Hi Everyone,

I have a mk2 S box in my Austin. Recently the input gear bearing gave up which resulted in the inner of my input gear and outer of the end of the main shaft being scored and damaged.

I have the gearbox in peices and am struggling to find an acceptable 4 speed mainshaft and dont really want to pay through the nose for a cooper s input gear if I can find one.

So basically, as far as I can tell I have three options.

Firstly, just find a decent mainshaft and reassemble it as per usual and get the inner of the input gear sleeved to suit the K14.

Or I can get a caged needle roller bearing like the idler gear bearing and just get the input gear bearing bored to suit it. I am led to believe I can bore these out 18mm safely (although that diameter shouldnt be necessary)?

Or I could try and get a couple of roller bearings with an external and internal wall and get the input gear and main shaft machined to suit the bearings. I thought of using two so it gives it more support.

What have other people done? Did it work?

Also, What would be considered an acceptable diameter for the mainshaft? I could always get it machined and then sleeved to get it back to the original diameter.

Thanks in advance,
Matt

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Contact me, I have a reconditioned mainshaft in stock.
I machine the nose down and fit a 14mm OD hardened bearing inner ring.
If it ever wears you can replace the ring.
I've done 6 or 7 over the years including Mk1 S and Mk2 S, never had a problem.
$75 including post, exchange if possible but not essential.
http://home.exetel.com.au/zoomini/zoomi ... GP2113.JPG

Here's another one I prepared earlier- it's a 14mm shaft that's had an 18mm OD bearing ring fitted, to suit the later 18T 1st motion shaft (input gear). Same price.
I've done about 4 of these. One is in my 1412 stroker.
http://home.exetel.com.au/zoomini/zoomi ... GP1472.JPG

You can save your old S input gear if you get the bore ground out by a toolroom and a hardened bearing sleeve fitted.
An ausmini member recently had this done.
Note that a sleeve is needed because the gear is case hardened- if you machine the bore out it'll then be soft.

Alternatively, I'd contact Mini King, John Smidt may have a s/h S gear that suits.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.