Rebuilt compressor

[pisoiu]

I've managed to put together an ebay purchased mch6 compressor head, a frame built by me and a regular single phase 2.2kw motor. It works like a charm. Due to various restriction in available motor speeds and pulleys, I was not able to obtain the speed at which this compressor normally runs, which is around 2800 rpm. My actual rotating speed is about half, as well as the charging rate.
My question is: since intervals for oil change and for filter replacement are specified in hours, is it wise to consider doubling these intervals since I am working at approx. half charging rate? Or should I keep the same intervals? Thank you.

 

[rcontrera]

There are lots of things that effect the oil but number one is heat. By running slower you are running cooler. Also, by running at lower pressures you will also run cooler.

Oil lubricates, dissipates heat and cleans wearing surfaces. So, since it is still wearing, change the oil as normal. It is better to change too often than not often enough.

HOWEVER ... I would be a little concerned about the speed. That is a splash lubricated compressor. Every time the second stage piston dips down, the flinger pin whips up the oil tossing it all over the inside and the base of the cylinders as well as creating a fog. If it doesn't turn fast enough, it may not lubricate properly. I think you may want to get that little guy turning a little faster than 1400 RPM.

 

[pisoiu]

Thank you. Got it with the oil. The splashing I think works ok. Immediately after I stop the compressor, if I remove the cap from the oil filling cylinder and look inside, it is full with oil up to the top.
About the filter, I am thinking the filter has a certain capacity to absorb impurities, for a certain volume of air, all other parameters (temperature, working pressure) being the same.
So, if I half the charge rate, I think I can double the changing interval, the volume of air processed by the filter will be the same. Correct?

 

[rcontrera]

Sure. If your filter cartridge is good for 30 air fills at full rate, it is most likely good for the same 30 fills at half speed.

However, I again go back to the oil. If it is full to the top, it is too full and is, most likely pumping oil into the separator requiring draining a LOT more often. Plus, if there isn't an oil "fog" being made by the flinger pin, then the first stage piston is not being lubricated.

Your oil level should be between the two marks on the dipstick ... no lower and no higher.

 

[pisoiu]

I am sorry, I did not expressed myself correctly. When the compressor is stopped from some time, the level is between those two marks on the dipstick.
What I meant to say is after the compressor is stopped, when I remove the cap, the inner wall of the refill cylinder is wet with oil, indicating the splash lubrication works. The cylinder is not actually filled with oil up to the top. When I filled the compressor, I used approx. 0,3 liters of oil, this is the quantity indicated in the manual.