TR2/3/3A curious tachometer take-off

[Dr_Mike]

Our TR3A is made up of bits and pieces from TR2- TR4 but this leaves me flummoxed. The pedestal looks "normal" but has a brass insert (?bushing) with female thread on the end and an overly long ( by 9 inches or so) cable with male fitting. Cannot find any thing like it in catalogues so I presume it come from another marque. TR3 bushings are not listed anywhere I have looked, though I can get the gear that fits inside, and already have the correct cable , which obviously will not fit.

Any ideas where to go with this?


I forgot to add that the brass fitting is a few thou under one inch in diameter.

 

[CJD]

You are missing the bearing insert that screws into that female brass thread. But that doesn't matter, as the outer bearing in your picture is buggared beyond repair. You need a completely new tach take-off bearing.

Not a great pic, but you can see the inner bearing that is missing in your pedestal.

 

[Tr-Beg]

I see on the pic "valve clearance (cold) 0.013" and not the classic 0.010... What is the reason? Thanks

 

[TomMull]

John has an earlier TR2 with iron pedestals most likely. I think the Factory manual for that engine gives .010 inlet and .012 exhaust but .013 for both if doing "high speed work".
Tom

 

[Dr_Mike]

thank you John.
I did not find a decent pic/diagram to explain this. I am supposed to be resting after eye surgery but will try to sneak a peek. Inner bearing seemed firmly attached to the cable!

BTW My rocker pedestal is magnetic so I suppose it too is iron.

Michael

 

[CJD]

Here's a little better pic...

And an even better view. This is of the tranny bearing, but as far as I can tell, they are interchangable:

In this pic you can see a small hole on the underside of the outer bearing shell. At the factory a brass pin is jammed in there to lock the inner and outer bearing shells together. It is one of the more tedious chores in replacing the internal seal...drilling the pin out without damaging the fine brass threads. You can see the PO marks on the bearing...as sometimes they get glued in place with dried oil.