Compare the gearboxes

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Compare the gearboxes

Postby Alice » Wed Apr 05, 2017 7:41 am

I have 4 gearboxes to play with, one of which is now restored, using some bits from others.
There are some intriguing differences in these, which may be of assistance in dating any non-original gearbox in your car or spares.

Boxes 1 & 2 came as separate loose items with OHC engine blocks 19383A and 26953A.
Both are 1930 engines, one from mid January and the other from Jun/Jul?
The later engine block will be the one used in restoration, along with box #1, which I believe would have been the earliest of the four.

Box #3 was fitted to 1931 SV engine 3343A in the Minor as I bought it. (See mag M 140).
Box #4 came with 1932 SV engine 13563A which I was given.

Box #1 has a tailshaft handbrake, as had Box #2, but #2 has a recess moulded in the top of the aft end of the box lid, whereas #1 does not.
The only explanation I can think of for that recess is a place to route the cable from battery to starter switch.
In both cases the footbrake pedal pivoted on the clutch pedal shaft.
Box #1 has 28 11 29 stamped at the bottom rear face of the box near the idler shaft bulge.
I haven’t found any similar markings on any of the others.

Box #3 has the same lid, with recess, and rear bearing housing as #2, but did not have a tailshaft handbrake, and there is no drilled hole in the lug on the rear bearing housing to take the linkage fulcrum pin for that type of handbrake.
The footbrake pedal still pivoted on the clutch pedal shaft.

Box #4 has a short lid and smaller rear housing, having the coupled handbrake. The footbrake pedal pivoted on a stub shaft mounted on the chassis frame beside the gearbox.

Box #1 had speedo drive with 4 start worm and 14 tooth gear
Box#2 has no driven gear and I can’t see the worm starts.
Box #3 had a 3? start worm and 11 tooth gear
Box #4 had 4 start worm and 17 tooth gear (this is now in the restored Box #1)
Why these different ratios in the space of two years and all being passenger vehicles?

Boxes 1, 2, & 3 have needle rollers between the input and output shafts, and box 4 has a bronze bush.

Footnote: Note the wine corks used to stop ingress of dirt, small creatures and moisture from entering while in storage under my house.
Pro:- Quick and easy efficient measure.
Con? Once the bottle is uncorked, the contents have to be got rid of somehow!

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Alice
 
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Joined: Mon Jan 08, 2007 4:04 am
Location: Brisbane, Australia

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