vac advance should cum from a hole in carby that lines up with butterfly just of idle( vac advance when cruz, low load only)
advance off manifold,vac advance at idle/ to mutch advance!
tommo

Thats the one, the brass dick, best description ever.

Your economy will be bad because its not advancing enough through the revs without the vac advance.


Here a pic where the hose goes.

The port for vuc advance is inline with the throttle plate. Remember that the butterfly is eliptical shape and not circular and when the throttle is closed the butterfly sits at an angle and not "square" to the bore The vucuum is only applied when the throttle plates moves off the closed position.

If yours is not hooked up yet Pepper, this could explain some of your engine problems you have been experiencing.

if you dont have the vac advance connected it doesnt really do anything mines not connected webbers and dellortos dont have it
and i havent been running it for quite a while seems to be just fine

yeah benny, i didnt even see that port until just then, it was running a bit sluggy on the hiway today. hopefully its something as stupid as that after all the points-ig lead-dizzy cap gasket replacing ive been doing.

Quote:

Vacuum advance in standard distributors is worth about 10

Vucuum advance does heaps. Dont compare webers /dellortoes to SU /hitachies. The SU's type carb works solely on the vucuum created on the engine side of the throttle plate in order to operate. Webers and Dellortoes have the "accelerator pump circuit to counteract the rush of air when the throttle plates is opened.

Typically the static timing is advanced when Weber /dellortoes carbs are fitted..

Also if pepper has not blocked off the vacuum port on the front hitachi then that carb will see a vucumm leak. If the leak is present then the air rushing over the bridge, where the jet sits will be reduced. This condition will induce a lean mixture condition. The twin carbs will be out of balance also.

mines an elecy dizzy from something it wasnt connected when i got the car it was running really bad when i got it due to someone plugging in the spark plug leads in the wrong order ended up fixing it to the order it should be but then wouldnt run so did a full 180deg turn and the motor fired up beutifully and i left it like that till the rear carb #### itself now im losing fuel at the rate of about a litre a minute but i havent had the vac advance contected but still runs fine

Whoops!

As far as I can remember the difference between the std dizzy and a GX spec dizzy is the return springs on the mechanical advance. it was either, 1. the use of a single return spring from a A10 engine dizzy or 2. the use of only one return spring in an A12 dizzy. I will look it up and confirm..