I have about a 25 year old 4 HP 20 Gal Tank Craftsman Air Compressor that still puts out air but it knocked pretty loud. I decided to put a Northstar Pump that I purchased from Northern Tool. On sale and free shipping.

Craftsman 4 HP SCFM @ 90 PSI = 7.7 (919.177541) (Aluminum)
Northsar SCFM @ 90 PSI = 13.2 (45930)(Cast Iron w/Aftercooler & Oil Level Sight Glass)

To install the new pump I had to get a new drive sheave (AK59H W H 5/8 Bushing) to run the pump at the recomended RPM of 1450. Calculate the belt dia. = A54 Napa., Drill 3 mounting holes on the mounting plate of the tank. Run new tubing from the pump to the tank run tubing from the tank line to the unloader. It took me a while to settle on how to run the piping but a few trips to home depot and looking at the hook ups at the compressors at Harbor Freight I believe I came up with a good set up. I drilled the 90 degree tee fitting for a 1/8 pipe thread and installed a 90 degree 1/8 NPT to 1/4 Compression fitting. I also installed a 90 degree 1/2 NPT to 1/2 Compression fitting at the pump outlet. The tubing was 1/2 OD Soft Copper Tubing that I purchased in a 10' foot roll. I ended using quite a bit of tubing due to trying to use a cheap hand bender from harbor freight.

 

I switched to compressiion fittings so I could get the discharge piping closer to the face of the pump. I switched the unloader plastic tube to copper due to the plastic heating up and popping off. I added a universal belt guard that I purchased on ebay. The transformation is now complete. Since the northstar pump puts out more CFM than the craftsman pump I am now able to run a blast cabinet. I purchased one from harbor freight tools. The blast cabinet was on sale for $199, plus I had a 20% off coupon so I got the blast cabinet $159 + Tax out the door. Attached are pics of the completed transformation.

 

Sweet, I need a good compressor for our 2nd Garage, I have air tools but can't use them in the back, and the compressor we have is too big to start lugging back and forth from the attached garage in front to the detatched in the backyard.

 

Nice job!

I'm still waiting for a friend of mine to see if he can setup a VFD so I can use the 3 phase 5HP motor that came on my compressor. I gotta give him a call.

 

Thanks, I could not have bought a new complete compressor with simular specs for the money I have invested in putting a new pump on the existing tank.

 

Yeah, I'm trying not to spend any additional money over the $150 I spent on this puppy.