When it comes to air demand on an air suspension, the quicker you can get the air, the more play time you'll have, and the more you can impress the ladies. 12volt compressors, while mostly reliable, are slow, and don't provide users with the playtime they sometimes want. Thats where engine driven compressors, or EDCs for short, come into play. With an EDC, you can have air on demand, that pumps almost faster than you can get rid of it. While the output of an EDC depends on the speed of the engine in rpms, even at idle, an EDC will output at least 4x the amount of air that a single 12volt compressor can output.  This tutorial will revolve around converting the popular York a/c compressors for use on late model v6 S-10, but can easily be adapated to other vehicles.

Converting a York A/C Compressor
The most popular conversion for engine driven units is done with the York a/c compressor, found on many early 80's Ford vehicles.  Essentially the compressor is converted from a freon based compressor to compressing air into a storage tank.  Currently, a company called Climate Control Inc (CCI) owns the York brand of compressors.  The York is an ideal compressor for use in these situations because it doesn't depend on the freon for lubrication.  Lubrication is done via the splash sump system inside the compressor.

Advantages of the York

• Cost - Between junkyards, ebay, used parts dealers and more, these compressors can easily be found for less than $50.  they can normally be had for around $25-$35.  They are most common on early 80's Fords, Volvos and Audis.
• Output - The cfm output of these compressors is fenominal compared to that of electric compressors, and because they don't have an electric duty cycle, they can run for much longer periods of time.
• Reliability - These compressors were made to last.  The one being used for this tutorial was manufactured in 1984, 22 years ago, and it still works as well as it did on day 1.  Properly maintained, they will last a long time under the hood of your vehicle, and should it need to be rebuilt, it is easy to do. 
  

The Conversion
To the right is a cutaway shot of what a standard York compressor looks like. Not a complicated compressor by any means. The most common model used in the Jeep circles is the E210 model. This is the full size York that has a 10 in³ displacement on each revolution. It can be found on many early 80's Ford pickups, Volvo's and BMW's. The compressor that I will be using here is the SC209. The SC means Super Compact, and the 209 represents the 9 in³ displacement on each revolution. I found this compressor on an early 80's Audi 4000s. It will have a v-belt pulley, but thats ok, thats what we want.

In order to make this conversion work, we have to have someway of connecting our compressor to our system. We have a few options here. The first is to obtain some fittings that will convert the existing ports to NPT ports. Kilby Enterprises is the one shot stop for just about anything you will need for your full size compressor. The second option is to cut off the factory tubing off of the donor car and simply clamp your hose onto the aluminum part of the cut off hose. The third option is to drill out the rear ports a tad larger, then tap them for 1/2" NPT. That is the option that I chose. In doing this, however, you will need to purchase a gasket kit from Napa. After drilling and tapping, there will be little pieces of aluminum all over the inside suction and discharge chambers that you will have to clean out by taking the head apart, thus needing a new gasket.

Getting The Parts
Unfortunately its not just as simple as installing the compressor and running some hoses. There are a few other components that play some important roles in the system. If you have an already existing air ride system, then the tank is out of the way, and one less thing to worry about. If not, you will need to get some sort of storage tank.  You'll also need an intake filter for the compressor, or someway of getting clean air to it. The air that leaves the compressor will be filled with oil, which needs to be removed by a coalescing filter. The amount of oil passed can be reduced, and that will be discussed on the following pages. After the filter, a check valve is needed to prevent air from your storage tanks from flowing back into your compressor.  If you don't have a pressure switch, you'll need one. A good one to use is made by Square D, and they come in a variety of flavors, from 90 PSI to 200 PSI maximums. You can read up on pressure switches at Beginner's Corner . You'll also want a gauge, relief valve, airlines.

What I Have

• Compressor - Acquired from the junkyard from a 1983 Audi 4000s.  The SC209 model has two cylinders, and has a 8.69 in³ displacement on each revolution.  At 1200 rpm's, it has a freeflow rate of 6.04 cfm, and at 90 psi, an estimated 2.91 cfm.
• Brackets - I bought some brackets from suicidedoors.com.  The brackets will bolt right up to the passenger side of the engine.  Kilby Enterprises may have a bracket that fits your vehicle.
• Tanks - Because of the already exisiting air ride system on my truck, I have two 5 gallon tanks.
• Filter - I had a small conical filter from autozone that I never used, so it will take its place here.
• Gauges - Due to the air ride system, I already had some gauges
• Pressure Switch - Again, already on the air ride.
• NPT Fittings - I've been working on air ride suspensions for over 4 years, and have accumulated a nice collection of fittings.
• Air Line - Plenty of this left over from my install on my truck two years ago.
• Alternator Pulley - Kilby Enterprises makes a replacement alternator pulley that has an extra groove on it for a v-belt to run the compressor with. He also makes an over drive pulley, that will spin the alternator, and thus compressor, faster at a given rpm.

What I Need

• Coalescing filter - The oil needs to be removed from the output air, so this is a definate necessity.
• Safety valve - Either a safety valve or a relief valve should be used. The output from these compressors is high, and fast, and if your pressure switch breaks, you could end up with a very very high pressure system that is very dangerous. A safety valve will eliminate that possibilty.
• Check valve - The air flowing to the tank needs to be prevented from going back into the compressor while its not running, and thats what the check valve does.
• Steel Braided air hose - The air coming out of the compressor will be very hot. Hot air, with high pressure will blow a regular nylon air hose. Steel braided is the way to go. A 4 foot length to the filter should be good.
  
• 30w Motor Oil - After talking with Brad Kilby of Kilby Enterprises, he recommends running straight 30 weight motor oil in the compressor, so this is what I'll buy.

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