gearboxes

[plj]

When did the gearbox casings change from ali. to steel?

[Toby]

when the morris 8 was introduced?! all boxes I have seen have the main box in aluminium but the 4 speed bell housings might have been cast iron

[Ian Grace]

I'm pretty sure the two-piece ali/steel boxes were the 4-speed boxes and all of the 3-speeds were single piece ali. The 4-speed box was new for the 1933 season. The 1933 3-speed 2-seaters were all blue and five quid cheaper (still offered with single piece screen at a Hundred Pounds, but at least they were chromed!), but you could get a 4-speed 2-seater in blue, green or black. The saloon also came in blue, green or black and were all 4-speed. I suspect the tourers were all 4-speed too.

[plj]

Well that's answered the question, 4 a.m. normal time of awakening for old persons like me, and it suddenly occurred to me I could have a 4-speed box fitted. Crept out to the garage and yes it is, non-synchro version, so less original than I thought but not something I'm going to reverse. Now the next question is "are the input shafts common to all gearboxes?" Can't see why they should be different and hoping not as the scrap ali cased box I have has a reasonably splined input shaft.

Regards,

PLJ

[Ian Grace]

You're lucky - the 4-speed box is light years better than the 3-speed unit!

I'll check the input shaft part numbers tonight and report in the morning.

[Ian Grace]

As I suspected, the input shafts are all different.

The 3-speed boxes used part no. 36335, the 4-speed crash boxes (SV20713 to SV 34262) used part no. 37412 and the '34 season 4-speed synchro boxes used part no. 37799.

Interestingly, looking at the newly-completed SV Genome, there is no indication as to which 1933 2-seaters were completed as 3-speed 'Hundred Pound' models and which were 4-speed models for GBP 105. So we will never know how many 1933 season Hundred Pound Minors were made. I shall trawl through the chassis register to see if any examples can be positively identified.

These '33 season Hundred Pound models were fitted with the early worm and wheel steering boxes, while the 4-speed cars had the new Bishop cam box. They also had the 'short' 1932 season fluted radiator, so were to all intents and purposes built to the 1932 season spec. This was not the normal practice when changing seasons, so it must be assumed that Morris significantly over-estimated the demand for 2-seaters during 1932 and had a considerable stock of gearboxes, windscrens, stering boxes and radiators to use up.

[Ian Grace]

So I looked at the photos of about 20 1933 season 2-seaters on the chassis register, and not one of them has the 1932 season radiator fitted. Of course, they could have been replaced with the tall 1933 radiator at some point, but my suspicion is that very few 1933 Hundred Pound Minors were actually built. So the hunt is on to find one.

[plj]

Thanks Ian, it seems the more we get to know about these cars the more there is to find out.
Has anyone had the splines on the input shaft successfully repaired and if so by who?

[Ian Grace]

That's a great question. The splines on my 4-speed crash box for my McEvoy are decidedly second hand.

I believe the splines are hard welded and then re-cut using a hobbing process. That's gear machining speak I learned from my cousion who ran a gear cutting company in Sussex - sadly thirty years ago now.