The EGT gages are only used in full throttle static RPM situations. Where engine load is holding the RPM steady and no throttle movement is in use. If the throttle is retarded the gages will drop off the peak reading and tell you nothing. If the EGT gage probes are about 3" from the port face, you can get good data. For a cross reference at full throttle and for combustion data at other than full throttle then use a heated oxygen sensor. High EGT at lower throttle settings suggest excess fuel burning in the header.  Piston tops melt due to running at best power AND not cooling the oil. Piston bottoms are cooled by waste oil from the connecting rod bearings. Best power in both piston and rotary engines is about 50 degrees rich of peak EGT. This is also where piston tops get soft and apex seals start to bow out in the center. If you have been around racers or hot rodders, you have heard "It was runnin great just before it blew up" It was indeed. It had been "leaned out" by the local Genius tuner and for the first time ever was running at best power, 50 degrees rich of peak EGT.  

 

Spark plug heat range is the number one killer of rotary engines and close to number one in piston engines.  If you can buy it in any parts store, it probably isn't cold enough.

 

Lynn E. Hanover

 

Thanks for you input Tracy.

 

I haven't checked my mixture monitor under this condition yet. I'll check that next time I fly but I do notice that the EM2 indicates that the fuel flow, GPH, starts to be reduced as the MP decreases and the EGT increases. I have been told that I should try to avoid EGT's above 1550 degrees and definatelly not above 1600. In spite of these high temps upon decent I look for overheated spark plugs and damage piston top and don't see any indication of over heating. I really have to richen the mixture a lot to keep the EGT under control so the question is am I just adding more fuel where it is not needed when I'm reducing power.

I have been meaning to use the auto mixture feature in the EM2 to fix this but I'm not sure it is necessary. Maybe I should just adjust the mixture so it at leased stays below 1600 degrees.

Does this sound reasonable.

 

Robert Bollinger

EC2 EM2 works great.

In Ford V6