Engine driven Compressed air for skoolies without air brakes

nat_ster

Senior Member
Joined
Aug 28, 2011
Posts
2,936
Location
Stony Plain Alberta Canada
When needing large volumes of high pressure compressed air, there are a few options.

12 volt.
Big money for little gain. IMO not up to the task enough to even write about.

120 volt
If you have a large enough inverter and battery system, or access to shore power, you can use a small garage style compressor. The cost for a small pancake compressor is around $100. Disadvantage is the compressors of this size will struggle, and may, or may not get the tire re inflated at 90 psi or more. You won't have enough to run air tools, or blow anything clean.

Mechanical
The york air conditioning compressor is a belt driven, 12 volt clutched, high displacement air compressor. Unlike the newer style screw compressors that rely on oil in the freon, the york has a internal oil reservoir. These factors combined with the light weight, and compact size make it highly favorable to generate large amounts of compressed air.
Light duty 4x4 users have been using the York air conditioning compressor to inflate tires, and run air tools for a few decades. While the light duty passenger vehicle market has turned away from the york, the MDT, HDT, and commercial and Ag market still use them. Most bus engines would have a factory bracket to install one under the hood. In some climates, they ran two side by side. CFM output is comparable to a $600 120 volt compressor.

Pic of a York with a V belt clutch, a small air filter, and a hose quick coupler on the out put port.


This York lives beside a air conditioning compressor that's still in use.



This York is running off a combo pulley on a alternator.


Diagram of how to hook it all up. Some parts in this diagram are not needed for a basic system.



A York with a V belt pulley.




A York with a serpentine belt pulley.



Pic of a Combo pulley to adapt a serpentine belt system to run a V belt York.



Installed.



I may edit this as time go's on.

Nat
 
Re: Engine driven Compressed air for skoolies without air br

One of the images shows the York with a quick-disconnect coupler right at the compressor. Does that mean it can be used without a storage tank? What is the max PSI and CFM for the compressor alone and are these two ratings dependent on the engine RPM or does the compressor have some kind of internal regulator to prevent damage to external systems? Thanks for the post!
 
Re: Engine driven Compressed air for skoolies without air br

PDBreske said:
One of the images shows the York with a quick-disconnect coupler right at the compressor. Does that mean it can be used without a storage tank? What is the max PSI and CFM for the compressor alone and are these two ratings dependent on the engine RPM or does the compressor have some kind of internal regulator to prevent damage to external systems? Thanks for the post!

A few Yorks had a blow off safety valve built into the side of the compressor. The quick coupler pic was likely just for testing purposes. I would not recommend running one without a small air tank, safety blow off valve set at 175 psi, and a $20 air compressor switch to operate the clutch.
With only a pressure switch, and no tank, the York will short cycle, reducing the clutches life span. Only a few gallon tank is needed, many jeep owners have used old fire extinguisher tanks.

I have used a York to reliably compress air to 250psi. They are capable of over 400 psi, but fittings, and tanks fail at such pressures.

The York 210 series compressor is the largest, and most desirable for compressed air generation. Large 10 cu. in. displacement fills tires fast. Rated at 4 CFM at 90 psi while running at 1200 rpm. Capable of 8+ CFM! Running air tools isn't a problem anymore with this on

I found the displacements of the different York/Techuseh compressors in an old JCW catalog a while ago. Here they are:

Model Displacement (cubic inch per rotation)
F206R 6
F210R 10
R209R 9
R210L 10
T210L 10

To decode:

first digit
F= flange top
R= roto lock
T= tube-O

2nd digit:
2= 2 cylinder There were a few larger 4 cylinder units, but they were cast iron, heavy, and not worth covering in this article.

3rd and 4th digits - cu.in displacement of air during one rotation

5th digit:

R= right hand suction
L= left hand suction

This assumes a Compressor Pulley of 5" diameter, and an engine pulley of 6" in diameter.

CFM=(CID*RPM)/(12*12*12)*(Drive_Pulley_Diameter/comp_pulley_diameter)

Compressor Cubic Inch Displacement Cubic Feet per Minute Output @ Engine RPM
1000 2000 3000 4000
6 4.17 8.33 12.5 16.67
8 5.56 11.11 16.67 22.22
9 6.25 12.5 18.75 25
10 6.94 13.89 20.83 27.78

York's have a max RPM of around 6000 RPM. This calculation places the output at almost 14 CFM at 2000 engine RPM. For a small gas engine that red lines at 7000 RPM direct driver would be best. However this is faster than we want to be tuning out bus diesel engines.
Even at 1000 RPM of the bus engine, the York will out put 7 CFM, the equivalent of a $400 construction compressor.

For more output without revving the bus engine ,this is where the combo pulleys can act as a overdrive.

Nat
 
Re: Engine driven Compressed air for skoolies without air br

Most of the older compressors ('60's & '70's) are threaded on the bottom and on opposite sides. Unfortunately, they will only self oil standing upright or laying on one side but not both. For side mounting, care must be taken that the oil slinger is in the correct position to work as it is reversible. Often you can tell which way the pump was mounted when it was in use but when it has been cleaned up it may require taking the pump apart to find out which way it was set up.
 
Re: Engine driven Compressed air for skoolies without air br

Thx for the info Ol Trunt. That's one small detail that could turn into a real big one fast if over looked and the York seizes up. :shock:

So with that info, we should try to reference the original mounting position of the York in it's donor vehicle when ever possible. That will save you some of the work that Ol Trunt mentioned.

Also folks, I urge you to search Google as well on this topic. There is much to sort through, learn and experiment with. This is a topic with lots of content throughout the internet. I just brought the basics here to get my fellow skoolies minds rolling.

One of my near future projects is a 12 valve VE pumped Cummins 5.9 out of my old 91 dodge truck. It will become a 6 York compressor, with a 27kw brush less generator combo.
It will get it's own build thread, but I will cross reference some of the pics here.

Nat
 
I think this is an excellent thread and will use my powers of persuasion to have it pinned.
 
The bus we just got had the air conditioning compressor go out and was removed prior to our purchase. This York compressor just does compressed air or can it do air conditioning as well? Maybe a silly question. Thank you for this thread.
 
"I" have one of these in a 26 Uhaul. The previous owner put an m style quick connect on it so I'm good to go!

So I guess, besides busses, old Uhaul trucks are a good place to look for these.
They are used to run air bags that raise and lower the floor.
I don't have air breaks, so I'm temped to install one of these for onboard air.
My positive pressure water system might just be a reality....
 

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