Morris Minor Owners Club

Hi guys,

Can anyone tell me what would be the best differential ratio for running with a 5 speed gearbox?

What is anyone running with this set up?

Regards

John

I'd suggest you go with what you have now then change it if you feel the need.

Sounds like a good plan to me - unless you have the 5.33 ratio at the moment..... It also all depends on what power you have to lug the car along. With a diesel engine for example - a 3.7 would be required!

John,

What engine spec, gearbox and diff ratio do you have now?

I have a 3.9 diff with a Toyota 5-spd box that gives 20.6 mph/1000 rpm in 5th. With a well modified 1380 this gives a very easy motorway gearing and little need to change down for hills or overtaking.

It depends on what engine you have but as 5th gear will be an overdrive then you will probably not need to change the diff.

The engine would be a +20thou overbored 1098 cc, with a 1 1/2" carb, either a HS4 or HIF 38, and either a Mini exhaust manifold or an LCB (haven't decided quite yet). I believe the diff would be a standard 4.22 1098 one, unless someone in the past has swopped it over for a lower ratio one at an earlier time in the cars history. I have a 3.9 diff, but was hopefully going to use this on a 1275cc Hot Rod project.

Regards

John

we seem to have identical vehicles.

i too have a 1098 + 20 thou with a standard cam and a 1 1/2 inch HS4 carb.

recently fitted a five speed myself, (before that i had a 4 speed and 3.9 diff) so when i fitted the 5 speed i kept the 3.9 in. i didnt really get along with it, much too 'long' geared especially in fifth, so i changed back to the 4.2 it had originally. very happy with the performance.

i too have a 1275 project which that 3.9 will be saved for!

The 5 speed box was going to be fitted to a '56 Series II, but after some negative comments, it looks as though the '56 will be fitted with a midget box, converted to fit the Series II floorpan. Well, it will be after sorting out the 'box and engine on the 4 door and funds allow.