

[egon]

One would just assume you had a proper cast iron head piston compressor Pat. [img]/forums/images/icons/frown.gif[/img] [img]/forums/images/icons/frown.gif[/img] This would fit your tool profile properly. [img]/forums/images/icons/frown.gif[/img] [img]/forums/images/icons/frown.gif[/img]

The type you have I have no experience of ! [img]/forums/images/icons/frown.gif[/img]

Bird will be able to solve your problem. I think the rebuild takes maybe 1/2 an hour or so. [img]/forums/images/icons/grin.gif[/img]

Egon [img]/forums/images/icons/grin.gif[/img]

[GaryM]

Pat, The oil less unit's I've seen, and even my old oiled unit, had reed valves.

Many, if not most, don't have rings either, just a Teflon sleeved piston, of maybe Teflon rings.

[Bird]

I really don't know just what Pat has. I've never seen an oilless compressor that went more than 125 psi, and the ones I have seen all had reed valves and no crankcase at all. The first time I ever tore into one was when mine would only build about 30 psi, continue running, but never build anymore pressure than that. And the problem was a broken reed valve. Instead of a crankcase, there was simply a "crankshaft" directly connected to the motor, the cylinder was a thin aluminum teflon coated cup, and the piston had a single ring.

[GaryM]

Sounds like the Craftsman pancake compressor in my garage. The cylinder's open on the bottom, well the bottom of the piston anyway.

[Pat]

Egon, My first ever compressor came with a length of hose and an old fashioned spray gun and had no tank. It is oil type. When I bought my first tank type unit is was the Devilbiss which recently failed after intermittent use over a period of 15-20 years. It is oil free. I bought the upright Craftsman two stage 175 PSI which recently returned to service after failing within two days of initial startup to provide air for the shop via plumbing, filters, oilers, regulators etc. I probably bought it before I noticed it was oil free and didn't know enough about compressors to know if that was good or bad. I don't know much more now except you acted surprised I didn't have an oil filled unit. I suppose if there is a way to screw up due to ignorance (not knowing that I don't know) I may have done that.

Well it is too late to worry about it now. I will just use the new compressor till I don't care anymore or it dies, whichever comes first. After it dies (if it does) I can cannibalize it for the tank and other parts and buy A CORRECT COMPRESSOR whatever that is.

Pat

[Pat]

Thanks Gary, I have never opened up a compressor but apparently will when I get around to it. Maybe a name brand like Devilbiss will increase the odds of finding parts.

Pat

[Bird]

Pat, the last I knew, DeVilbiss made the Craftsman compressors. And every Craftsman I've seen came with a parts list and exploded view. But since I've not seen any of the 2 stage oilless compressors, I went to Sears website, found one, a model #16778, Sears #00916778000, but could not find a parts list or manual.

[egon]

Pat, I assume things very often. Maybe due to lack of memory or not applying due diligence when reading. Many times these assumptions are wrong. [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img]

Seeing as I have a three HP. cast iron twin cylinder made by Campbell Hausfield I just naturally assume everyone will have a similar type. [img]/forums/images/icons/confused.gif[/img] [img]/forums/images/icons/confused.gif[/img]

Egon [img]/forums/images/icons/grin.gif[/img]