RB26DETT Timing adjustment 

Checking ignition timing on an RB26DETT engine

  • On the back of the center spark plug cover is a timing loop. On the R34 its blue.
  • Connect timing light to loop. Direction of the loop is important. If the readings seem 40 degrees off, flip the loop over
    • If you still can't get a good reading, you can put a spark plug wire on cylinder #1 to get a reading
  • Disconnect IACV-AAC valve harness to cancel idle speed and ignition timing feedback controls
  • With engine idling check ignition timing.
  • Base timing is 20 deg BTDC
  • 0 is the orange mark on the factory damper. 30 is the last mark. The lines are every 5 deg.
  • Damper timing
  • If the timing needs to be adjusted. Loosen the three 10mm bolts on the cam/crank sensor.
    • Clockwise - Retards ignition timing
    • Counterclockwise - Advances ignition timing
  • 20 deg BTDC should be about in the center of the range of the cam/crank sensor with stock cam gears. If its at some extreme, you probably did something wrong.