by Jim "Ack" Cambron
It's been a couple of years since the original version of this article was written, so it's time to freshen it up a bit and fix some mistakes.
You can convert your Samurai Air conditioning Compressor for use as an air compressor. t does not cost much to do and is a fairly simple project. These instructions can also be used to build similar compressor systems for other vehicles.
You should consider doing this project if you have a need for air to inflate tires after off-roading, ou are installing Air lockers or you want to inflate air mattresses or other inflatable items. If you add a one-way pressure switch and a tank, you could also operate small air-powered tools to a limited degree.You should NOT consider doing this project if you plan to add power steering or you like air conditioning on your Samurai!
Although they are optional, you should consider including a pressure switch (to prevent over-pressurizing the system) a one-way valve and a tank. These items add to the over-all safety and versatility of the system. See the Operations section at the end of this documents fro details.
Part Description source Cost (2001 Dollars) ------------------------------------------------------------------------------------- Samurai A/C Compressor junkyard/vehicle ?? Outlet Connectors from A/C Compressor assembly junkyard/vehicle ?? 2-3/8" - 7/8" hose clamps hardware store $1.38 1-25' air hose with NPT nipples hardware store $10.00 2- barb hose connectors 1/4" NPT hardware store $1.86 1- 90-degree brass fitting 1/4" NPT hardware store $2.25 1- 1/4" NPT Brass tee hardware store $2.89 2- female snap air fitting couplers hardware store $2.19 1- male snap air fitting coupler hardware store $1.06 1- 1/4" NPT hex nipple hardware store $1.33 1- 125 PSI ASME coded pop-off safety valve 1/" male NPT hardware store $9.98 1-automatic line oiler 1/4" manle NPT hardware store $18.99 1- roll Teflon plumber's tape hardware store $0.59 1- 12V Illuminated toggle switch (Radio Shack 25-50706 or similar) Auto Supply Store $2.79 Tank Items: 1- compressor gage (0 to 150 PSI hardware store 14.89 2- 1/4" NPT Brass Tee hardware store $2.89 1 1/4" NPT one-way valve hardware store $ 1- 25' length of air hose with 1/4" NPT nipples hardware store $10.00 1- adjustable pressure release switch, 0-150 PSI hardware store $48.00
Refer to Figure 1 for parts placement. Be sure to wrap all threads with Teflon tape (or similar sealing product) as you assemble the plumbing. Note that the outlet connector on the compressor is the one CLOSEST TO the engine block and the inlet connector is the one that is farthest away from the engine block.
I used hose clamps and the original compressor hoses to simplify adapting the air plumbing from Metric (the compressor inlet/outlet threads) to English. Re-using the existing hose fittings is far cheaper and creates a better, professional-looking assembly. It also makes the task of compressor replacement a lot easier.
The 125 pound pressure relief valve (item 6 in Figure 1) is designed to keep from over-pressurizing the system. For safety's sake Carefully monitor the pressure on the tank's gage (if equipped- and it should be!) to prevent it from exploding because of over-pressurization! This is especially important when reinflating tires! Always monitor you tire pressure at too much pressure can cause violent tire failures resulting in serious injury or death!
If you plan on using the basic design to fill an auxillary air tank, try the design in Figure 2. You will also need the adapter pictured in Figure 2 on the right. The double-ended male connector allow you to connect the air tank (see Figure 2) for filling through the air hose. Although the female snap connector self-seals when disconected, a valve will keep the coupling from exploding apart causing potentially serious injury! Be sure to add a valve to your portable tank!
If you want to add a permanent tank to your basic compressor, use the schematic in figure 3. It uses a pressure switch that is designed to automatically shut off the compressor when a maximum pressure is reached - usually no more than 125 pounds - and turn the compressor back on when the pressure in the tank drops to a minimum level - usually around 60- 80 pounds. This system MUST use a pressure switch in order to operate safely avoiding potentially dangerous component failures caused by overpressurization.
Figure 4 shows a one-way valve installed at the output of the compressor. This valve will stop backpressure on the compresor from the system while it is not running. It is not absolutely necessary, but it can reduce unnecessary loading on the compressor and possibly prevent system pressure loss through the compressor.
Picture 1 is an example of how the compressor and plumbing is installed on my Samurai. You can place your air hose connector and tank wherever you want on the vehicle body. Just be sure that you keep the lines away from heat and the potential for damage from objects while on the trail. Picture 2 shows how I mounted the power switch (the red switch next to the dimmer control) on my dash.
Installing the basic system in my Samurai without a pressure switch and a permanent tank requires two people for safe operation - one to operate the engine throttle and compressor on/off switch and another to inflate the tire or other item.
Here is a suggested procedure:
1. Make sure that the compressor switch is turned off.
2. Pull up on the pressure relief valve ring to depressureize the output side of the compressor.
3. Connect the air hose and approprite tool (usually a tire inflating chuck) to the compressor output.
4. Start the engine and idle up to around 2000 RPM.
5. Connect the air hose to the item to be inflated.
6. Start the compressor to inflate the tire/item.
7. Release the throttle, turn off the compressor and check the air pressure on the tire/item as needed.
8. Turn off the compressor when properly inflated.
If you have installed a pressure switch and a permanent tank, you only need one person to operate the system which will operate like a typical shop compressor.
Here is what you do:
1. Start the engine.
2. Turn on the compressor and let the pressure build up until the pressure switch shuts off the compressor.
3. Inflate the tire/item
4. Turn off the compressor when done.
This system will inflate tires, air mattresses and other items quite nicely. It does not have the capacity to run air tools and is not recommended for that purpose.
There you have it. Have fun and be safe on the trails!