Originally Posted by Jobro

For cutting opposing teeth, this is what I did.

Pull cover off the CAS.

Turn engine to 5ATDC (-5BTDC), ie where the First timing mark is on a factory pulley.
Allign CAS in centre of adjustment, then rotate it slightly counterclockwise, push CAS into engine without holding the wheel steady.

Pay particular attention to how pushing the CAS into the drive teeth, turns CAS, it will turn 2 more teeth, and end up in dead centre of adjustment again. This is exactly what you want. The tooth, current on or closest to the Ne sensor is the 5ATDC tooth now, if you do this.

Count back one tooth(in counter clockwise direction), if that tooth was -5ATDC, now you are on 25BTDC, count back another, now you are on 55BTDC, count back one more tooth. This is the tooth to cut.

Mark to tooth to chop with black Nikko pen (permanent marker, bearing blue, nail polish/ whiteout you guys might call that liquid paper). Remove that tooth, and the one completely opposite to it.

You will need to strip down the CAS to remove the 2 teeth.

Get a punch/nail and hammer on the pin holding the gear on the bottom of the CAS off. Remove the 4 screws holding the sensors inside the CAS body. remove the sensors and be very gentle with them. Take the one that was for the 2 tooth wheel and store it in a safe place (good working backup incase you fudge up the other one).

Remove the other 2 screws holding the shaft/bearing assembly in, push shaft out, then remove the teeth. Reassemble in reverse. leaving out 2 tooth vr sensor.

I'll explain the trigger settings for you.

Because the missing tooth is on the 85BTDC, the tooth count is reset here. The next tooth passes the sensor, and the MS adds 1 to the reset tooth count.

you can see you are on 55BTDC when this happens. The trigger settings are usually 1 3 7 9 for missing tooth setup on 12-1 wheel.

So the ignition timing starts, and the ECU just does a delay to retard the timing back to where you want it.

As the engine keeps turning the 2nd tooth passes the Ne VR sensor, count=2.

Turns more, 3rd tooth passes the VR sensor. count=3.

Because you setup the timing to use crank based timing, tooth 3 passing the VR sensor tells the ECU to fire here for cranking timing, you see this will result in a cranking spark advance of -5BTDC or 5ATDC.

As soon as the engine rpm gets above the cranking rpm value the timing changes over to using the 1st tooth trigger and the appropriate delays.

The teeth 7 and 9 are just the same as teeth 1 and 3 only 6 teeth away, ie 6x30degrees = 180degrees out of phase. Which is exactly how much the front and rear rotors are!

Hopefully that makes a bit more sense for you!