draper 50L 2hp compressor - Burnt oil

by Matt
(Cambs)

Hi - I have a draper 50L 2hp compressor. I have noticed that it is getting very hot and the oil is very black and smells like it is burnt.

Tried changing the oil and going again but it just blackens it and smells still.

The cooling fins on the cylinder and head will get hot enough to burn your skin if the compressor is run up from empty.

Removed the head cylinder and piston to check for damage or scoring and they are all smooth and look ok to me. The bottom end is fine too and i am at a bit of a loss as to what to check next.

Any ideas?

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Bill says...

Matt. You've pretty well covered all the diagnostics I would do.

One thought... is the motor on the Draper air compressor direct coupled? Is the motor itself getting hotter than normal. It's a bit of a stretch to think that there would be enough heat transfer to the pump to the sump to burn the oil. However, I would check anyway.

Another thought. Shut it down, drain the air, and check the CHECK VALVE going into the tank. If it's jammed the back pressure might cause your air compressor to run hotter than normal.

However, I really do think you have a metal to metal friction issue, based on the amount of heat you are referring to.

My two cents worth.

Cheers,

Bill