General Tech Distributor Gear End Float

[KVH]

Factory spec here is about .005 to .007 as I recall. Using the crude "feeler gauge in the pedestal space" test (with a washer under the gear), I'm getting .014. The Manual says to use a packing gasket if there is insufficient end float. What does a person do if the end float is too great, or is that OK?

 

[CJD]

The "packing gasket" is just a thin washer...or use a thicker one than you are currently using.

 

[TR4nut]

I think the float is too much already, right? I've not had that problem, can you see heavy wear on the bronze bushing surface, or maybe some wear marks on the distributor gear? If its possible for you to try, I'd be inclined to swap in a different pedestal assembly, it may be that someone removed some material off the base to give that clearance. I'm not sure how critical it is, but I'd try other options before trying to replace the bronze bushing.

 

[TR4nut]

Had another thought - with the washer trick, take a good look at the washer you used, no burrs, flat etc - I think you could easily have a false measurement using the assumed washer thickness if there was anything making it not lay perfectly flat.

 

[dklawson]

This is from memory and not specific to a TR4. Please correct me if I am wrong.

I believe the drive gear runs in a steel bushing in the block. The bushing is removable (tap it out from below, knocking it through the entrance for the distributor shaft). You can then tap the bushing back down to a different installed height if the drive gear play is too great with no shims.

 

[CJD]

Also, the car will run fine with .014" float. Extra float can allow the drive gear to lift or bounce under some conditions, which would alter the spark timing a degree or two. For most of us (namely me), a couple degrees of timing is imperceptible. I suppose if the clearance got crazy big, when it bounced it would send an impact load to the oil pump drive shaft, leading to a sheared shaft tab.

 

[dklawson]

Sidebar (non-Triumph): In college I had an old Toyota Celica with the 18RC engine. The dizzy was driven off a jackshaft that also ran the oil pump. While home on spring break the jackshaft helical gear driving the dizzy "failed". The teeth had worn paper thin. Eventually the teeth "folded over" so the ignition skipped time. Prior to that I had noticed a significant drop in fuel economy. However, I certainly did not expect that my poor gas mileage was due to severe wear in the dizzy drive gears. My spring break plans changed immediately as I scrounged to find a good used jackshaft and install it.