The Death Rattle of a Wankel
   author unknown

   Rotary engines are simple and require no real special care, and they will last longer if you are easy on them.

   Loss of compression past seals is the main problem with high mileage rotaries. Typically, one apex seal fails causing low compression and hard starting. Because each rotor gives three distinct pulses for each ratation, low compression due to a bad apex seal is often heard as uneven cranking speed.

   Compression testing will show bad apex seals. While the special compression tester is best, a standard compression gage is still useful. Hold the release valve open while testing to observe the needle's free movement, and pay special attention to comparing the results from one rotor to the second. They should give equal readings. Remember that there are three pulses per rotor revolution.

   Two weak and and one bad pulse is a typical indication of a bad apex seal. Leaking side seals show as just one weak stroke and two strong ones.

   On 1993 and later, any vacuum reading below 18 inches of idle vacuum is reason to suspect the rotor seals.

   On all rotaries, smoking through the exhaust during deceleration shows the oil control rings are going bad. Also, early engines will blow exhaust into the cooling system when over heated, so check for bubbles in the radiator.

   Some rotary racers claim that the engines run better and go faster until they suddenly give up.