Old Mills Compressor Oil Level

[dave parker]

I have an old MILLS compressor that I cleaned and repainted. Looks great. I want to do an oil change. There is no site glass or dip stick. I need to know what level the oil should be. Should the oil level with the bottom of the crank, Oil level in the middle of the crank, Or oil level below the crank. You can see the oil plug on the side of the pump. It is pretty high, almost level with the bottom of the crank. I searched the internet and cannot find much about this compressor or the oil level.
Thanks, Dave Parker

 

[rons]

My compressor pump has a site glass. It bolts onto a flat with two fasteners. When the oil level shows full the
oil is about to spill from the fill hole. You may find a flat on the pump for a add on site glass.

Makes sense, not possible to over fill the oil unless the pump is rotated from level.

Those little projections on the cylindrical portion of the crankcase. Their height (on each side) are in line with the filler plug.
Those are probably mount points for a add on gauge.

 

[52 Ford]

I have an old MILLS compressor that I cleaned and repainted. Looks great. I want to do an oil change. There is no site glass or dip stick. I need to know what level the oil should be. Should the oil level with the bottom of the crank, Oil level in the middle of the crank, Or oil level below the crank. You can see the oil plug on the side of the pump. It is pretty high, almost level with the bottom of the crank. I searched the internet and cannot find much about this compressor or the oil level.
Thanks, Dave Parker

Cool compressor! All of the splash lubricated compressors that I own have the oil below the level of the crank case. In fact, I don't believe I've ever worked on one that had oil up to the crank. It puts extra stress on the seals and/or makes it more likely to leak oil. It's hard to tell from the angle that the picture is taken - if the top of that fill port is below the crankshaft, I'd fill it up till it started to run out, just like you'd do with a small engine.

 

[Bill D]

Did the crank have dipper like some Briggs & Startton engines do?
Bill D

 

[john.k]

Looks like a refrigeration unit to me......oil circulates as a foam with the freon ,to some extent.

 

[dave parker]

Cool compressor! All of the splash lubricated compressors that I own have the oil below the level of the crank case. In fact, I don't believe I've ever worked on one that had oil up to the crank. It puts extra stress on the seals and/or makes it more likely to leak oil. It's hard to tell from the angle that the picture is taken - if the top of that fill port is below the crankshaft, I'd fill it up till it started to run out, just like you'd do with a small engine.

The bottom of the fill hole is level with the bottom of the crank shaft. Thanks for the guidance. Dave P.

 

[dave parker]

Did the crank have dipper like some Briggs & Startton engines do?
Bill D

Don't understand what a dipper is. If you are referring to a dip stick, nope. No dip stick. Dave

 

[dave parker]

Cool compressor! All of the splash lubricated compressors that I own have the oil below the level of the crank case. In fact, I don't believe I've ever worked on one that had oil up to the crank. It puts extra stress on the seals and/or makes it more likely to leak oil. It's hard to tell from the angle that the picture is taken - if the top of that fill port is below the crankshaft, I'd fill it up till it started to run out, just like you'd do with a small engine.

Thanks, I was thinking at or below thew height of the bottom of the crank shaft. Dave

 

[Bill D]

Don't understand what a dipper is. If you are referring to a dip stick, nope. No dip stick. Dave

Dipper is a small sheet metal piece that also locks rod nuts. It sticks below the crank and goes into the oil to sling it around. AKA slinger.

 

[52 Ford]

Dipper is a small sheet metal piece that also locks rod nuts. It sticks below the crank and goes into the oil to sling it around. AKA slinger.

They can be part of the casting, too. Here a picture of one from Honda GX 240. https://www.carbydoctor.com.au/assets/full/CR110.jpg?20200703030949

 

[Bill D]

If designed properly they sling oil up the sides of the case into some small cast in troughs that run the oil down into the bearings. My Harrison m300 lathe does this to just from oil thrown off the gears in the headstock up onto the main spindle bearings.
Bill D

 

[cnctoolcat]

Yeah man, like said, fill the oil until it runs out the fill hole, then plug it back. And fire it up!

ToolCat