Triumph Repair: TR4A Distributor drive gear, mesh pattern, cam bearings

Question
Howard
I have a 1966 TR4A.  When I bought the car i was advised it needed a new cam.  I installed this last year.  After 20mins of running the cam gear and dizzy gear had chewed each other up (this was the original problem!).  I sent the engine away to be rebuilt.  It now has a new camshaft, new oil pump inards, new cam bearings, and new dizzy drive shaft and gear.  I was setting the static timning when the distributor came very loose and free of the mounting.  I noticed on the 'step' where the dizzy fixes to the engine mount there was a significant amount of the aluminium missing.  I took the mount off and having removed the dizzy drive gear it appears (unbelievably!!) that the 2 gears have started to eat each other again (only very slightly).  I should explain that since the rebuild the engine has only been turned over on the starter motor to get oil pressure - perhaps for 30 secs.  I'm thinking now that the only possible explanation is that the distributor itself was not flush with the engine mount (because of the cracked step).  Could this cause the dizzy gear to be pushed offset to the camshaft gear?  Can you give any other advice?  I should say that float for the dizzy drive shaft was checked on both occasions, as was the end float on the cam.
Many thanks
Tim

Answer
Hi Tim,
You need from .003" to .007" end float in the drive gear (up and down free play) when it is all tightened down. You also need to confirm that the cam gear and the dist drive gear are a matched set.

All of this should be done before the oil pump, head or cam chain is installed. confirm the end float and use white lube or such to confirm the gear mesh pattern.

You need to purchase a service manual for this engine as there are many "traps" in ALL engines that can cause these types of problems.
Howard