Centrifugal advance for a Bosch T distributor

[Reno Speedster]

I was reading my dogeared copy of the fast ford handbook, looking at period ignition systems. The section on Nosch distributors recommends the manual advance distributor for racing but says that the “…Bosch compensating system, with governor for automatically advancing and retarding the spark according to the speed of the engine, would be a convenient addition to a Ford sport model for general road use…” So, centrifugal advance is period.

I have had a couple original Bosch distributors but neither had an automatic advance. I am getting into a distributor mod for my speedster with a Rajo BB (Nissan distributor for double plugs etc) and it would be fun to do an automatic advance. I don’t have the Nissan dizzy yet but from the pictures, it has a vacuum advance (it may have both). The Bosch that came with my front plate distributor is fixed. I have looked into the previous posts and saw that someone was doing automatic advances for the Bosch T set up, but when I talked with them they no longer were. In any case, it probably would not work with the Nissan.

So, has anyone done an auto advance on a Nissan distributor for the T? If so, what did you use? In general, how much advance is needed for a Rajo T and at what RPM?

To be clear, this is a highly modified speedster. I know some folks will object to an auto advance on a T. That is not the conversation I am looking to have here.

[Henry K. Lee]

Advancement on the distributor has a lot of variables, ie, compression ratio, cam, fuel delivery. Now a burn check on the plugs are very important in getting it right. Did a few odd advancements, (But like the other guy, not doing them anymore. Sold my SUN distributor setting machine). You could possible modify an older (1970-1980) Mallory Adjust-a-Curve lower unit under the pick up plate. These work wonders in getting them on the money. I did a real odd one years back using 2 each Mallory VW Adjust-a-Curves with a chain drive. Really works well!

Hank

[RajoRacer]

The centrifugal advance on my Nissan RETARDS the spark on mine - one would need to reverse cut the lower gears, I'm assuming.

[TRDxB2]

I don't have the Fast Ford Handbook to reference. So for clarification when you say you are "looking at period ignition systems" what period?
In the early 1900's it was American Bosch (had centrifugal advance) and that is not the same Bosch that we think of with VW's (stock has wrong advance curve)

[Reno Speedster]

This was an article on ignitions used in model T racing cars written in the 20s. It covered a number of distributors and magnetos available to racers at that time. It would have been American Bosch at the time.

I am looking forward to getting the Nissan distributor to get to grip on what will need to be done to it. I think some modification and welding will be in the offing. If nothing else, to get rid of the vacuum advance.

[Les Schubert]

I’m not sure why you want to get rid of the vacuum advance? In my experience it can be very nice to have.

[Reno Speedster]

I am sure it would be nice, but they didn’t have them in the 20s. I am stretching it with the two plug distributor, but I just can’t afford the period pieces.

[Mark Gregush]

All T era Bosch 600 model types have some form of centrifugal advance. There are two types, the main one/most found/sold has a centrifugal advance that engages on start up, then full advance using the hand lever. The other type is fully automatic with no hand lever control. While the automatic type might have been fine for normal speeds of the era, it does not have enough advance for higher speeds.
Most of the Bosch 009 types that I have worked with would be the fully automatic advance, again might need to use the casting to add spark control rod to really use. The VW engine had a much different RPM range. The stock VW Bosch would have had a vacuum advance and pretty sure the centrifugal advance too.

[J1MGOLDEN]

There are too many variables to say any configuration is the best.

The Texas T setup has the 009 Bosch distributor turning in the opposite direction, evidently to eliminate the toggle advance used on most of the other Model T set ups.

Tony Wiltshire did a lot of rebuilding of those 009 distributors and he gave me a box of small parts he used. There are several sets of the small springs used for the centrifical advance, but I have no idea what the best selection would be, as they are different sizes.

The other problem would be the much lower Model T RPM might not let any of them work.

[Les Schubert]

Perhaps consider that ford was using both centrifugal and vacuum by 1932 on the V8

[Gene_French]

Gentlemen:
seems that i remember some of the Bosch dist. units on 1960's cars other than the VW that had facilities on the points plate for mounting the points to allow for either clockwise or counter clockwise rotation, and the counterweights were reversible ...with the correct spring and counterwieght combination a full automatic advance might be achieved ... it seems that these were Volvo or Saab dist. units ... perhaps some of our Eurpoean members would know this application ?...always an optimist...Gene French

[tselliott]

Dan McEachern sells the gears that rotate the Nissan distributor in the correct direction.

[David Greenlees]

Gentlemen:
seems that i remember some of the Bosch dist. units on 1960's cars other than the VW that had facilities on the points plate for mounting the points to allow for either clockwise or counter clockwise rotation, and the counterweights were reversible ...with the correct spring and counterwieght combination a full automatic advance might be achieved ... it seems that these were Volvo or Saab dist. units ... perhaps some of our Eurpoean members would know this application ?...always an optimist...Gene French

I've driven old Volvos for years and and I vintage race one because they wear like iron. The 61 to 68 B18 1800 has a Bosch 009 and it rotates counter clockwise.

[Gene_French]

David:
thank you for that info. ... i also think that several of the mid priced German and also the Sab sonnet had 4 cyl. dist. units that were of the correct rotation or easily reversed ... i have often maintained that a gear set that would allow correct rotation would allow auto. advance dist. for the model T ...one would need to match flyweights and springs to the rpm range of the Model T ... and yes, i have admired the older Volvo's for their mechanical durability ...always an optimist ...Gene French

[David Greenlees]

David: I have admired the older Volvo's for their mechanical durability ...always an optimist ...Gene French

Gene, Yes, that plus the postwar Volvos were patterned after US built vehicle from the 1930s to the '60s and have SAE fasteners, check into ours @ https://theoldmotor.com/?s=volvo