12 months ago I installed what is supposed to be the best layshaft you can get for a mini gearbox, in March when I had my engine in bits I took it out and checked it, finding that it had damage in the usual place, the hardening wearing through at the skinny end, where the laygear pushes against it. It was a brand new layshaft, a new old stock Leyland 22G1040 laygear and new bearings

I reckon it's a silly design that the shaft is held in place while a very stressed gear spins on a pair of little roller bearings

I wonder if we could we rearrange it so that the shaft has some opportunity to rotate in the housing so that it's not always wearing in the same spot, or something along those lines

thoughts?

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did I tell you that I won a trophy?

Get an A+ Gearbox with a thick layshaft

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Starlet Conversion:
http://www.ausmini.com/forums/viewtopic.php?t=15484

Josh prefers a thick....

No No, (Apologies) sorrry I just cant bring myself to be that juvenile!

Although...... It is Friday

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Sir Alec! we are not worthy!

Simon, I believe there are some expensive gearbox's being made in the UK, Swiftune and the like that have things like two and three part lay gears, and oil feeds to hollow layshafts etc.

Try looking on Turbo Mini's ?

http://www.turbominis.co.uk/forums/index.php

Edit... Bingo! check these threads out!

http://www.turbominis.co.uk/forums/index.php?p=search

http://www.turbominis.co.uk/forums/inde ... tid=212545

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Sir Alec! we are not worthy!

Simon, those threads seem to be pointing towards:

Was yours one of these?>>>>>

[Quote]
Heritage MG Parts,
97-103 Victoria St,
Smithfield NSW
2164 Australia.

email Max at [email protected]
website www.mgspareparts.com.au
phone 61 2 9609 3988
fax 61 2 9609 3955

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Sir Alec! we are not worthy!

Simon, i have a 2nd hand shaft here that we pulled out of a 16year old 1415cc stroker roady box & it has 2 big ar$e Bushes fitted where the leyshaft bearings would normally be,,, now at first i thought "NO-WAy would the layshaft be any good & surely the bushes would be stuffed,,,, BUT!!!!!! They`re all in great condition & still measure up fine & dandy

I must say that this particular leyshaft was definately one of the old skool "Proper" leyshafts sold way back in the mini "Hey-days" so it`s probably a lot stronger than what you get these days , but still,,, maybe the "bush" trick would be worth looking further into cause the std issue bearings system always chew up the shafts hey? ...

I think i`ve only ever pulled "ONE" good condition leyhaft out of a 2nd hand box in my life (& obviously i`ve pulled apart a kazzillion mini boxes in my time) & this shaft was it

Just something for you to think about ... OH!! & yes i still have that shaft & it`s corresponding bushes here,,, just kept as a keep-sake & talking point

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

yes Graham, it was a Heritage MG one (disclaimer: I'm not doubting the quality of it, compared with the rest that are on the market today, just doubting the fit for purpose of the way the gearbox is set up for competition use)

thanks for the links - looking and searching



that's very interesting Matt.... very interesting indeed

I'm planning on pulling it out and taking it to an old guy in my car club who used to rally all sorts of cars (still has his '62 850 he bought new), he's a tool maker in the true sense of the word. I'll see what he thinks about bushing the gear. I assume the laygear and shaft are 'normal' but they've pressed bushes into the gear instead of the bearings?

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did I tell you that I won a trophy?

No they`re floating bushes,,, that`s partly why i totally expected the shaft & gear to both be stuffed .. & the other part of this equation is that i know how much grunt that particular stroker had & also what treatment it copped in all those years of flogging so i was totally expecting it to all be stuffed,,, But it weren`t

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

I would just ask your toolmaker to make you a layshaft from some decent steel. Case hardening should be RC61 or better.
I would also ask Max about it. Maybe the heat treatment it got was faulty (they get sent away for that).

<edit> Caning it in 1st gear (as in khanas) is pretty hard on Mini layshafts....

Real gearboxes these days have a stub shaft on each end of the cluster, with 2 real bearings (my Fiat had 3). But a Mini box uses what started life as a Morris Minor gearset, designed by people who drove around in 4th gear.

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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.

Have you considered oil feeding the layshaft. run a oil pipe from the engine down to the gearbox then feed it into the layshaft. Im not sure if the layshaft would have to be machined. But it wouldnt be too hard. May worth thinking about anyway.

think about the problem. If you make the surface of the shaft too hard then the needle brgs will wear. It is cheaper to replace a shaft than a lay gear.
Matt is correct about the bush idea. A needle roller brg does not have good load capacity[ ie area of contact. approach angle etc etc]. A bush has a better load carring ,but it will fail when the revs exceed the load capacity and generate too much heat.

Craig's idea for a oil feed is good, but getting it to the correct position and lubricating capacity will be a problem.

I have also looked at various mods to the layshaft set-up along with the taper roller brgs and have a few ideas but not put one together at this stage.
With everything people do to their cars ,COST is the most critical thing. Sure some of these set-ups from O/S are better than original, but at what cost.

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Research is the difference between speculation and investment. Anyone who copys some one else will always be second
www.minisprintgt.com

isn't the problem that the load on the needle bearing is too high for the film of 20W50 oil to remain between it and the layshaft? Hence the wear.

reduce the load or get a better oil that maintains the film - neither of which is really a cheap and easy option given the constraints of using the sump as the gearbox and space.

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the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates

Roller bearings do not need a lot of lube.
IMO the problem with recent layshafts is the rollers deform the thin case hardening, which then flakes away. One cause of this is poor core strength of the shaft material. Good steel costs good money.

If bushes are better, why did BMC fit rollers instead to 2nd and 3rd gear on all boxes from the 997 Cooper onwards?
Those 850 bushes used to seize or break up in competition.

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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.

would 6500rpm in 1st gear be too much for it?



that's what those links Graham posted from turbominis were talking about, one guy was having a go at it but there hasn't been an update since 2008

what feeds the shaft with oil now? just splashing?

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did I tell you that I won a trophy?

Oil is fed in from the top, above the thrust washers.
There is a veritable oil fog in the crankcase with the engine revving. Oilz goes everywhere.

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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.