Trials, Tribulations and Triumph in the speedometer world

[22centerdoor]

Several years ago I purchased a Stewart-Warner 160 speedometer for my Model T. The unit was in great shape and installation was straightforward. After awhile the speedometer dial would not register past 5 – 10 mph no matter how fast I was traveling. I sent it off to Russ Furstnow who went through the unit and gave it a clean bill of health. I put it back on the T but the same problem showed up again. All the moving parts seemed to be working so I just left it in the car and lived with the fault. Then after a couple of years of this, all of a sudden the speedometer started registering the speed correctly! I was so excited! But it was short lived. Just as sudden the dial went completely dead. Now I was determined to find out what was the problem. I got out Russ’s speedometer book and tore that head apart as that was the most likely source of the problem given all the old pot metal parts inside. I could not find a badly worn or faulty part! Dejected, I put it all back together. Before installing the head back in the dash, I had my wife check to see if the speedo cable would turn when I spun the front wheel. No go! Hmmm. It was turning a couple days before that. So I next disconnected that cable at the swivel. It was not turning. So I removed the unit and placed it on the work bench prepping myself to tear into that swivel. I first spun that little fiber gear to see if the swivel output would turn. It didn’t!! What’s going on? Upon close inspection, I noticed that I had originally used a very thin cotter key to hold that gear in place. Over time the cotter pin got so mangled that the gear was spinning on the swivel shaft!! Boy did I feel stupid but extremely relieved. I had a good laugh and used a nice thick cotter pin! Put 50 miles on the T yesterday when going to a local car show. Speedometer worked perfectly!!!

[DHort]

The smallest part of the setup, the cotter pin, caused the biggest issue. Isn't that normal with a T?