Can someone shed some light on why the timer roller is being pushed so far out on the camshaft? Is it just a collar from a distributor setup on the camshaft or what?
Maybe the year makes a difference but our 12 is just like that and it works fine, we changed the cam shaft last fall and the new one is the same, we use Tiger Timers,
This sticks out so far that a new day timers bush pushes the timer out and causes it to rock as the shaft spins.
The last time I saw that it was caused by a repro cam gear that had the hub about .100 too thick. The guy making the gear decided it would be stronger if he made the hub thicker and maybe it was but the cam nut then was .100 further forward and the NEW DAY timer many of us were using would have the brush pushed forward by .100 too and that did exactly what you described. The ND timer was quickly destroyed because the brush spring was totally squashed but the thing still needed more room for the spring since that spring well was then not deep enough. I later notched the backside of my ND brush so that its smallest diameter sleeve sat against the flat shoulder of the camshaft as it should and then it all worked OK but that thicker gear maker was somebody I was not happy with since I ruined a ND timer too before we all found out what was doing it.
I read somewhere that the nylon cam gears are thicker in the center, and come with a special, shorter nut to compensate for the added thickness. Maybe it has a nylon gear with the wrong nut.
All you need to do is file a notch on the back side of the brush, so it will clear the cam gear retaining nut. That allows the brush to seat against the camshaft as it should. Problem solved. Shouldn't take over five minutes to do this.
I agree with Larry and said so but I also wanted folks to know what the source of the issue was so they could save a lot of future grief by checking the cam gear hub before they install the gear since getting a correct gear makes every timer work just fine without modification. Timers have a way of quitting when you are on the road and no extra brush already modified is at hand.