as the topic says i want to know how much power a normal mini gearbox can handle n what has to be done to make them handle more n not break as i am lookin at building a pretty hard 1275cc.

Well, my DEAD STOCK Rod-change is handling over 100HP @ Crank....

Ok, its getting a bit whiney, but then again, its never been rebuilt, just a "kerosene rebuild" last-time the engine was out. . . . .

Oh, and its on a Turbo 998, so it is making some pretty impressive torque high in the rev-range......

J

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well i am aiming for about 120hp @ the wheels with my supercharged 1275cc. Thats why i ask cause i want to know what problems to expect.

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hope be back on the road soon with a blown 1275.

j just dont take the car to redfern and say the gear box has a wine
makka

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Anonymous moderation means the agro that is built up towards the mods isn't aimed at an individual (fewer "Makk" attacks). Less stress for mods means less moderator "retirements".

I've got ~120HP at crank, thru a Mk2 S box..

`boostedmini' (1360 Metro turbo) has ~140HP at crank, thru a Mini-K box, no problems yet.

KAD twincams have up to 200HP at crank, and run a straight cut Mini box.

A lot depends how big and sticky the tyres are, and how sympathetic you are to the box.

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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.

oh ok cool. well im aiming for about 100-120 hp @ the wheels. So i shouldnt have to do anything to the box for a while then.

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hope be back on the road soon with a blown 1275.

No, provided you build it properly- all new bearings & layshaft, etc.
Diffs are a bit weak for lotsa power. Make sure you fit a competition diff pin & 2 new planet (spider) gears, at least. Or a 4 pinion diff....

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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.

Thats what Kev reckons anyway. . . .

Mine is a FLOGGED OUT CLubbie Rod-Change, whines like a dog on heat, crunches like a box of corn chips, and pops out of second at the slightest breeze .......

But its still Perfectly Good !!

Seriously, I'm about to order the "nasty rebuild" kit from minispares with the Competition diff pin, all bearings and gaskets....

Might even ask the good Dr to put it together for me .....
I'll have to do this before going to "the next level" I think . . . . .

J

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Careful James, apparently that gearbox rebuild kit is out of stock. You might have to order the parts separately.

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Lillee - 1969 Morris Mini K

You are a Shocker

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Stop Licking the Dog...I Don't Care Who Started It

so in other words my good one that iv got now thats running i should rebuild for the bigger motor or leave it as is??? If i have to rebuild how much would it cost me???

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hope be back on the road soon with a blown 1275.

I would strip and check it. Could cost you $200-700 for parts, depending what (if anything) is on the way out.
I bet the layshaft and its bearings are wearing out, for starters. They all do, except the A+ ones.

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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.

Pay particular attention to ALL the running clearances, especially the idler gear. What box is this btw, remote or rod change? As Kev says, if remote, the layshaft will need replacing. And don't forget the diff, really should be looking at 4 pin (cross-pin) diff with that sort of power.

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Steve