help plz: changing oil on old compressor pump

[Mandres]

I just scored an old Speedaire compressor off Craigslist for $40. It needs a new pressure switch, which I've already ordered, and I thought I'd go ahead and clean up the pump and change the oil. I don't have a manual, and have had no luck finding one, so I was hoping someone here could help me out. This is a picture of the pump, you can see the two screws in the base. I'm assuming the horizontal is the oil drain, but I'm not sure. I'm also not sure where the fill hole is, and I certainly don't see any kind of dipstick. Is this the type where you just fill until it overflows? If so, would the top screw be the fill hole?

Thanks

http://i47.photobucket.com/albums/f158/Mandres/Pump1.jpg

http://i47.photobucket.com/albums/f158/Mandres/Pump2.jpg

[Uncle Buck]

You are correct in your assumptions. The horizontal plug is the drain and the vertical one is the fill hole. I think you will find that 30wt motor oil is what you need to use to refill that pump. Good luck.

[engnerdan]

I have heard that you are not suppose to use motor oil in a compressor because it can combust under pressure and heat. I don't know if it is true but compressor oil is not all that hard to come across so I would just use the right stuff.

Dan

[Uncle Buck]

I have heard that you are not suppose to use motor oil in a compressor because it can combust under pressure and heat. I don't know if it is true but compressor oil is not all that hard to come across so I would just use the right stuff.

Dan

I told him that because some time back I had to drain and transport a wheeled compressor in the trunk of a car. It was a sears compressor of probably 1970's vintage and looked very much like that pump. On my compressor it directed that the pump be filled with 30wt motor oil. I also recall that my first purchased as new CH compressor in the mid 80's called for the same thing. In no way do I claim any expertise, I simply shared what I had done by manufacturers instructions on like sized compressors in the past.:beer:

[eschoendorff]

You should be fine with any non-detergent 30wt oil. Actually, you can go to TSC and buy actual air compressor oil (not air tool oil) if it makes you feel better....

[goodfellow]

I have a 1/2HP 7.5 gal Wards compressor of that era (pretty much the same pump) and still have the original owner's manual. In it they recommend 30 or 40wt non-detergent motor oil. It's lasted 30 years --

Yes, you do fill it to the bottom of the fill plug.

[goodfellow]

Just an aside -- My wife just reminded me that about 25 years ago one of our old neighbors borrowed that little 1/2HP compressor to paint his 1970 VW bug (in his driveway no less) At the time the whole neighborhood was laughing at him, but he went ahead with the plan.

Long story short, he shot the whole car with laquer paint using my $19.00 Wards gun and that darn compressor. After it was sanded and buffed, it looked like it came from the showroom. There was a lesson for me -- I learned that careful planning, skill, determination and preparation will go a long way in making up for sub-optimal conditions and underpowered equipment.

Sorry -- didn't mean to change the thread, but just to say that those little Speedaire units were well made, and that many imaginative folks did amazing things with that equipment.

[MXtras]

I recommend using air compressor oil, also. Rarus 427 (?) is good stuff.

I used motor oil for many years until my compressor started using a lot of oil and my supply guy gave me two quarts of Rarus to try. The compressor ran quieter and used less oil. I was sold.

Scott

[SteveU]

Rarus 427 is what came in my compressor from the factory. It has a pour point of 45* F and is unsuitable for use below 55-60* so I replaced it with Amsoil PCK which has a pour point of -49* F and can be run down to below 0*F no problem. If I lived somewhere that it never gets cold the 427 might be an option but last winter when we replaced the struts on the wife's car it was right around 0*F & the compressor would have been unusable without a synthetic oil. Get a good synthetic compressor oil, it doesn't take that much & you can even use it to lube your air tools so it does double duty.