Is my compressor pump wore out?

[kabic]

I bought a used Sanborn 60 gallon Compressor. Im trying to figure out if it's tired and wore out or just not as fast as I was hoping. I can outrun it with die grinder pretty easily.

Model is SL7006016.
12.3 CFM @40
10.3 CFM @ 90


I just timed it and it took 5 minutes 11.72 seconds to go from 80 to 135 psi.

That seems horrible. Should I be looking for a rebuild kit or jump to new 2 piston pump?

 

[finn]

Pop the head and look at the reed valves. I doubt if it’s the rings if it isn’t blowing oil out.

I did a quick check on air consumption on small die grinders a d found 4, 7, and 22 cfm at 90 psi. The 22 seems like an outlier, but that’s what the spec said for that particular CP.

 

[PoorUB]

I bought a used Sanborn 60 gallon Compressor. Im trying to figure out if it's tired and wore out or just not as fast as I was hoping. I can outrun it with die grinder pretty easily.

Model is SL7006016.
12.3 CFM @40
10.3 CFM @ 90


I just timed it and it took 5 minutes 11.72 seconds to go from 80 to 135 psi.

That seems horrible. Should I be looking for a rebuild kit or jump to new 2 piston pump?

11'ish CFM worked out to about 3HP. My opinion is 3HP is a bit short for die grinders, air drils or random orbit sanders. Fine for a hobbyist situation, but it won't keep up for constant use.
I had a 3HP, 11 CFM Porter Cable and was doing bodywork on a car. With my random orbit sander the tank pressure would get down to around 60 PSI, still run the sander and "balance" out at that point.

On the other hand 5 minutes to go from 80 to 135 PSI "seems" to be a long time, but I don't know. There are calculators on the internet that can help figure out the CFM, or tank size of a compressor. You put in known numbers, time to fill, tank size and it will calculate the actual CFM. I would go that route and see what the math says, then go from there.

 

[Sherk]

Pop the head and look at the reed valves. I doubt if it’s the rings if it isn’t blowing oil out.

I did a quick check on air consumption on small die grinders a d found 4, 7, and 22 cfm at 90 psi. The 22 seems like an outlier, but that’s what the spec said for that particular CP.

This!

My dad gave me his old, tired Sanborn 2HP 10 gallon unit that the tank had rusted out on. I was also given an 11 gallon tank that the oilless compressor had failed on by a friend. When I cobbled the two together, it initially took about 11 minutes to fill.

When I took apart the head, I realized the reed valve was covered in thick carbon. I polished that off and cleaned everything and put it back together. That drastically reduced the time to about 2 min 20 seconds to fill.

 

[BobnCO]

I think those older Sanborn compressors are marginal for high volume air tools; compressors are one of those things as soon as you get the affordable one you thought would work (if you really use it, particularly with air tools) you want a bigger one. I worked my way up to current 7.5hp 80 gal. Champion… $550,000 with a “free” shop…

 

[PWC Repair]

That sounds pretty normal for a single piston pump.........that tank is also VERY large for a single piston. If you're actually going to run air tools I suggest a 2 stage pump or at least multiple cylinders.

 

[finn]

That sounds pretty normal for a single piston pump.........that tank is also VERY large for a single piston. If you're actually going to run air tools I suggest a 2 stage pump or at least multiple cylinders.

Math is your friend. He says that it’s a 10 cfm pump at 90psi.

The die grinders I looked up require 4-7 cfm at 90 psi.

They don’t care how many stages or cylinders the pump has, they just need 4-7 cfm.

His pump apparently isn’t putting out that flow, although it‘s advertised as being capable. It’s worn out.

 

[CGT80]

The math is wrong! Why, because 4-7 cfm is wrong. None of the die grinders I have used are really that low and I had a sanborn compressor that was about 11 cfm. It takes a real 5hp compressor with 17 to 20 cfm to run die grinders non stop.

Yes, they do care how many stages you have as they need 90 psi while running. Unless you have a huge pump and the pressure switch set above 90 psi, a low pressure unit will run low on pressure at the tool. It is called headroom. Single stage pumps may not turn on until 90 psi at the tank. Mine is never below 135 psi, so it can make up for any losses due to restrictions, filters, etc. In theory, an average single stage may work and might be ok in some cases, but it isn't ideal.

There are calculators to figure out cfm based on fill time. My 5hp unit (Westinghouse air brake company 2 stage pressure lubricated, 213t 5hp baldor 1-3/8 shaft 1800 rpm, 27 amp draw on 240v single phase, pump is rated for 250 psi as well) fills 80 gallons 0 to 170 psi in 5 minutes or so and 1 minute to cycle 135 to 170 psi. It keeps up and averages 20 cfm as the pulley is a hair bigger than needed for rated rpm.

Somewhere there is an explanation on how they calculate cfm required for air tools and it is similar to old over inflated horsepower numbers. There are tons of threads on this topic, on this forum.

 

[carlaisle]

We know what your compressor is supposed to be putting out. What's the rated CFM consumption on your die grinder and the actual CFM you're seeing from the compressor? My IR die grinders both run about 11 CFM and my compressor's run time says that's spot on. I'm sure there are die grinders with higher and lower consumption rates than my sample size of 2.

 

[finn]

The math is wrong! Why, because 4-7 cfm is wrong. None of the die grinders I have used are really that low and I had a sanborn compressor that was about 11 cfm. It takes a real 5hp compressor with 17 to 20 cfm to run die grinders non stop.

Yes, they do care how many stages you have as they need 90 psi while running. Unless you have a huge pump and the pressure switch set above 90 psi, a low pressure unit will run low on pressure at the tool. It is called headroom. Single stage pumps may not turn on until 90 psi at the tank. Mine is never below 135 psi, so it can make up for any losses due to restrictions, filters, etc. In theory, an average single stage may work and might be ok in some cases, but it isn't ideal.

There are calculators to figure out cfm based on fill time. My 5hp unit (Westinghouse air brake company 2 stage pressure lubricated, 213t 5hp baldor 1-3/8 shaft 1800 rpm, 27 amp draw on 240v single phase, pump is rated for 250 psi as well) fills 80 gallons 0 to 170 psi in 5 minutes or so and 1 minute to cycle 135 to 170 psi. It keeps up and averages 20 cfm as the pulley is a hair bigger than needed for rated rpm.

Somewhere there is an explanation on how they calculate cfm required for air tools and it is similar to old over inflated horsepower numbers. There are tons of threads on this topic, on this forum.

Ok, I did some more checking.

There are two CFM ratings for die grinders as listed in the manufacturer’s specification sheets.

The first is average CFM for 15 seconds of operation at 90 psi inlet pressure.

The second is Full Load air consumption.

Some list one, others list the other, and several list both.

Those that list both show double to triple the full load air consumption over the fifteen second rating.

For example a CP 873 is 10/26 cfm, and a CP373 is 5.5/22cfm. You sometimes have to dig a little to get both numbers, and, like I said, not every manufacturer lists both on a simple search.

Others (I randomly selected 8) are an IR at 3, which would likely be a 15 second reading, to 28 for, I think a souix, which would likely be a full load number, although it wasn’t identified as such.

So yes, a 10 cfm compressor won’t keep up.

 

[nadogail]

Low prices and high output are mutually exclusive.

 

[PoorUB]

I did the math, and yes, it is slooow!

Something isn't right, like the others have said, perhaps the reed valves are dirty, or one might be broken. time to pull the head apart.

 

[The Cobbler]

time to pull the head apart.

could be as simple as a leak in the discharge line from the compressor head to the tank check valve ... been there done that

 

[MacMcMacmac]

You are getting about 6 to 7 cfm according to my calculations.

 

[mikedodge]

My 60 gallon 11 something cfm compressor has no problem with those mini die grinders, at least nothing that makes them unusable. I'm not sure how long it takes to air up, never timed it. It does take a while obviously if you're running tools at the same time.

 

[kabic]

Thanks for the info guys. It's a pretty cheap die grinder from Amazon...it claims:

Free Speed: 2,000 Rated R.P.M.
Recommended Air Pressure: 90 PSI.
Air consumption: 2.8 CFM, 80L/min.
Power: 0.6HP

I guess i will be taking the head apart and to clean it up.

 

[BurtEggley]

check the filter. One of the compressors I bought 15 years ago was barely putting out air. It just needed a new air filter. The reeds were carboned from the heat of running and running in those conditions. Replaced reeds on GP and put in a new filter. Great compressor.

 

[kabic]

I finally got around to taking my compressor ahead apart. Besides having a dirty filter it's broke (reed valve?)



There is also some metal flakes by the pistons. Im going to replace the pump.

 

[kabic]

New 3 cylinder compressor pump, new true 5HP motor. Empty to 130 in 4 minutes....that is an improvement

 

[kabic]

For your viewing pleasure

 

[The Cobbler]

I've got most all the parts to build a true 5HP v-4 jenny compressor . I need to get onto that project/
I have all the big parts ... 60 gal tank, motor, pump , mag switch , pressure switch etc. all I will need is belts ( if I don;t have some in my stash already) , belt guard ( have the mesh just need to fab it up) plumbing that I likely have etc.