The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Mr. D on 13.01. 2007 13:00

Title: Timing gears
Post by: Mr. D on 13.01. 2007 13:00

Hey i was having a little problem in finding a new set of timing gears, eventualy when i found them i had yet another problem:

Crank pinion = Steel
Idler gear = Endural Aluminium
Camshaft gear = Steel

Is it possible to use Endural Aluminium with steel? what are the possible consequences?

Title: Re: Timing gears
Post by: bsa-bill on 13.01. 2007 15:09

Should be steel. don't know how an alloy one would stand up to wear considering the next cog drives the camshaft.

All the best - Bill

Title: Re: Timing gears
Post by: Mr. D on 13.01. 2007 15:13

cheers for that bill, i have found a steel idler pinion on ebay, it is a lil expensive but i may just go for that.

Title: Re: Timing gears
Post by: LJ. on 13.01. 2007 19:52

I think I would agree with Bill on this.... I remember years ago fixing the gear wheels in an old antique clock. The wheels were all made of Brass and as the quality of brass is not the same as was years ago the clock repairer recommended a steel wheel to replace the broken brass one. Needless to say the steel one wore away the brass one. I have since learnt not to mix hard metals with soft.

Any decent clock restorers out there?  :!

Title: Re: Timing gears
Post by: dpaddock on 17.01. 2007 16:55

Beg to differ, guys, at least intrinsically.
Corvair, for example, had an aluminum cam-drive gear, and the cam ran on aluminum bearings.
The only problem with a correctly designed aluminum part running against a steel part is if the lubrication should fail. (In which case the steel against steel parts would also fail.)
There are countless examples of aluminum/steel gear pairs in the automotive world.

Title: Re: Timing gears
Post by: dpaddock on 20.02. 2007 22:29

In fact, Eddie Dow offered an alloy idler gear for the A10 in the '70s, and he was no neophyte.