Time to sort the dizzy and ignition but I'm confused and need help.

What's the difference between vacuum and non-vacuum? In terms of application.

I've got a lumenition kit already fitted to the car, do I need a fancy dizzy if i'm going to ditch parts of it to fit the optronic gubbins.

How can you tell if a dizzy is worn out, I've got several used ones kicking around but wouldnt want to risk fitting one if it would have a detrimental effect.

Whats the best plugs n leads combo for medium tune crossflow on twin 40's.

Many thanks,

Dave

In simple option terms, if your going to run twin 40's then go for a non vaccuum ditributor, cos getting a decent vaccuum supply is next to impossible.

A vaccuum advance unit does what it says, it advances the ignition timing in relation the amount of vaccuum applied to it by engine speed/load/throttle. If you are using twin 40's then taking the supply off of one barrel will give you a severly fluctuating vaccuum supply at anything other than closed throttle. So you will need a distributor without a vaccuum unit.


Enjoy.

Hi Dave

My setup is similar. I needed a side entry cap to fit under the carbs. I modified a Bosch dizzy - took off the vacuum advance unit, locked that part of the baseplate and found a new side entry cap to fit by spending time at the motor factors on a quiet morning (Fiat strada super I think it was in the end). Standard mk2 escort xflow motorcraft dizzy has no side entry cap available I think so you need a Lucas or Bosch.

Depending on your cam you might also want to modify the distributor centrifugal advance mechanism to limit the total advance and give decent idle and progression without too much advance at the top end. Dave Andrews site gives good advice on that.

I'm told the Lumenition Optronic module is very tolerant of play in the distributor shaft. Timing and dwell are hardly affected even by a quite badly worn one (which would spoil the tune on a contact breaker system). I guess you still want the best one you can get with least perceptible waggle though. Haynes manual quotes standard shaft play tolerance limit for guidance perhaps?

cheers
Dave