Vacuum advance dist. for Model A

[Bruce of MN]

Originally Posted by Hitman

Most carburetors are designed for distributor advance, mechanical, centrifugal or manual. It’s best to match the distributor advance mechanism to the carb advance. Just because it fits doesn’t mean it’s appropriate.

Pardon my ignorance, but what is carb advance?

[Hitman]

Originally Posted by Bruce of MN

Pardon my ignorance, but what is carb advance?

Most modern carbs are designed for the distributor type they came with. For example, VW's run a variety of Solex carbs. The most popular Solex 34 PICT-3 is designed to run with the aluminum bodied Bosch vacuum advance distributors. When you put the mechanical advance Bosch 009 distributor on with that carb, they have a flat spot because the distributor ins't advancing like a vacuum distributor does. So it creates a flat spot until the distributor catches up to the carb. During VW's air-cooled era, they had at least three dozen different distributors they used in production.

Bosch 009's are good distributors, but are often times put on an engine as a bandaid to the real issue, often a poorly matched carb to a vacuum distributor. I have VW's and I don't run 009's, I use the pertronix distributors or early 010 or 019 distributors with mechanical advance.