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Installing Air Conditioning on Tii Engine


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Working as an ASE Certified Master Mechanic in the mid-1970s at a BMW dealership in Wisconsin, I installed Behr air conditioning (AC) systems in BMW 2002s. Recently I decided to install air conditioning in my restored 1976 BMW 2002. What follows are the methods, problems and solutions I encountered during the installation. I wrote this article for both the enthusiast and the professional. And I believe this is a very doable project for the enthusiast with little AC knowledge. If you are unfamiliar with AC terminology, secure some AC basic information and schematic before reading further.

Originally, I replaced the carbureted engine with an earlier tii fuel injected engine. On your 2002, the first thing I would check to see if the 3 mounting holes for the AC bracket are drilled and tapped. Some of the earlier engine blocks are not threaded. I had to drill and tap the ones on my engine which is cast iron and required a 90 degree 3/8th drill. They are located on the right (passenger’s side) front of the engine block. The fourth mounting hole is an existing motor mount bolt. Before you buy anything else, secure an original tii air conditioning crank pulley. On the tii, the AC drive/crank pulley is internal (photograph 1).  They occasionally become available on EBay and cost between $175 and $200. I bought a Sanden compressor, aluminum AC compressor bracket, condenser, electric fan and electric fan bracket from BLUNTTECH and the evaporator and system components from Dtechparts.

 I ran into clearance problems trying to adapt the Dtechparts compressor bracket plate (used with an additional drive pulley) on this tii engine. Dtechparts may have an additional solution for other tiis, but I spent quite a bit of time unsuccessfully trying to make it work. In addition don't buy, like I did, an AC hose/fitting kit over the internet. They are usually packed with all the weird fittings that are hardly ever used. I ended up having to buy most of the fittings I needed. The AC hose and fittings can be purchased at a local radiator shop or an auto parts store having a press to clamp the fittings and hoses together. Purchase the appropriate size (1/2, 13/32 and 5/16) hose lengths and O rings, a small can of compressor oil to lube the o rings, two each 90 degree fittings for the evaporator and compressor (with charging ports) and two each straight fittings for the condenser and dryer. A Gates # 6832 (green) drive belt fits the compressor,

To begin, remove the two front grills and kidney nose piece. Then unscrew the radiator bolts and remove hose clamps and hoses at the engine.  Take out the radiator.  Remove the four bolts attaching the fan to the water pump, four bolts holding the crankshaft drive pulley and the bolts holding the two plastic covers on the front of the Kugelfischer fuel injection housing. On the upper drive gear for the fuel pump there is a mark on the gear. Align this mark with the mark found on the upper part of the pump housing which can be seen looking down from the top side of the car (photograph 2). Turn engine until the two marks are aligned. Using a 1/2 drive 30mm thin wall socket remove the crank pulley nut. If an impact wrench is unavailable and the engine turns when you try to break the nut loose, place a breaker bar or large ratchet, with the socket attached to the crankshaft nut secure on the left side of the frame structure. Then use the ignition switch crank the engine over and the nut will come loose. Remember the engine turns clockwise. Realign the two fuel pump marks and remove the nylon fuel pump drive belt. It usually comes off fairly easily. The belt is usually a little loose but if it feels too sloppy replace it $70. Next remove the stock tii crank pulley drive gear. I was able to just pull it off by hand.  Check if the bolts that hold the alternator/fan drive pulley to the new AC tii crank drive gear sprocket are short enough so as not to interfere with the fuel pump drive belt. Next install the new crank drive gear sprocket making sure the crankshaft key and keyway are aligned. 

Secure the compressor bracket to the engine block (there is a supplied spacer that goes under the front lower bolt bracket) and then bolt the compressor to the bracket. The (large) oil fill compressor access plug should be located around 11 oclock and the two through bolts with spacers immediately inward on top (photograph 3). The two adjuster arms bolts go through the inner bottom of the bracket with moveable adjuster sides attached to the compressor (photograph 4). Install the v-belt and tighten the compressor. On the Sanden unit there is a ratcheting adjuster. If this gets hung up just use a pry bar for the tension adjustment and then tighten everything up. Eyeball the compressor drive belt to make sure it is aligned. Reinstall the nylon fuel pump drive belt.  For compressor drive belt clearance, cut two rectangular notches in the lower plastic cover and reinstall. Torque the crankshaft pulley nut to 80-85 ft lbs. Your AC compressor is now installed. Sanden AC pumps usually come from the factory with oil and do not need any additional. Check if this is not the case.

Install the electric fan as far forward and center and in front of all the braces. The electrical plug should be on the driver’s side. BLUNTTECH has a hold down bracket available, but I just made some brackets out of one inch bar stock and used some brass spacers available at most hardware stores (photograph 5). Similar brackets were made for the condenser (photograph 6). Install the condenser flush on top with a forward angle and make sure it will clear the radiator at the base (photograph 7). The large discharge hose fitting should be on top. with and then reassemble the rest of the earlier removed components.

Next drill two access holes to the condenser using a 1 inch and 1 1/8 inch hole-saws and buy two appropriate size rubber grommets (photograph 8). Install the new AC discharge hose from the compressor to the condenser. The hose ends connect to the smaller fitting on the compressor and to the larger fitting on top of the condenser. Lubricate the o rings and be careful to keep things clean. Use two wrenches to tighten the connections and don’t over tighten the fittings on the compressor or condenser. They are aluminum.

Next install the receiver/dryer with two clamps on the right side of the engine compartment (photograph 9). Screw in and tighten the binary safety switch. It has been suggested to attach the electric fan sensor wire to this switch instead of installing a new sensor in the engine coolant system which is very difficult to find the right sensor that fits and an access location. Attach AC line from the condenser to the receiver/dryer. Secure the AC lines from the compressor and the receiver/dryer to the evaporator. The same caution on tightening applies to these connections. Reinstall the radiator.  Other than attaching a few wires to the compressor and receiver/dryer the under-hood part of the AC installation is done.

There are several sources for evaporator kits and other under-the-dash components, so I will not address this portion of the installation. Also Dtechparts asked that there evaporator installation instructions not be duplicated. When you are finished have an AC shop evacuate and charge the system or purchase AC gauges, vacuum pump and refrigerant, then do it yourself. Safety glasses and gloves are required. Refrigerant can freeze your eyeballs.

 

Attach the hoses from the gauges to the low suction and high discharge ports. Open the gauges and then using a vacuum pump suction the system down for 45 minutes. Close the gauges and wait another 15  or 20 minutes. If the needles on the gauges havn't moved the system has no leaks. Attach a refrigerant can to the center hose. Open the low side gauge and hold the refrigerant can upside down. The can will get cold and then warm when it is near empty. You can also tell by the weight. Close the gauge and attach a second refrigerant can. Open the low side and start the engine with the compressor on.  Also turn on the cooling fan to max and put a thermometer in the AC outlet in the dash. The compressor will siphon in the second can of refrigerant.   A glass sight gauge is on top of the receiver/dryer.  When bubbles are no longer present the system is charged. Close and remove the AC gauge hoses. Check the thermometer in the outlet vent. It should read around 55 degrees. Fini

 

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Hey Thomas,

Nice work! Thats a sturdy bracket.

I see you've got a 400mm mech fan - whats your electric fan?

That SD5 creates quite a lot of engine load - is your idle OK when the compressor engages?

 

I did a single serpentine belt drive approach for an '02 turbo, because that tii-style compressor position & belt drive solution isnt compatible with the turbo engine...it would also work on a tii.

 

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Hello, I used a 12 inch High Performance SPAL electric fan for the conversion. As far as engine load at idle, I don't know yet because I procrastinated and wrote the above article instead of finishing the project. Your installation is a very clever solution to the clearance problems and way beyond my pea brain. Tom

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