Tim's New Workhop thread.

[Dieselfitter]

2nd stage piston. Gummed up rings

 

[Yukon Stihl]

I bought and installed a cheap back up compressor to run while I repair this one. Now I have more time to fix this one.

I've been wondering what caused the bearing scoring. Was it run out of oil or lack of maintenance? It seems it was lack of maintenance. There is oil sludge in the crankcase and oil varnish on the stuck piston rings. The discharge valves are pretty rough at least 2 of the 3 need complete replacement. I think it will cost about $2k in parts to fix. I see replacement compressors, pump only for $11k. This thing is pretty big for a reciprocating compressor. It is rated at 55 cubic feet per minute at 175psi.

My guess is lack of maintenance. Hit the switch walk away.
Till it doesn't pump air, then WTF

 

[Dieselfitter]

The discharge valves are pretty rough. There are 3 of them. 2 for the 1st stage, 1 for the 2nd stage. They set in a pocket in the head and have a cover with a jam bolt holding them down tight. The 3 are in progressive stages of failure.
Here is the only one that can be re-used. I'll blast the rust and lap the seat. The shouldered bolt holding it together wasn't very tight.

 

[Dieselfitter]

The bolt on this had come loose and hammered the threads off.

 

[Dieselfitter]

This one had been hammering for a while. The bolt had migrated through the bottom and been hammering into the piston.