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Posted: Thu May 22, 2008 6:25 pm
by Packedup
Ah, that's what I was struggling to remember - Bearings not bushes!
I also forgot the ratios are closer. Not that I've noticed when switching between my Midget and Minor.
Posted: Fri May 23, 2008 10:33 am
by bmcecosse
Hmmm - any pointers to the change in the ratios Richard? I thought they were standard across all the boxes. Certainly Mini boxes were uprated with the needle rollers - didn't know that was extended into the in-line box. Did this happen about same time as the 2" main bearings were introduced on the engine - or do ALL Spridget 1098 boxes have the better bearings and gear ratios? Seems odd they would be building two versions of the 'same' box in the factory.
Posted: Fri May 23, 2008 12:24 pm
by IslipMinor
It came in earlier than the change to 1098, as apart from the Frogeyes, all Sprites and Midgets had the closer ratios and needle roller bearings - in both smooth and ribcase.
The Spridget ratios are:
1 3.200
2 1.916
3 1.357
4 1.000
In comparison to the 1098 Minor:
1 3.628
2 2.172
3 1.412
4 1.000
There were also two different gearsets 'A' & 'B' used in the ribcase, which makes swapping parts more limited.
Posted: Fri May 23, 2008 11:37 pm
by mike.perry
I have just had my 1275 Midget box rebuilt by John Evans and re-installed it onto the 1275 Midget engine using the diaphram clutch and keeping the Minor clutch linkage.
With no modification this results in a very heavy, very sharp clutch which soon takes the fun out of driving in traffic jams.
The solution is to increase the length of the relay lever arm on the pedal side by 1 inch. This increases the pedal travel and reduces the weight to about the same as a 1098 clutch. Despite the much less bulky diaphram mechanism compared to the 1098 unit there is still room to adjust the clutch rod. For added refinement use a roller thrust bearing available from the Morris Minor Centre (Birmingham).