Hey all,

I asked a question on an old thread and maybe I just need to start a new one:

On a carbbed car, what is/are the advantages of a vacuum advance distributor, if any over mechanical? Or is it the other way around? What reasonably priced solution should I use?
I am pretty sure mine is vacuum challenged and needs replacing (my mechanic says I should replace it and seek advice from the 914 experts, since he is a fairly talented generalist)

Thanks
Sean

You can get more total advance out of a mechanical/vacuum combination with out burning up your motor. Under a light load the vacuum will advance your timing to take advantage of the lower stress on the engine. It should increase you mileage and power over a mechanical only distributor.

With the SVDA (single vacuum, dual advance (mechanical and vacuum)) that I purchased I don't notice any flat spots and acceleration just seems to come on a little quicker. What I mean by that is, say you're just tooling along at 45-50 in 4th gear with the pedal barely depressed at all, then the speed limit increases and you press the pedal in further with a plan to speed up to 60 and go to 5th gear. With the new distributor there just seems to be torque available with the slightest depression of the pedal but with the old one (bosch 009) there seemed to be a time delay and you just had push further before anything happened. I assume when pressing the pedal under this circumstance you are in the highly advanced situation so that's why it it's got more pep. This has been my impression of what people were always referring to as a 'flat spot'. Not completely sure if that's true or not. But, I can say I like this distributor.

034 svda

Thanks to both of you, I now know exactly what I will spend my money for. It was the distributor previously recommended, but I didn't understand why. . now I do. Thanks muchly.

Your carbs will need to have a "ported" vacuum fitting for the advance. Most aftermarket carbs do not have this out of the box.
It is a percision drilled hole with a vacuum hose nipple. The hole is blocked by the closed throttle plate and progressively gets vacuum as the throttle is opened.

Jim

Thanks Jim, I think mine is ported already, but I shall double check.
Sean

Are you saying that if I buy a set of Weber 40’s it will not have a “Ported Vacuum” out of the box?
I was planning on SVDA Dizzy with Weber 40’s on my 1.8 that is stock.

I've had 4 sets of carbs on 914's over the years (4cylinders)

only 1 of them had vacuum ports
most don't

brant

Aircooled.net offers installing a vacuum port as one of their services, in addition to cleaning and custom jetting carbs for your engine and altitude. They also sell SVDA Dizzies. That's the route I'm looking at, for a minimum of fuss. Haven't bought it yet, but I hear good things about them.