Trigger Wheel Positioning

[Dazman1360]

Hi all,

First post, so apologies if my questions is a little stupid!

I'm rebuilding a spare engine for my Triumph Herald 13/60 and at some point in the future I want to add Megajolt. In preparation I have purchased a trigger wheel to mount at the rear on the crank pulley so this can be in place in when the engine goes back together.

My question is about where to have the missing tooth in relation to TDC. There's a very good article here about fitting to a Spitfire engine which is the same basic engine design as mine, in this instance the missing tooth is centred on the TDC mark of the pulley and the sensor mounted 90­° anti clockwise.

Having the sensor 90° from TDC is a good location for the 4 cylinder Triumph engine, so I will probably fit here, so my slight confusion is why would you not have the missing tooth 90° offset on the pulley so the sensor is centred over it when the engine/pulley is at TDC. I may be missing something obvious but thought I'd ask the question before fitting mine.

Many thanks

[Swedge]

engine to tdc
fit the sensor at the easiest location
put the trigger wheel on with the missing tooth aligned with the sensor
turn the trigger wheel (not the crank) 9 teeth clockwise

[Dazman1360]

Thanks for the reply.

To confirm, just so I'm 100% sure I get it right. With the Pulley at TDC, the sensor (wherever it's mounted) should be 90° anti-clockwise of the missing tooth on the trigger wheel?

Cheers