Advice on replace or repair CH compressor pump

[jbontke]

SHORT READ: I bought a used 60gal compressor for $200. got it home and noticed it had probably fell over. Disassembled and saw it had a cracked cylinder. Add up the parts for repair and it's $160 to fix the one cylinder, $230 if I replace the rings for the whole pump. Continue to the options:

LONG READ:
I bought a Campbell-Hausfeld air compressor off craigslist for $200. Model number DP461500AJ. It has a 60 GAL tank and the label says 7.5HP peak motor (230v), 13.5 SCFM@40PSI, 12.x SCFM@90PSI all at 135 max PSI.

Here is a link to the parts list: http://www.ereplacementparts.com/ca...air-compressor-parts-c-32345_32346_33016.html

The unit is about 7 years old from what the guy told me, was used in an upholstery shop. Seemed like a good deal, heard it run, noticed it had a faint pop/knock sound and thought it was the one way check valve.

Closer inspection at home shows that one of the cylinder heads had fins missing. I think it fell over. From the link above you can see it has 3 separate cylinders, one sticks out on the edge and it took the fall. I plugged it in, ran it, and it knocked. More like a metal to metal knock. So I decided to pull it apart.

First I took off the cylinder heads off the center and side with the busted fins. I noticed the piston in the cylinder with the broke fins was more oily and dirty than the center piston. Next, I clean the old gasket off each cylinder and set a straight edge across the top of each cylinder. When I turned the crank, the cylinder with the busted head hit the straight edge. The other did not. Then, I pulled the cylinder off the side with the busted head and inspected it. I found a hairline crack at the base of the cylinder. ****.

The rod/piston had no slack or unusual movement at the crank or wrist pin. How the piston was hitting the cyl head still eludes me. The piston is not cracked nor was it damaged. The cyl head and piston have small marks from where debris were hitting them, but it does not concern me enough to replace them. At this point, I don't know how much further the damage went, if any. I am really surprised the piston was hitting the cyl head. The cylinder must be jacked or someone previously took it apart and did and did not use the correct gaskets (thickness possibly?). So repair is a slight gamble.


OPTIONS:
So I started weighing my options on repairing this and getting the compressor working. here they are as follows:

1.) Repair the compressor by replacing the parts from the link above. If I replace the cylinder, gaskets, piston rings, etc it will cost from $160 (replace one set of piston rings) to $230 (replace all rings).

2.) Replace the pump with a similar unit (HF has a cheap unit for about $150). However, I have not been able to find a pump that offers the same SCFM as what this unit was stated to have (13.5 SCFM@40PSI, 12.x SCFM@90PSI) assuming it was not over stated at the time. Link to HF pumps: http://www.harborfreight.com/catalogsearch/result?q=compressor+pump

3.) Contact a local compressor repair shop and see if they will take the old pump as a form of trade for some $$ and get a rebuilt (hopefully better quality) pump. I have no idea on the cost on how this option would go. Experience with this would be appreciated.

The motor (230v, 3450 RPM) is rated at 17.3 amps. I did the math (17.3 * 3450)/748) to determine that its 5.31 HP motor. However I keep hearing that 17.3 amps is more like 3 HP. I am not sure if I need to choose a pump that is rated for 3 HP or 5 HP motor. I would like suggestions on this too, please.

So what is the consensus on the dilemma?

Thanks,
John

CYL CRACK

GOOD PISTON:

DAMAGED CYL PISTON

MOTOR

 

[Davefr]

First of all, CH is lying about the HP rating. At 17 amps you have a 3HP compressor.

IMHO, I would not spend $200+ to repair a 3HP pump. It's also a gamble unless you can pinpoint every worn or damaged part.

Unfortunately the only low cost replacement pump options are from HF. You'll find that prices quickly jump to around $500 after the HF pumps. However reviews aren't too bad on their pumps.

I'd probably get the 3HP HF pump and make sure you drive it at the correct RPM. (use a coupon if they allow it on pumps)

You might also take a peak at CL to see if there are any good used pumps out there.

Anything else and you're putting "lipstick on a pig".

 

[jbontke]

Yes, this compressor was sold during those days when the numbers were elaborated to sell the compressor. It has a sticker advertising 7.5 (peak) HP, 13.5 SCFM @ 40 PSI and 12.x SCFM @ 90 PSI, 135 PSI max. I am curious about the CFM though, it is more likely 10 SCFM @ 90 PSI?

I was also thinking about running a better, higher quality pump that requires more HP and spin it at a lower RPM until I can upgrade to a 5HP motor. I was looking at an Eaton pump which, in theroy, could do that with: http://www.eatoncompressor.com/catalog/item/518643/184117.htm

Then I have to start looking at what I paid for the CH compressor and decide what I really want to invest in it. The long term goal is to purchase a 2 stage 7.5HP Quincy compressor. I bought this CH because my blast cabinet was exhausting a small 115v compressor. I need 7 CFM to run the blast cabinet..... decisions, decisions.