Hi all, I took my 1923 touring / pickup conversion for a 50 mile drive today (drove the T to the golf course and met my brothers for 9 holes of golf).
A couple of times during the drive, the car would start to misfire and I noticed that the travel of the timer adjustment was more restricted than normal (couldn't get full advance). So, I pulled over and shut the car off to take a look. Nothing appeared to be out of place, and the timer rod travel had returned to normal, so I restarted the car (it fired right up), and I went on my way.
Has anyone else had these symptoms? My theory is that the timer case is occasionally popping out of place due to the vibration. Shutting the car down removes the vibration and the timer pops back into place. The clamp appears to be holding the timer case down properly when the car is shut down, but I haven't checked the clamp bolt torque yet (I will check it when the car has cooled off).
Tomorrow when everything cools down, I'm going to take the timer off and doublecheck the wire routing and tightness of all the connections.
If you find that everything else is OK and you think the timer is jumping out of position, it's the tension on the hold-down clamp, not the torque on its bolt that needs to be looked at.
Possibly the clamp needs to be re-bent a bit.
The only other thing that comes to mind is that the fan belt is travelling over to the point where it rubs against the timer or its control rod. If there's any indication of this, like shiny places on the metal, try tightening the fan bracket bolt. Flat belts inherently travel to the middle of a slightly crowned pulley, if the pulleys are parallel. If they're not, it will travel - interestingly, to the high side!
Good point Peter,....and I might add that usually, the fan belt rubbing on the timer is due to the wrong size belt which when tightening the belt, brings it too close to the timer. The proper size belt prevents this,....just a thought,.....harold
Thanks for the ideas, I just found the problem - the previous owner had installed a tie-wrap around the timer wires, up too close to the timer case. By watching the timer while a friend was moving the timing rod up and down, I could see that occasionally the head of the tie-wrap would catch on the timer clamp.
Further pressure on the timing rod while the tie-wrap was hung up on the clamp would result in pulling the timing case up slightly off its pocket, causing a misfire.
I moved the tie-wrap further down so that it never comes close to the clamp for the full movement of the timing rod.