can someone make sense of this for me?
The trigger wheel should be mounted to the crank shaft front pulley. The missing tooth should pass the sensor when the engine is at 90* BTDC. It doesn’t need to be an exact 90*, as you will adjust the offset when calibrating the NODIZ. But aim for +/1 10* of accuracy here! Note that many engines, such as the Ford Zetec or Vauxhall C20XE Redtop, already have a suitable crank sensor and pulley arrangement built in, so you can utilise that if needed. If not, here is an example of a crank sensor and trigger wheel fitted to a Ford Pinto engine. This kit is available from us, as well are universal trigger wheels and crank sensors.
thanks