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MG Midget and Sprite Technical - Longer gears?

hey, just got myself a 63 midget, my fathers owned a 64 since he was 17 and is near 60 now. im wondering if theres a transmission or rear diff, that will allow for longer gears? or even allow for 1st gear syncing.


DMN Neeb

There are kits to install datsun 210 transmissions (if you can find one). That gives you a 5-speed and syncro first gear. Or... you can switch to a 3.9 rear end (assuming you have an original 4.2), but that hurts the car's acceleration.

BTW, Nice looking car.
Trevor Jessie

There is also the ford type 9 five speed box ...but its primarly a uk tranny ..but being your in canada...its possiable.

There is a usa company that sells the ford 5 speed tranny kit called quantum mechanics...somewhere along the eastern sea board...should be easy enough to google

For the datsun 210 kit, google rivergate conversions

If your the creative type... there alot of work being done with the BMW getrig 5 speed transmission... its a good fit, and good gearing ratios...but no one that im aware makes a kit for it

All that said... your looking for the whole job if you DIY, of around $2500


But if you do vary must interstate driving ...it is so worth it, not to mention the extra savings in fuel cost and the noise reduction of 3500 rpm vs 4600rpm at 75mph

Prop
Prop and the Blackhole Midget

Mmmm there are books with this stuff in. One of the largest chapters is on this very subject...

Nearly all 4 speed gearboxes have top/4th gear as 1:1 so taller/longer gearing either needs a 5 speed gearbox (with synchro on first), an overdrive (on 3rd and top) with synchro on first) or a tall rear diff ratio - if you have a 4.22 you might prefer a 3.9.
Daniel Stapleton

I changed from 4.2 to 3.9 diff and it made a far bigger difference than the "on paper" figures would suggest. Driving at 60+ is much more comfortable than with the lower ratio.
G Williams (Graeme)

this ford type 9 is it adirect bolt on? anyone have a website for sales?
DMN Neeb

id be interested in 1st gear sync, so the rear diff change isnt really what im looking for, just ANY direct bolt trannys that will give me first sync and if they can a longer gear set.
DMN Neeb

As Daniel says, the only way to get a higher output ratio with a 4 speed is to get one with an overdrive as all, in my experience, 4speeds have a 1:1 output although the intermediate ratios can be "close ratio" in certain boxes.
So you need an overdrive box which was not available for the non 1500 Midget/Sprite, though a Spitfire o/d box can be forced into a 1500 Midget, or a 5 speed, like the Ford box as mentioned earlier.
If you can live without synchro on 1st, a taller diff is by far the simplest way of getting longer gears. 3.9, 3.7 and 3.5 were available, apart from the 4.2, though the 3.5 was not fitted to a Sprite/Midget officially.I think it was fitted to a Riley 1.5 in the UK, but fits the Midget axle.
JB Anderson

no the type 9 isn't a straight swap and the first gear is still short but does have synchro, as standard the gear lever will be further back too unless you shorten the remote

the Ford box gear changing isn't as nice as a Spridget gearbox (in good condition) but as well as gaining synchro on first you get a 0.82 fifth gear

have a look in the Archives here for the various Type 9 installations and there's plenty of info on the net too as it's a popular for RWD classics and kit cars
Nigel Atkins

datsun gearbox specs:
box 4th 3rd 2nd 1st 5th Rev
60L 4-speed 1.000 1.378 2.170 3.513 3.764
60L 5-speed 1.000 1.378 2.170 3.513 0.846 3.464
60A 5-speed A 1.000 1.378 2.170 3.513 0.821 3.764
60A 5-speed B 1.000 1.320 2.170 3.513 0.821 3.764

NOTES

The 1st through 4th gears are all the same -- 4-speed and 5-speed -- except for a few 5-speeds with 3rd closer to top (larger gap from 2nd to 3rd).
For freeway driving, the 60A has a larger overdrive and so is preferable to the 60L dogleg.
First gear is the same in all 60-series boxes

Taken from http://datsun1200.com/modules/mediawiki/index.php?title=60-Series_Transmission

ive got the 60L type dogleg box and 4.22 diff ratio.. i do a lot of highway driving so i'm actually thinking about a diff ratio swap as well.....

As other people have said there are kits available from a number of sources to adapt to the A-series engine.
or do as i did and use the datsun engine that matches the gearbox...
Andy Phillips (frankenfrog)

Ford type 9 in the usa....

http://www.quantumechanics.com/qm-htm/home1.htm


Datsun 210

http://www.rivergate5speed.com/


The datsun is a direct fit, but the ford 9 is a more robust and has more options for modifications

Prop
Prop and the Blackhole Midget

Here is a link to danial stapltons book... I great read

http://www.amazon.com/gp/aw/d/1845841425/ref=mp_s_a_1_3?qid=1373333748&sr=1-3&pi=SL160_PIsitb-sticker-arrow-dp,TopRight,12,-18_SH30_OU01_AA160



Prop and the Blackhole Midget

i have the victoria british catalog and the 3.9 rear diff is 999.95$ anyone know where to get a cheaper one?
DMN Neeb

Ebay?
Dave O'Neill2

Yepp ebay or a midget breakers yard like (sportscarwarehouse.com) out of Arlenton tx.

The 3.9 was.used on the 1500s in 1978 and 1979 .... hmmm or at least thats what my god given human hat rack is telling me

Prop

Prop and the Blackhole Midget

Sorry Prop 3.7 was in late 78-80, and 3.9 started in '68 (I think)
Trevor Jessie

Thanks trevor

Brains make good pop corn...I know, I eat mine all the time...hahahaha

Gez ...where does vic brit get off with a $1000 diff for such a common garden varity size diff

Ill sell mine for $875

Prop
Prop and the Blackhole Midget

I have 3.9 and 3.7 spares here, I have shipped to USA before but it is a bit expensive.
David Smith

Well I did find a 4.22 on ebay ...ready to go

$99

If you must have the 3.9 very common diff...id say watch ebay for a couple of days...im sure one will turn up for sale

http://item.mobileweb.ebay.com/viewitem?index=0&sbk=1&nav=SEARCH&itemId=121139934794

Prop and the Blackhole Midget

3.7 diff good and mine is fine especially on back windy roads around here. I want the 5 speed to go with it so I can change up for cruising on the main roads and the 1500 will feel right at that.
But that's the expensive and hard work bit compared to the axel.
Dave Squire (1500)

David, I could be interested in those diffs if they are good, we are shipping all the time so all you'd need to do is send them to a depot in the UK. If you want to sell them email me at paulatmgpartsdotcodotnz.
Paul Walbran

Just noticed in your car pic that the sills look a bit odd... squarish at the front, and there are no jack points. Are they covers or something?

-:G:-
Gryf Ketcherside

I fitted a 3.7 diff during an axle rebuild and can recommend it for easier cruising and improved mpg.
Doug Plumb

to pricey for me now im patient and ive been wondering if any one has heard about a mazda miata component swap, fuell injected 1.8 liter?


and yea theyve been covered, im removing those and intalling new ones.
DMN Neeb

Actually the rotory b mazda has been done several times ...that might be an option

The best option if you want to do this on the cheap is a datsun A-16 swap with tranny....its almost a direct plug and play, and.it looks almost exactly like an A-series

Prop
Prop and the Blackhole Midget

This thread was discussed between 08/07/2013 and 18/07/2013

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.