Timing gear sizes

[Nick Turley]

I have been working on my chummy engine rebuild today and am fascinated with how Austins managed to match up the gear sets.
My engine has never been stripped before and the gear sizes are as follows :-
Camshaft +7
Crankshaft +2
Intermediate -4
Mag drive +3

 I find that amazing.
Does anyone know how they did it ?

[Tony Press]

I have been working on my chummy engine rebuild today and am fascinated with how Austins managed to match up the gear sets.
My engine has never been stripped before and the gear sizes are as follows :-
Camshaft +7
Crankshaft +2
Intermediate -4
Mag drive +3

 I find that amazing.
Does anyone know how they did it ?

Some form of dial gauge assembly - drop the gear on a pin and the gauge gives the + - size ?

[Tony Betts]

Hi nick,

They baffle me a bit.

Most people know the top of the crankcase is stamped + or - which relates to the cam and crank gears.

But on the mag engine the sandwich caseing for the timing gears are also stamped in relation to the intermediate and mag drive gears.

The bit that baffles me is, I also have 2 gears here marked +7 for a coil engine cam gear. And somewere in the boxes ive seen a +12 and + 15

Yet ive never seen a crankcase marked over +3 and I've handled thousands of them.

Tony.