"Detonation" is the spontaneous ignition of the fuel air mixture. This occurs after the planned ignition event and usually at a location remote from the spark plugs. So, mixture temperature is usually to blame. So, the use of intake air coolers and intercoolers on super charged and or turbo charged engines. In order to reduce intake air temperatures. Also, additional fuel my be added to help reduce charge temperature.Also, lower compression rotors or pistons may be used.  Also ignition advance may be pulled out as boost is going up. Flame front speed is largely a function of cylinder pressure.
So, the higher the cylinder pressure, the faster the burn, and less advance is needed to get best cylinder pressure near 50 degrees after TDC. Ceramic seals hold up well to detonation. Steel seals and carbon seals do not.

"Preignition", is an ignition event that occurs before the planned ignition event. Unlike detonation, it often occurs at or near the spark plugs. Usually too high a heat range (plug tip overheats and becomes a glow plug). Running the ideal mixture for best power is very popular. However with best power comes highest cylinder temperatures and the least amount of cooling oil. When leaning to lean of peak operation, move quickly through ideal and get to lean. The more powerful the ignition system the leaner it will run without missing. Faulty distributor cap, plug wires too close together. Primary wires not shielded from secondary wires. Solid conductor secondary wire (Use inductive secondary wires in most cases).

You can induce both problems at one time.

One outstanding feature of the ceramic and the carbon seals is that they weight nothing compared to steel seals.So, they will track the chrome well up into stupid RPM. For above stupid RPM, multiple springs can be installed with still no chrome damage.  Also there is just a one piece seal, so no pesky corner piece to overload one iron face. Carbon and ceramic seals must be fitted to each housing using a diamond file. Check with supplier for specs.
With both carbon and ceramic seals after years of racing show no wear at all on chrome faces. Ceramic seals stay as new and carbons last about 2 years.

Lynn E. Hanover


This is a piston engine Lynn. What is the source for this definition.

I would say for an aircraft engine the extra cost of Iannetti apex seals is essential.
For turbo charged Mazda Wankel the iron seals are marginal.
Steels seal are not to be used if you expect your engine to last.


Paul Lamar

   The Rotary Engine free News Letter. Powered by Linux. If you want off
   the list PLEASE let me know and I will remove  you.  ACRE NL web
   site. http://www.rotaryeng.net You Tube http://tinyurl.com/beqqxas
   Copyright 1998-2017 All world wide rights reserved.