Last night while I was bolting up the 60-2 wheel, basically a stock FD wheel with a 60-2 ring welded onto the outside of it, I noticed that the bolt holes in the FD wheel center are larger than the 4 bolts that hold the wheel to the e-shaft. My 20b wheel is the same way.

I screwed the bolts in, but did not tighten them, and tried moving the wheel to see how much free play there is. I found I could move it about 8/10th of a tooth which is roughly 4-5 degrees. Since the timing wheel is sandwiched between the belt pulley and the e-shaft, I think it's possible that the wheel could shift a bit from the engine's torque on one side and the accessory resistance on the pulley side.

I don't think there is any real danger since I believe it would retard the timing unless it shifted the other way, and I can't think of a reason how it could (abrupt up shifting??).

FWIW . . . .

 

You need to get a FD front boss/hub along with the trigger wheel/pulley. Reason being the FD has two "pins" that the wheel goes onto, making zero slop. But that is only if you are really worried about it.

 

Drill it for a pair of roll pins. Or even blind rivets like Mazda used on some of the pulleys. That will positively locate it and you can forget about the slop.

 

Thanks guys. I think I am going to try to buy or have shims made to fill the gap. Pins are a good idea, but since it is already on the motor it would be difficult to drill precisely. If the shims don't work I guess I'll take the hub off and replace it with the FD hub .