In a message dated 1/26/2009 7:20:31 A.M. Pacific Standard Time, wgeslick@gmail.com writes: I sure hope somebody comes up with an explanation for coolant in the rotor housings, as I can't find one! I tore down my engine because of that, and could find NO o-ring leaks. If it leaked, it didn't leave any evidence. The system would hold 15 psi pressure for a week or so, but would slowly leak into the rotor housing. Up to temp, it would blow air into the coolant system (equal opportunity leak).
Didn't find the coolant leak, but did find about 3/4" of one of the side seals missing. Now I am gathering parts to put it back with '91 rotors (need a rear counterweight), and looking at street porting. Does anyone know if there is value in street porting if 6000 rpm is the highest you will see? Lynn??
Bill Eslick
Yes the airplane application begs for a port job. Constant RPM. Long runs. A good choice of inlet lengths.
I would not early open enough to drop the trailing end of the side seal. And no more than maybe 65 degrees ATDC closing. Radius all edges of the port so no wear problems.
I have yet to use an aftermarket water or compression seal of any kind in an engine. A friend let his racer sit all winter and it froze up solid and pushed out a core support plug. The older guys call them freeze plugs but that's just what they do sometimes. He then got it running a week before the new owners were to arrive from Florida to pick up their new racer. Of course it only ran long enough to seize the bearings because of water in the oil. So he called me..........We took it down in 30 minutes. Permatexed the freeze plug (core support plug) and pressed it back in. On Cosworths you drill and tap 6-32 holes beside the plugs and add a washer to the socket screw so the plug cannot fall out, no matter what. Then you safety the screw heads together.
So we had it all ready to go except for no new seals. I added a really small bead of 100% GE silicone sealant (tub and tile caulk) to the bottom of the grooves. Installed the old seals and assembled the engine.
I add that silicone even on new seals.
If you can have the engine at an angle rather than straight up on assembly, you can do that center iron trick by yourself without dropping anything.
I reused seals for years before other people started paying me to use new stuff. Anyway. There is a method to torqing the cases. You notice that if you keep checking all afternoon the torque on one or two bolts still keep moving after three complete torque cycles. I use the lowest figure for whatever year engine, but use anti-seize in the threads, silicone on the bolt centers, and anti-seize under the bolt heads and washers.
Torque up by the book. Do it again in 6 hours. Do it again the next day. Now it will stay torqued.
The engine went back into the car. Started easy. Went to Florida with the new owners. Won Saturday and Sunday at Sebring. New owners very happy. Jackalone brothers. Now running the number 26 GT-3 Porsche.
Finished 10th yesterday. I don't know where the Mazda went. Never got any calls on it.
I suspect that the lack of proper torque also helps induce the rare broken case bolt.
If you reuse the seal washers under the bolt heads, use silicone under the washer. The stack can leak water into the bolt hole but not anywhere else. That is why the washers have "O" rings on them.
Torqueing the case bolts will often cure a water leak. That microscopic bead in the "O" ring groove prevents leaks. You add some to the legs but then dream up rules about why it is a bad idea anywhere else.
The cases with the groove in the iron will not survive a hydrauliced "O" ring. The iron will crack. So clamp a flat across the groove with the ring in it, to be sure there is space around the ring.
To be sure there is a bad enough problem to require a teardown, I would pressurize the block full of water to 50 or 60 PSI and listen to the exhaust ports. Sometimes you need to push those rings against the outside of the grooves to get a seal going. I would throw in a bottle of Barsleak and run it for a while. But some will feel that it is too ghastly a thing in an airplane engine. The irons and housings are very flexible, and a good torque job will pull them flat. Usually.
On the other hand, I would take it apart just to look at stuff. Leaking in a fresh engine is just so rare, that it screams look at me.
Heating: If it reads 200 degrees on the gage. It was hotter than 200 in there somewhere. If it reads 230, it was hotter than 230 in there somewhere. That 230 water is mixing with cooler water before the gage probe sees it. Notice that the plug side has more case bolts than the cold side.
Hot is very bad mojo. Overheat can cause the plug side of a housing to be shortened a bit.Then not seal worth a damn when reheated. It is very difficult to get the air out of the engine.
Hold your hand on the water outlet to the radiator when the engine starts. You should sense warmth in the aluminum within one minute at fast idle. Otherwise the water pump is not moving coolant.
It is just too easy to build one of these things back up to take a chance. Take it apart and see what went wrong. Too much money has been invested to poke around with this and that. Tear it down.
Lynn E. Hanover
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