Compressor refurbishment

[Brainsparks30]

I got a fairly big old compressor that I intend to refurbish. There is no makers plate so specs are guesswork. Very little output when turning the wheel by hand, so I suspect duff valves. I found a video on polishing them back to good condition, but I'm assuming the worst case scenario.
I don't have it apart yet.

Is there a place you can get internal spare parts from according to size, rather than manufacturer?
Also, is there a rough way to gauge how much Hp motor ought to run it? Is there such thing as too much? Is rpm a factor?

 

[MattF]

Photo of the compressor?

 

[chris y]

I cant answer many of your questions, but pics would be a good idea.

One thought though, valves isn't worst case, if the piston / rings / bore are worn out it probably wont be worth repairing, although a whole new pump can be affordable if the rest of it is OK.

Is there no motor present now?

 

[rtbcomp]

RPM is a factor, not enough and you won't get full output, but if the pump goes too fast the piston will be on its way back down before all the air is expelled from the cylinder so again you'll lose output. Going too fast may cause mechanical issues and overheating. Fitting a motor that is too powerful doesn't matter, fitting one that is underpowered will lead to loss of output and possible damage to the motor.

If you take the head off measure the bore and stroke, that way we can work out the displacement and from that a ballpark figure for the size of motor.

 

[Brainsparks30]

Pics are up.

No motor, I shall have to source. Planning a three phase setup 3HP+ with VFD.

Measured cylinder with (cheap) caliper - Bore 63.46 mm, stroke 90.24 mm.

Oil looks really old.

I guess now that it could be making the air it should, but I cant spin the wheel fast enough to notice.
All a journey for me, hope to learn new things.

 

[rtbcomp]

No pictures.

Why do you want a vfd on a compressor?

 

[WorkshopChris]

With just a turn of the fly wheel you should normally be able to feel a suck and blow with the palm of you hand over the inlet/outlet.

 

[frank horton]

u'd be surprised how much crud get stuck around the valeves.......if it's an old cast iron thing that been kept full of oil it'll prob last for years........
just wire it up and give a run........never heard of polishing compressor valves......
guess for the last 20-30 years they were stamped out of stainless.......the old 1's were high carbon steel.......
still never a problem........
good luck......

 

[Brainsparks30]

Pics confused me too, you got to right click link and paste in browser for photo bucket.

As for the VFD, I found this on AVE's channel

Profane, but good!

It doesn't have to be VFD, but I like the idea.

Polished valves, or lapping

It is producing some air, I will give it a clean and see.

 

[ukracer]

RPM is a factor, not enough and you won't get full output, but if the pump goes too fast the piston will be on its way back down before all the air is expelled from the cylinder so again you'll lose output. Going too fast may cause mechanical issues and overheating. Fitting a motor that is too powerful doesn't matter, fitting one that is underpowered will lead to loss of output and possible damage to the motor.

If you take the head off measure the bore and stroke, that way we can work out the displacement and from that a ballpark figure for the size of motor.

Oh no.......