Air compressor oil

[Paul Janke]

I have two compressors in my shop which together are my air source. The small one is single stage single cylinder and is being powered by a 1725 rpm 1 hp motor and the other is a two cylinder two stage 3 hp, also powered by a 1725 rpm motor. Both of them are probably no less than 75 years old, and could well be over 100 years old. I have read here than automotive engine oil is not good to use in them because of causing carbon buildup on the valves. What oil should I use? Is synthetic compressor the right thing to use, and what viscosity is appropriate? They generally get limited use, but sometimes run almost nonstop for over an hour at a time when using the plaz cutter on production work. I do not want to harm them because of improper lubrication. Thanks in advance.

 

[Steve@Advance]

I used to maintain an assortment of ancient compressors.

Ran them on conventional non detergent compressor oil.

Always had oil consumption problems and carbon fouling the valves.

After some much needed TLC, I got the oil consumption under control, but the carbon problems persisted.

I finally converted them all over to 100% synthetic 30 weight reciprocating compressor oil.

Never had another problem with carbon.

That convinced me, now I use only synthetic compressor oil.

 

[barwinn]

Amsoil compressor oil is a good choice. Worth the cost.

 

[Stephen Newell]

Automotive oil doesn't cause a buildup of carbon, it's the same oil as compressor oil but without the detergent. They put a detergent in automotive oils to help clean the engine but with a compressor it's such a small amount constantly being slung by the rods it tends to foam. You can use a non-detergent oil however that could easier be found with an oil labeled compressor oil. Tractor supply sells it.

 

[Dusty MI]

Hydraulic oil is non detergent oil.

 

[Ellis Kinney]

Amen, what I use. Ellis

 

[moresmoke]

Just to note, if you have any filter regulator units with plastic bowls, the synthetic oil will cause them to crack.

 

[C.Amick]

I just bought some non-detergent 30 W compressor oil from O'Reilly Auto Parts. They didn't have it in the store and had to get it from their warehouse. It was $8.00 per quart or $16.00 per gallon. They also have synthetic at $18.00 per quart..
Compressor Oil