MTFCA Forum

The judging guidelines says the carburetor adjustment was changed in 1925 to a bent rod design. What is that supposed to mean? Here is what I know. Sometime in mid 1925 the carburetor adjusting rod was changed from 3/16" to 1/4". At that time the 1926 carburetor adjusting rod was changed, but when? The knob is new, the rod is new, AND, the dashboard was changed to use the new style adjusting knob. There is now a deeper indentation in the dashboard for this knob. When exactly did all this happen?

The bent rod they are referring to is probably the rod from the steering column to the carburetor. They are not clear in the increase in size for the carburetor adjusting rod, and no mention of the knob itself. There are seven different lengths of adjusting rods from 25-27. It took me a long time to find the one for my car which is 24 1/8".

The rod from the steering column regulates the throttle opening. Those with the vaporizer had the rod across the top of the head with a swivel and those with the NH carburetor had a hole in the center of the block and the valve cover to operate the throttle valve in the carburetor. The fuel adjustment rod on the earlier cars was through the firewall behind the dash. It had a forked connection to the needle valve. On the later ones there was a swivel at the top of the carburetor and the rod moved in and out of a square hole in the rod at the top of the swivel for choking and a wire connected it to the choke valve. which was spring loaded and would close the choke when you pulled the rod but the spring would open the valve when the rod was pushed in. The mechanism is a bit more complicated then the earlier ones, but must easier to use because the same rod is used for fuel mixture and choke.
Norm

Larry, your question is about the 25 open cars so I don't know if this helps. Maybe it provides some timing context.

From CD version of the Encyclopedia page 759-April 29, 1925 Ford Factory Letter:

"A combined priming and carburetor adjusting rod is now standard on all Ford closed cars, and is being furnished without extra cost. Where formerly the driver primed from the instrument board and adjusted the carburetor from the dash beneath, both operations may now be performed from the same accessory on the instrument board."

From Judging Guidelines, 7th Edition

1925:

‘Bent upper end” refers to the triangular handle used on carb adj. rod. The choke rod has round alum. knob.

Later is the combo carb adj. and choke / with u-joint, using just the round aluminum knob.

Similar u-joint design used on Vaporizer carb too.

The judging guidelines don't go far enough. Ford redesigned the dashboard to accommodate the new style adjusting rod, which is now 1/4" not 3/16" as was used earlier in the year. Because of the new style knob, the indentation for the knob is now recessed deeper into the dash.