On second look at this compressor -- it is a 3S4 compressor. It is indeed a Hamworthy but it is a 3 stage not a 4 stage compressor. They are notorius weak in the 3 stage and used ones sometime have difficulty pumping more than 3000 psi. Maximum rated pressure new is 4200psi
frogman62
sheldensportinggoods.com[/quote
The photo of the unit at the start of this link is a 4s4 not a 3s4
3s4 final stage faults [un due wear]
most times can be traced back to a worn top cross head pin or con rod bush.
this makes the final piston try to run out of line. also the final piston is not reaching the top of it stroke TDC.
its no good just replacing the worn piston /liner,it will not last long.
with the final stage removed,set cross head to TDC,the try to check for any play in the con rod top bush.
some mods have been done over the years and bushes are no longer used on top of both con rods.
any one that wants more info on mods to top bearings PM me
