I need a lesson on distributors

paulrhd29nz

I need some education here please.

I was looking at my 1946 8cyl and noticed for the first time that there is no vacuum advance. I went to the barn to look at my spare motor that is 1948-52 8cyl and it has vacuum advance on the disttibutor?

I have many pre 1930 hudsons cars so im am very used to the manual advance and retard.

 

So My question is when did vacuum advance come into play?

What is the differance in the distriutor from 1946 to the last version of the Hudson 8cyl?

Is the cam grind differant, or is the differance just in the weights?

and lastley, could one switch distributors from one series to another?

Thanks

Park_W

Paul, the distributors on the 8-cylinder cars are pretty much the same from '48 through '52, the last of the eights.  Pre-1948 8-cylinder engines did not have vacuum advance; 6-cylinder engines had vacuum advance starting with 1940, when they moved the distributor to the rear of the block.  The vac advance on the 4204-A distributors ('48-'49) started a little later and advanced less than did the 4204-B (49-52).