I have a united states air compressor MK series that I am about to rebuild. I understand Collins equipment sell parts for them however their prices are extremely high.
I am wondering if anyone has successfully located parts like piston rings, crank bearings , rod inserts by size rather than application. The crankshaft bearings should be easy but I am much less certain about rings and rod inserts.
Second , I'm also looking to change the size of the compressor drive pulley and am wondering if anyone is aware of a source for pulleys by size.
Years ago I was able to source piston rings by size from a Hastings catalog. It wasn't a case of mend and make due either, many of the rings were absolutely dead on size, even when they came from something completely unrelated like a tractor or automobile engine. In some cases, a ring groove had to be widened on a lathe, and for smaller compressors, the second stage rings could be hard to match up, as not many machines used rings that small. I remember once using rings from an Alfa Romeo 2.0l V8.
Sometimes these old compressors had babbit or lead poured directly on the inner faces of the rod big end and clearance was set with shims. Some old Westinghouse compressors did this.
If you are lucky, there might be manufacturers names and numbers on the rod inserts. I know DeVilbiss used Clevite shells in their big ends. Valves might be a challenge, but if you can get the rest of the parts for cheap, splurging on OEM valve bits might be more palatable. Gaskets are easily made, and the oil seal will be an off the shelf part. Really, there is nothing you shouldn't be able to make on a lathe or mill coming out of a small reciprocating compressor. The small end in the second stage might be the biggest issue, as they sometimes wear oblong and can be difficult to fix.
Any size sheave you want for the compressor should be easily sourced, but getting any airflow over the pump would be up to you. Any balancing the pulley provided would be lost, but this is rarely an issue.
