The Big End - Get in Gear - Part II

In my last article I explained how important the correct gears must be fitted to your vehicle. Is this all there is to it or is their more? Of course there is. And just for a start you must have good transfer of power through to the driven wheels. This would consist of a clutch suitable for the power range produced, capable of transfer without slipping under load. Also required would be an axle that would also complement any extra power and one that would have strong half shafts that will not break under any additional power transmitted. And last but not least wheels and tyres that will give a good footprint and acceptable unsprung weight.

With any gearbox it is desirable to have syncromesh on all gears and not as is the Morris with its crash 1st gear which unless, you are an absolute wizard in the art of doubling the clutch, in reality it can only be engaged with the vehicle stationary. The 'A' series gearbox is getting a little long in the tooth now and in many cases a reconditioned unit, which will cost in excess of £200 may well be a cobble of ancient and new parts gathered into an old casing. The fact here is that it's running on a modified sale by date ticket. It is most unsuitable for any increase of power over a standard 1098cc engine and working here with a standard Morris axle can lead to blown Interlock rings on the third motion shaft, broken lay-gears and damaged bearings The axle of course lets go frequently with broken half shafts or blown pinion gears. Not a pretty picture.

The Minor gearbox reflects the transmission technology of its day. The gearbox is a basic 4-speed unit with, as I have said, no syncromesh on first gear. Its power handling being limited to under 40bhp with any safe margin. This means it will not cope with the power of a tuned 1098cc-unit let alone a 1275cc engine with the ribbed case box, it can be fitted with the bulk-ring Midget ratios, here if built very carefully can handle up to 85 or so bhp. This specification I have tested in tarmac rallying back in the 1980's without too many problems. Of course the Midget gears, if you can get them are like Rocking Horse do-dars and you can't be sure you will get a complete set these days as many cobbles are to found.

The Morris gearbox last mod state unit came under the serial No 12G 177 unit. With the Midget/Sprite it came under the serial 12G 299. These markings can be found on the 1st motion shaft inside the bell housing and are inscribed onto the shaft. If you are lucky to find one of these even in a broken state keep it as they are in great demand.

When selecting gears and components to rebuild any of these highbred units care must be made to choose only the very best as if when fitted together, problems such as jumping out of 1st gear, 2nd and 3rd syncromesh can fail quickly and the 2nd gear stripped. A solution to all these problems could be to obtain a BMC C-AJJ 3319 spur-gear set installation this coupled with a 1275cc engine, competition clutch C-AEG 546/ makes a very strong transmission of power capable of handling in the area of 120bhp or so.

So you see choosing a good combination of compatible components capable of handling the power well outside the update engine fitted is mandatory. If this is not addressed then you must consider shares in the RAC or AA recovery services, because you are going to need them.

Now, on the other hand, all you Mod and Custom heads why not consider getting with the program and fitting a good mid range power plant together with compatible Ford gearbox, clutch drive train and back axle. Don't forget my other suggestions, which I have referred too many times over the last few years, that is after making sure the chassis and structure of the vehicle is sound, then you should also fit a better suspension and braking system. You now can see this makes sense and will culminate with a very tractable vehicle, very pleasant and fun to drive. It will also be a very useful tool in that because it is a Morris and enjoys Classic Car status it also enjoys free vehicle Tax and possible slow depreciation.

A properly modified Morris will astound many modern day vehicle drivers whose concept of this long life vehicle is sometimes coloured by derision and ridicule.

Getting in gear should, I think be considered as getting the right gear for the job intended.

©Chris Street, October 4, 2000