Air Compressor Crankcase Oil

[Neil Womack]

I just purchased my first oil lubricated air compressor. A small 3hp 6.2 CFM@125PSI rated CAPO (PUMA) portable.

Manufacture calls for SAE 20 or 30 weight non-detergent oil.

Is this oil the same as API cat. SB motor oil?

Is my chart reading correct in calling SAE 30 wt. = ISO 100 wt. oil.

With such short change intervals does synthetic oil make any since? We are not talking a lot of oil here 8.5 oz. at each change.

[ November 12, 2002, 10:11 PM: Message edited by: Neil ]

 

[MolaKule]

I assume the compressor is a one or two cylinder reciprocating type driven by an electric motor.

For the past twelve years, I have used Amsoil's compressor fluid in my compressor with one oil change per year. Never a problem and starts in very cold weather without dragging the motor.

I have not, as yet, tried any other brand to-date since I have two quarts left. Once I run out of current stock, I may try Schaeffer's fully synthetic compressor oil.

 

[Neil Womack]

The compressor I'm talking about is a small, 3hp 6.2cfm@125psi Puma compressor, single stage reciprocating. Told you it was small.

I thought about Schaeffers. My compressor takes 8.5 oz per change. Lets see 17 oz per year divided by 5 gallons. Wow a 5 gallon pail should last until 2039 give or take.

Do you suppose Tim will split a pail into half gallon increments?

No really I got the bug in my ear concerning compressor oil when I saw one of the big box store compressor companies advertising that their small reciprocating compressor could be upgraded to 100% duty if Mobil 1 10w30 oil was used.

This made me think these little compressors are not that picky as to what you put in them.

The dealer thinks pretty highly of their own packaged oil. $8.00/quart for mineral oil.

 

[MolaKule]

These compressors are pretty neat. You always have the option of controlling tire
pressures at the house.

I would not put a fully formulated motor oil in the crankcase, as the compressor crankcase
wants mainly an anti-foam additive and virtually nothing else.

 

[Neil Womack]

Maybe a charter member of Oil Analysers Anonymous should submit a sample to test for anti-wear/rust/foaming ingredients.

 

[TooSlick]

Neil,

The Amsoil synthetic compressor oil is available in quart containers. The closest thing they would have for this application is their straight 40wt stuff, which is an ISO 100 fluid - PCK. They also make an ISO 46, SAE 20wt for rotary compressors - PCI ....

Specs are on their website, in the industrial lubes section.

TooSlick

 

[Neil Womack]

TooSlick and Molakule

Thanks guys.

Neil

 

[Bror Jace]

I gave up searching for the perfect compressor oil ... and settled for the stuff NAPA sells. $5 per quart.

My machine is a little bigger than yours ... but only takes 1/2 a quart. I'll change it again in another year or so because it was neglected for so many years before I changed it the first time. I have enough oil left in that 1 qt. I bought.

--- Bror Jace

 

[Bror Jace]

Again, due to recent interest, I thought I'd resurrect this thread.

 

[Steve S]

I used to work at a shop for 16 years that had a huge old compressor that was old when I started there.The oil used was H.D. 30 oil. I'm not sure using automotive motor is bad or good but the compressor lasted. I use motor oil in my 6.5 h.p Ingersol compressor seems to work.

 

[joee12]

Ingersoll-Rand has their own branded oil, the T30 Select, which is synthetic. When used in an Ingersoll-Rand compressor from start-up, you can get up to a five year warranty.
http://air.irco.com/asg/lubricants/all_season_select.asp#

-Joe

[ February 28, 2003, 11:54 PM: Message edited by: joee12 ]

 

[widman]

Although I have a book on which compressors should use which viscosities, in general a recipricating compressor uses a SAE 30 (ISO 100) non-detergent oil.
Many people run engine oils becasue they are easier to find. In the long run they have rust problems in the crankcase, as Compressor oils are desinged to settle out the moisture and engine oils are designed to absorb the moisture so it can evaporate at the high engine temps.
Synthetics are excellent options for these compressors for 8000+ hours between changes or every year or two. My second favorite option is a Group II (Chevron's GST or other), or Group III (Chevron's Hypersyn or other).
Group I products for the average home mechanic is fine as you will never put the 20,000 hours on it that an industry does, but I would change several times a year.
I wouldn't use Napthenic oils, as suggested on one thread. The VI runs around 45, so although you will get startup, it will thin out when you get to the big project. Many people are replacing Napthenic in Ammonia systems with Group II.
Many of the "Brand Name" compressor oils (like Atlas Copco and others are just repackaged oils at 4 times the price.
What is important is the anti-rust and corrosion package as well as the oxidation (D-943 test). I've tested several oils where the anti-corrosion package was used up when it was put in the compressor with the rust already present. Others are much more robust. I've got a couple dozen of analisis, but on this ISP it would take me all day to find them. (running 5 to 10 minutes per page at the moment).

 

[Ken2]

On a past job I was running two compressors, 20 hp. or something, and nearly continuous operation. We'd been using Chevron Delo 1000 40 (a detergent diesel lube) according to the recommendation of our Chevron rep, but we getting bum analyses and dirty valves.

On my own research I switched these machines to a non-detergent turbine type oil, Chevron Machine oil, and picked a viscosity that suited their actual operating temperatures...sometimes 130°F ambient (ISO 220 [SAE 50], if memory serves, and 150 [SAE 40] when cooler). We had better oil analyses and clean valves after that.

The viscosity you pick needs to match your temperature. The guy on a Colorado mountain top will want a lighter viscosity than the guy in south Texas.


Ken

[ March 01, 2003, 01:03 PM: Message edited by: Ken2 ]