| The Cooling System |
 |
THE OIL SYSTEM Rotaries need big oil coolers. If you happen to have the 84/85 oil cooler, toss it in the trash. These are a water/oil cooler and don't work worth beans. Not only are they ineffecient at cooling the oil, but they leak oil around all the gaskets and look ugly. Insead get a 83 and earlier oil filter mount, and put an external oil cooler on it. I have two 72 plate mesa style oil coolers on the car now. I have a temp gauge on it and I have never seen it read over 160 degrees! I think I went overkill a little bit... THE WATER SYSTEM The radiator is out of an 81/82 Mazda RX-7. This is a 3 core copper radiator that fits in the spare tire well very nicely. I have also seen successful conversions using a VW Jetta radiator, which is a little smaller, and is made out of aluminum (which is a little more efficient than brass). The coolent tubing is 1.5 inch (38mm) copper tubing that is all soldered together, with an air bleed at the highest point of the system. I ran both coolent lines undernieth the car running pretty much under the drivers-side running board. Even with my car being lowered, I have not scraped the coolent lines on anything, so you shouldn't worry about that at all.(unless you are really low, in which case you are going to need to do something creative!) NOTE: Since the cooling system is so long, the water pump and system get "shocked" when the thermostat opens. Basically when the engine is cold, the thermostate keeps the radiator fluid from flowing throught the coolent system. When the engine reaches a certain temperature, the thermostat opens and the coolent starts to flow. I noticed that with my 180 degree thermostat, the temp would get to about 210 degress before going back down to 160, at which time the thermostate closes again and the process repeats itself. I realized that when the themostat opened, it would have to push all that fluid from a stop to moving. This stresses the cooling system and the waterpump. SOLUTION: I drilled out the thermostate with a 1/4 inch (6.35mm) hole. What this does is gets the fluid moving slowly until the engine heats up enough to open the thermostat. This creates less shock to the waterpump and the cooling system because the fluid is already moving. This effectively solved my temperature bouncing problem. Here are some of the specifics of my car. Here is how everything went together in the spare tire well, don't be afraid to cut into your car! I mounted the radiator backwards in the car. This means that the radiator outlets come out the front of the radiator, on the drivers side. I then soldered 90 degree bends on the radiator to make the outlets go toward the side of the car, where rubber lines connect to the copper coolent lines. Once you gut the spare tire well, you are going to have to support it somehow. After all the cutting, the front of your car wil become very flexible. I welded supports to tie everything together while still leaving enough room for ample airflow. To get the radiator in the car, I found the easiest way is to make a radiator frame built around your radiator, then weld that from into your car. Here is how I did it: 1. Get yourself the biggest radiator that will fit, 81/82 RX-7 Radiator in my case 2. Get some 1/2 inch square steel tubing (pictures coming) 3. Weld up a rectangular frame to seal against the face of the radiator (pictures coming) 4. Weld up the brakets to mount the radiator to the frame (pictures coming) 5. Mount the Raditor to the frame (pictures coming) 6. Get all the bracketry figured out for the electric fans 7. Remove fans and radiator and weld the frame into your car. Pictures below |
 |
 |
 |
 |
 |
 |
| Next step, radiator tubes. The radiator tubes were ran undernieth the car on the drivers side. I used 1.5 inch copper tubing and used some pre-made 45 and 90 degree bends to get everything together. The whole tubing system is copper pipe except for where the tubes go into the engine and radiator. I used copper becuase it does not corrode, but according to Kennedy adapters, you can use galvanized steel as well (such as electrical conduit) . Tie the engine to the radiator. Make sure that the highest point in the water system is either you water filler (radiator cap) or an air bleed. Since most cars use copper/brass radiators, antifreeze selection is easy. There are specialty antifreezes that will corrode copper (such as those used by new cars with aluminum engines with aluminum radiators) but any general antifreeze will work. You should not use Stainless steel for cooling tubes unless you run the tubes inside the car/inside the heater channels/ or inside the tunnel. Stainless does not conduct heat very well, so you will not have the cooling benifit of running such a long length of tubing. If you run the tubing inside the car, stainless is the best because it will not conduct as much heat inside the car. |