Overdrive -- is it possible?

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Overdrive -- is it possible?

Post by jagnut66 »

I have long thought an overdrive unit would go nicely with my Minors but can't see it as having been discussed anywhere on here or have I missed something?
By overdrive, I do mean an overdrive unit mated to a Morris gearbox, not the Ford Type 9 option (tried it and don't like them).
Is it possible? Is there an existing period overdrive gearbox that could be (has been) made to fit the A series engines?
The electrical side would be straightforward and I would opt for a period MGB dash type switch with the identifying label ring round the outside of it (pictured below), which also has the advantage of being readily available.
But is it possible or just 'pie in the sky'?..................
Many thanks in advance for any input.
Best wishes,
MGB Overdrive switch.jpeg
MGB Overdrive switch.jpeg (53.12 KiB) Viewed 227 times
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1955 Series 2: Traveller: "Elsie May" -- On the road and enjoying her 'as is' for now but I see work ahead......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
kevin s
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Re: Overdrive -- is it possible?

Post by kevin s »

I don't think any A series engines uses overdrive but marinas had triumph derived gearboxes that used overdrives when in triumphs, so it may be possible to build something up that will bolt to the engine using off the shelf parts, your next problem will be the marina gearbox doesen't really fit inbetween a minor chassis legs, though I think there was some sort of conversion backplate at one time, finally you would amost certainly have to cut some of the floor and trans tunnel away, thats if it all even fits in front of the centre crossmember.

So my conclusion is it might just be possible but would involve a hell of a lot of work and compromises a 5 speed kit would be a lot easier.

Happy to be corrected etc.
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Re: Overdrive -- is it possible?

Post by johngrigg »

This subject is covered I the Morris Minor modification manual by Owen Burton . I think I got my copy from ESM. Short answer is possible but difficult, i.e.. certainly beyond me! Although he doesn't mention any need to modify the floor
Cheers JohnG
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Re: Overdrive -- is it possible?

Post by ManyMinors »

As others have said. Anything is possible. As I'm sure you know, overdrive was an option on the Triumph Herald/Vitesse/Spitfire as well as the MGB. Some have fitted the MGB engine and gearbox to Minors and I have had a Minor with the Spitfire 1500 engine and gearbox (heck of a lot of work and you end up with an engine certainly no better than an "A series"!). I can't think of any other route. Both these options give you a larger and heavier gearbox and a great deal of work and, in my opinion and having tried all sorts of things over the years, the best thing to do with a Morris Minor is to keep it simple and sort the gearing out that suits you best by fitting the most suitable final drive and sticking to a 4 speed gearbox.
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Re: Overdrive -- is it possible?

Post by jaekl »

The tail housing is so long and could easily include an overdrive. If one is up to some fabrication work, you could modify the third motion shaft to have third and input wheels and then a laygear but have them reversed so that the third motion shaft drives a fourth motion laygear using the third gear set and the input gear set drives a fifth motion shaft which has the speedo drive.
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Re: Overdrive -- is it possible?

Post by taupe »

I think that an overdrive unit mounted on the rear axle is easiest for the Minor....a 5 speed box will be much easier though :wink:

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Re: Overdrive -- is it possible?

Post by Bowie69 »

Marina/ ital box internals in a triumph housing with overdrive attached, engine backplate as per marina gearbox conversion and it all bolts up and works.

Triumph gears are all the wrong spacing for the minor, hence the case swap.
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Re: Overdrive -- is it possible?

Post by Edward1949 »

Interesting bit of 1950s motoring history:
By 1957 the Minor's direct competitors, the Standard 8 and the Standard 10 were listed with optional Laycock overdrive.
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