1st Gen Compression Checking Your Rotary Engine

How to Compression Check Your Rotary Engine​

Time Investment: ~30 minutes
Difficulty: Low

Tools Used:
Compression Tester
13/16 Spark Plug Socket

  • For this guide it is implied that you have a Rotary specific compression tester.
  • You can perform the compression test warm or cold, but for accurate results it's recommended to be warm.
  • You can use a normal piston compression tester, but must remove the Schrader valve (requires two people or a remote starter).
  • If using the piston compression tester method, each needle pulse (bounce) will be that faces PSI.

1. Start the car and let it warm up to operating temperature (~185f) before shutting it off.
2. Disable the vehicles ignition and fuel system
  • Remove the EGI (Electronic Gasoline Injection) fuse (pictured below is the FC location).
    • Remove the Fuel Pump fuse for Carbureted FBs and start the vehicle so it will suck in the remaining fuel in the bowl before dying.

  • For the FB chassis, remove the coil wires from the distributor
  • For the FC Chassis, unplug the CAS (Crank Angle Sensor)

  • For the FD Chassis, unplug the ignition coil connector located on the backside of the power steering pump.
3. Remove both trailing spark plugs from the engine

4. Input the compression tester sensor into the front spark plug hole

5. Connect the sensor to the compression tester and turn the tester on

6. With the gas pedal fully depressed, begin cranking the engine until the compression tester displays readings

7. Repeat for rear rotor housing
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