Hi guys, I would like to know what is recommended when rebuilding a gearbox to go under 100+hp? The casing is a 22G1228. I will obviously replace bearings etc but what about bulk rings? Is there anything that needs to be uprated for the torque? Standard type diff or X pin? Any advice would be appreciated.
Thanks

_________________
1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

I've got north of 125HP at the crank, and I'm running stock drop gears, Mk2S gearbox, 3.647 diff, with a comp diff pin and spider gears.
All bearings were replaced, and the baulk rings were back ground .020" for greater life.
It's only a road car; for khanas etc you would want a 4 pin diff at least, or a Quaife.

If buying new baulk rings I would try them on a gear for fit. If they rock about, do not buy them. They will be worn out before bedded in.
New current baulk rings from Minis Plus and Karcraft seem OK in this regard.

_________________
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.

What part of the baulk ring do you take the .020" off? Do you need to do anything special with the drop gears? You seem to have a lot of handy little mods for making everything better!

_________________
1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

A standard baulk ring is about 0.350" thick, It is about .040" clear of the gear dogs when new. It will stop working when there is no gap left.
The very best baulk rings were the forged steel ones made up until ~1970. These had forging lines and sometimes cutter marks on their periphery.
Since then, most are pressed in a sintered powder process, some are better made than others.
You can grind .020" off the FLAT face of the ring that goes towards the gear, to get more life. provided it is at original thickness.

Helical drop gears are fine (and quiet!) on a road car, I've not had any problems at all.
Just check the primary gear and idler gear end floats are within spec, I use .004-.005" for both.
If assembled much too loose, the end thrust can wear the gearbox case or break the primary gear's bronze thrust washer.

_________________
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.

Thanks for the info Doc. Your a big help.

_________________
1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

If rebuilding the gearbox I put new idler bearings in unless changed recently.
They are cheap. But if neglected and they wear right out it can stuff the flywheel housing, the gearbox case or both.

_________________
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.

Another gearbox related question, does anyone know what comes in the gearbox bearing kit from Karcraft? Its only $150 odd dollars. When you look at bearing prices from other suppliers it seems really cheap. I need to replace every bearing as it had bearing failure that went through the whole engine
I would have to buy diff bearings and idler bearings also but want to make sure I get everything required. Cant just go down the road and get a forgotten part down here.

_________________
1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

I know it includes all the gearbox bearings, but not the 2x idler gear needle rollers. They are extra.
I am not sure about the 2x diff bearings, I think they are extra also. Ring and ask.

_________________
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.

On tomorrows to do list.

_________________
1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

Slight thread detour,

any comments, thoughts experience with the new roller type idler gear bearings available now fromMed/ Swiftune ( each slightly different i think)

I asked them the same thing a few weeks ago:

MSG20 G/BOX OVERHAUL KIT - MINI (4 SP SYNCRO)(NO DIFF PARTS) 1.9000kg

13H7848 <B> BEARING - IDLER GEAR - MINI - ALL SYNCRO
HYL8473 <A>. BEARING - VARIOUS - LAYSHAFT - MG MIDGET+MINI (ROLLER) x 1
HYL3616# <B> GASKET SET - SUPPLIMENTRY - MINI x 1
HYL3614 <B> GASKET SET - G/BOX - MINI x 1
22G931# <B> LAYSHAFT - MINI (ALL SYNCR)(UK MADE)(64 ROCKWELL) x 1
AAU1365 <A> BEARING - MAINSHAFT - MINI (DOUBLE ROW) x 1
ADU7619 <A> BEARING - 1ST MOTION - MINI - ALL SYNCRO x 1
HYL8474 <A> BEARING - 1ST MOTION - MINI - 3 SYNCRO+ALL SYNCRO x 1
CHM141 <A> BEARING - LAYSHAFT - MINI - ALL SYNCRO (ROLLER) x 2
22G2033 <B>. BAULK RING - VARIOUS - AH SPRITE+MINI x 4

_________________

Timmy that's the gearbox overhaul kit you listed.

The bearing kit `KIT4SYNCHRO' has no idler bearings, I bought one recently.

_________________
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.

Oops. It's the $330 kit less diff parts. If you were doing a gearbox overhaul you might need the rest of these bits anyway

_________________

at least get a cross pin diff - a new "competition" diff pin and new spider gears still isn't as good as the originals... they'll wear out pretty quickly and start shoving crap through your motor

_________________
did I tell you that I won a trophy?

So I rang karcraft and got the info I required. Thought it was to cheap to have all the bearings for the gearbox.
AAU1365 <A> BEARING - MAINSHAFT - MINI (DOUBLE ROW) x 1
ADU7619 <A> BEARING - 1ST MOTION - MINI - ALL SYNCRO x 1
HYL8474 <A> BEARING - 1ST MOTION - MINI - 3 SYNCRO+ALL SYNCRO x 1
CHM141 <A> BEARING - LAYSHAFT - MINI - ALL SYNCRO (ROLLER) x 2
HYL8473 <A>. BEARING - VARIOUS - LAYSHAFT - MG MIDGET+MINI (ROLLER) x 1

_________________
1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt