There are a number of methods used to blow the coolant out of a Mazda engine. The most popular is actually overheating the engine by not removing every spec of air from the cooling system. Many bubbles form in the top of the cooling jacket. They do not move unless the engine RPM produces ample coolant velocity.

As in a take off or taxi test. Then they form up un front of the high mounted water pump and cavitate the pump to a standstill. Seconds later there is no coolant to be found. Drill a hole in the top of the center iron and install a bleed valve. Can be a Shrader valve with a metal cap. This to leave open while filling with coolant so as to let said air out of the very top of the engine. 

 

Coolant means distilled water. 10% glycol. One teaspoonful of Dawn dishwashing soap or Redline Water wetter per bottle instructions. A bottle of Barsleak. Yes that brown water with the Rat poop in it. If it is good enough for a $100,000.00 Cosworth V-8, then its good enough for a Mazda.  A 22 pound Stant pressure cap and a recovery bottle so you can see where the fluids went.

 

Note that the rotor housings act as though they are made of hard rubber. If one is only slightly warped it goes flat when the stack is torqued up. No problem. If a iron is warped it is scrap. You can lap facing surfaces of Irons against each other. This where minimal wear has been observed. For heavy wear you can

have an automotive shop take off a few thousandths, then lap the piece against its partner to remove most tooling marks. You can also do a great job with a cleaning tank using kerosene and an air powered random orbital sander. Glue on some 320 wet or dry paper and sand the wear surface under a stream of Kerosene.

The little circles are great for holding oil. Once clean check for cracks.     

 

And now into the weeds.......Many schemes have been tried in the pollution control area. Most involve exhaust gasses being loose inside the rotor housings where compressed air from an air pump was fed into the exhaust stream through two steel nozzles that project into the exhaust port. This air came from a port in the center iron that is covered by the intake manifold. (In most every case). Those nozzles must be plugged.

The supply port in the center iron must be covered. The nozzles do not fit tight and may leak fresh air into the exhaust stream and supply a cracking and popping sound that confuses the tuner and Oxygen sensor.

 

The center iron should match the coolant openings pattern of both rotor housings. On assembly add a thin coating of GE 100% silicone tub and tile sealant to the faces of the land areas that hold the "O" rings. Works great to cure the tiny leaks and be sure to put it on the down legs clear to the pan rail to keep oil from seeping out when hot. I use the same GE silicone to seal the exhaust flanges to the engine. Stays leak free until you pry off the exhaust system for service. If there is no gasket, it cannot fail. I have used a copy of the RX-2 RX-3 cooling system since 1980 Never an overheated engine. I can publish that drawing if anyone wants it.

 

Set the side seal end clearance to zero, not .002" to 004" as seen in some books. If both side seals and the gives you as close to advertised compression as is possible. Quick starts even when hot. If the side seals and the corner seal pop back up after being compressed, then it is perfect. Good to 9,600 RPM.

 

More on bullet proof Rotaries as soon as I remember it.......The last racer is available and the spare (250 HP) engine is available.

 

Lynn E. Hanover

 

 

 

 

 

For the first time in the life of the plane I am considering throwing in the towel on the rotary engine concept, or at least my ability to manage it....

Hey Dave; 

   When I was building my plane, my buddy that helped with the test flying questioned my use of the rotary but by the time we finished the test flying he came to admire it (he really liked that it kept running even after we severely detonated it until after we got back on the ground), but a few years ago he chose to buy a flying BD4 with an O-360. He flew it once, before having to have the engine rebuilt. And FI update.  For $45K. And now 2 years later he's still only a couple of weeks away from flying again..... 

So don't give up, thinking the alternative will always be easy. 

But as for your current problem.  Ever hear of a dye kit? I've got one and only used it once but it was worth it. Add a pack of fluorescence dye powder to coolant. Run engine. Use black light type of flashlight and look for traces of bright dye. All included in kit.