Jim Clarks over/under drive

[h20hamelan]

Great day
Wondering if anyone has some info, regarding Mr Jim Clarks over/under drive unit in his elan

Said to cruise at 80

pm me if you have a few for sale, even one please

[Slowtus]

Great day
Wondering if anyone has some info, regarding Mr Jim Clarks over/under drive unit in his elan

Said to cruise at 80

pm me if you have a few for sale, even one please

Can you clarify what it is you are looking for - is it an overdrive 'box, a 5/6 speed or...just what???

For what it is worth I regularly cruised at 80 mph in my various Elans.

[h20hamelan]

I am looking for any information on over drive units.
its said Jim had one. I also would like at least one.

[Davidb]

With a 3.54:1 diff I can cruise at 80mph in my Elan - if I wish.
There is no overdrive available that will fit an Elan so far as I know and I tried a Laycock unit as fitted to most British sports cars of the time:

[rcfurse]

I am in the market for a similar solution but the constraints of the Elan chassis means that fitting an Overdrive is likely v difficult if not impossible. There are a number of threads here about 5 or 6 speed boxes.
I know that someone has fitted a 6 speed Mazda Miata/MX5 unit to a Sprint. I have seen it but I don't know how it drives or how it is fitted. I intend to find out because it is clear that there is considerable demand for a higher gear ratio solution. I do have 5.54 and 3.55 diffs fitted to two of my cars and these do allow motorway cruising but a set of Bose noise cnacelling headphones are recommended.

[69S4]

a set of Bose noise cnacelling headphones are recommended.

Too right. My iPhone noise meter was peaking at 92dB inside my Elan at 40mph on a local road recently. On a long trip we've taken to wearing earplugs.

[h20hamelan]

it has been said by a number of manufacturers that given the number (about 100) would need to be produced to make it viable.
yes, it can be fit to a nose cone.
the typical style today is to be hung off the rear of a box
so we would also need to make provisions for supporting off the chassis to allow the extra weight on the nose of the diff

quafie (no affiliation) included, said it is possible! but they aint gonna do the r-n-d

I am sure we would need to rally support in all communities to make 100 units, even if we could get 60-70 people interested pronto

[rcfurse]

If it was possible to make an overdrive that fitted inside the chassis between the gearbox and diff it could be fixed there and two shafts would be required. I will investigate. I feel sure that we could get 100 buyers at a sensible price.

[h20hamelan]

With a 3.54:1 diff I can cruise at 80mph in my Elan - if I wish.
There is no overdrive available that will fit an Elan so far as I know and I tried a Laycock unit as fitted to most British sports cars of the time:

P1060888.JPG

Thanks, and Davidb. Do you recall which unit number is on that over/under unit. As there are three sized Laycocks available.
It is much larger looking than my Volvo one which is about 6 inch diameter and 12 inch length. Still most likely not able to fit without a new differential nose.
The smallest Gear Vender would be adequate. Quafie production would be nice.
Would need to look at fitting it in there too. Though on an angle, then sliding back into place should be doable.

[Davidb]

That was a Laycock 'J' Type. Standard size.

[Davidb]

h20hamelan: This unit came from a Volvo-I used to be a service manager for Volvo-this is how big/small they are! I am not aware of a smaller Laycock unit.

[Slowtus]

Would it not be 'better' to find a 5/6 speed 'box you could fit in that small space?

I can't see any machine shop etc being able to fabricate what you would like in enough quantity to make business sense.

Or am I missing something here (I had no idea that Jim Clark had an overdrive unit in his car).

[prezoom]

Does anyone know if there is a difference in size between the OD's used on the MGB early non-synchro and full synchro gear boxes?

[JonB]

Got to say, the thought of a Laycock overdrive unit on an Elan is pretty awesome. I had a 1500 Spitfire with overdrive and it was brilliant fun. Such a shame it cannot fit the Lotus chassis.

[HAIRY]

I happily register an interested in an overdrive, were it to be developed to fit an Elan.

On an associated matter, three or four years ago MKF Engineering in East Sussex were reported in the motoring press to be developing a 5 speed cluster to fit within the Ford 2000e gearbox casting.

It may be that this was not a viable option, as The Daily Telegraph reported in August 2018 an illegal gun factory had been found on the MKF premises!

Should it be assumed that all Elan gearbox development work has stopped at MKF?

Does anyone have an information on other locations of the development of a 5 speed Ford 2000e gearbox?