I have a '26 Roadster with a Bosch T448 distributor system that has a noticeable wobble due to a worn bushing in the distributor mounting plate. (The distributor by itself is not the problem.) I measured the opening in the distributor mounting plate (Timing Cover) to be 1.065", while the distributor mounting shaft measures to be 1.055". I'm hoping that correcting this .010" of wobble will eliminate an annoying hesitation/miss at higher rpms.
Just a little background...the mounting plate appears to have a machined bushing (babbitt???). I'm not sure if I should make a cylindrical shim or if I should just have a new brass bushing machined into the mounting plate. I've been searching for a replacement bushing but I can't find anyone that offers a replacement bushing for this Bosch T448 setup. I would love to hear recommendations from those of you that may have experienced this problem already!
BTW...I'm very aware of the differing opinions regarding the use of a distributor in a Model T. I sorta enjoy the banter so feel free to T-off with your opinions. This one was installed by my Father many decades ago so it going to stay on the car. ;)

In truth Bob I wonder if the wobble you speak of is really what is causing the miss. The thing to ask is whether the wobble really affects the "running" timing or just the initial setting. It would have to wobble a long way to change the timing enough to actually cause a cylinder to miss completely. I am more wondering if what might be happening is the looseness of the whole thing is resulting in a bad ground being provided via the points. Before you do a whole lot of work, take a #14 wire and connect it solidly from the points mounting plate at one end then directly to the engine block at the other end. You don't have to do it too neatly just to test this out. If that fixes the miss then you can decide how to make it look better and stay in place. Just an idea and shouldn't cost too much to try it.

I agree with John R. Not on Ts, but other old and antique cars, I have run some really loose distributor shafts with no apparent miss or trouble. I am sure there would have been an eventual failure in the long term. .010 inch loose just doesn't sound bad enough.
Bad ground, weak coil, weak capacitor, poor electrical path through either the cap or rotor all top the list of high speed miss. A simple ohm-meter test of the cap and rotor is not enough, although I do it often.
I am not familiar with the model number. Is this an original vintage set-up? They are notorious for some problems due to age and lack of proper new replacement parts. But some of the adapted modern distributors have a different set of notorious problems. The rotor on some of the VW distributors can fail inside so that they test well with the ohm-meter, but will not run the car. However, they usually become hard to start first, not a high speed miss.
The carburetor could also cause such a hesitation/miss. But I would put the coil and/or condenser at the top of my suspect list.
Drive safely, W2

Modren Bosch disturbutors with worn main shaft bushings I've run on my vintage Allen distributor machine show irregular timing, but not missing. A Pertronix in the same disturbutor makes the timing steady as a beacon.

rdr

Thanks for the help! I'll try the ground wire. We used to have a ground wire from the distributor to the Generator case but it got removed some time ago. Maybe that's when my trouble started???
Concerning the setup, I expect this is vintage as my Stromberg OF and the Bosch T448 were orginally from on an old "hotrod" setup with a Frontneck head. Sometime during the late 40s, or early 50s, my Dad picked up the carb and the distributor but he's kick'n himself for also not taking the frontneck.
I have had some recent carb issues with my Stromberg OF but I don't believe it's the problem since the hesitation happens whether I'm accelerating or simply on cruis'n down the road.

Thanks again!!

Distributer? In a model T? Whats the world comin' to? (I just had to say that!) Have fun, KB

It's fixed!!! As John and Wayne suggested, I put the ground wire back on the distributor and it's runs as good as new! (Not exactly sure why I ever took it off to begin with???) Sounds better, runs better and there's no hesitation what so ever. I appreciate the help with fixing a simple problem with a simple solution.

PLEASE don't tell anyone that I helped you fix a distributor problem. I am supposed to only make things worse so you will convert back to coils/timer - ha ha. Since your dad put it on - that makes it special in my mind and I thus made an exception - just kidding.

John, I'm sure no one will tell Coilman.

Several friends have had that missing ground wire distributor problem.

Common problem with Bosch front plate distributors.