Two contact points versus One contact point - 1929 Chrysler "75"

[JRA]

Hi Everyone,
I own a 1929 Chrysler, model "75", and its distributor is a Delco-Remy model 659-B, what I believe is the original one. The car owners manual presents such distributor with two contact points. My car is operating very weel, no missing cylinder, but its distributor has only one contact point. When I open the distributor, I can easily see space for a second contact point, as you can see in the picture. I was told each contact point would deal with three cylinders, but as far I can listen well, all six cylinders are operating properly.
What is the purpose of such second contact point? If the car needs two, what malfunction occurs when using just one?
Thanks
JRA

1928 Chevrolet National, touring
1929 Chrysler "75", roadster
1951 Plymouth Cranbrook
1954 Willys Jeep CJ3B

[hchris]

Hi Everyone,
I own a 1929 Chrysler, model "75", and its distributor is a Delco-Remy model 659-B, what I believe is the original one. The car owners manual presents such distributor with two contact points. My car is operating very weel, no missing cylinder, but its distributor has only one contact point. When I open the distributor, I can easily see space for a second contact point, as you can see in the picture. I was told each contact point would deal with three cylinders, but as far I can listen well, all six cylinders are operating properly.
What is the purpose of such second contact point? If the car needs two, what malfunction occurs when using just one?
Thanks
JRA

1928 Chevrolet National, touring
1929 Chrysler "75", roadster
1951 Plymouth Cranbrook
1954 Willys Jeep CJ3B

Its been modified to make life easier with one set of points, a sensible way to go

[ply33]

Looks like only one coil is provided for so I would assume that the second set of points was to increase dwell time for better coil saturation without sacrificing point gap and thus arcing. Dual point distributor were used with that setup for lots of years for better spark and thus better performance. And I understand that you can remove one set of points and they will still run.

But for me this is all hearsay as I've never dealt with such a distributor. But I suspect that if you can get a person who worked on hot rods in the 1950s or 60s prior to electronic ignition they could explain it and how to properly adjust things.

[TexRiv_63]

Looks like only one coil is provided for so I would assume that the second set of points was to increase dwell time for better coil saturation without sacrificing point gap and thus arcing. Dual point distributor were used with that setup for lots of years for better spark and thus better performance. And I understand that you can remove one set of points and they will still run.

But for me this is all hearsay as I've never dealt with such a distributor. But I suspect that if you can get a person who worked on hot rods in the 1950s or 60s prior to electronic ignition they could explain it and how to properly adjust things.

You are correct regarding a single coil system. A lot of classic musclecars used dual point systems for this performance reason. In the case of dual coil systems like a Cadillac V12 each set of points handled half of the cylinders so you could not remove a set.

[pre1939chrysler]

They need the 2nd set of points. The opposite side is hard to come by-NOS John brillman Co. does them for my customers. I have used ones.
Need wire wheel hub caps? I have prefect show ready set .