Gearbox, Clutch and Propshaft
Julia (my wife) agreed to me rebuilding the Elan with one proviso - That she would be able to actually drive it. In its previous incarnation the four paddle clutch was so stiff she had to pull on the steering wheel to push the pedal down and she is no wimp!
I spent many an evening surfing the net and many a day talking to clutch suppliers and racers. It finally dawned on me that what I was looking for wasn't actually available so I decided to get the best clutch for the job (in my opinion) and sort out the pressure issue with slave/master cylinder sizes and pedal ratio.
I settled on an Alcon 7.25" twin cerametallic plate unit and slave cylinder.
With regard to the flywheel, we settled on the steel Cosworth 4x4 version. As we will be doing many drag starts a heavier flywheel will be advantageous.
On discussing drag starts with Graham Hathaway (who knows a bit about standing starts as he used to hold the in an RS200) and Bob Buck, my suspension guru, Graham said that I need to be able to release the clutch 'as quickly as possible slowly'.
I liken this to the difference between on/off and dimmer light switches. The on/off switch is either off or fully on. The dimmer switch, however, brings in the power gradually, no matter how quickly you turn the knob.
This is what he wanted to achieve manually with deft control of the clutch pedal. Whilst discussing this with Graham and Bob we came to the conclusion that we should be able to do this mechanically and looked into how we could make a two way valve do the job.
I went away to do some reseach and came up with an industrial valve designed specifically to do excatly what we want. It doesn't restrict fluid going to the clutch release bearing but you can control the speed at which it returns to the master cylinder by the turning of the knob.
During my research I discoved that some Japanese cars are fitted with a simply restrictor as standard and a valve is available but has to be removed and shimmed in order to adjust it. My solution is infinitely adjustable from the comfort of the driver's seat :-)
If interested, this item is available in
Adjustable 2-way valve.
Controlling the speed of the clutch fluid return to the master cylinder.
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By adjusting this knob on the dash.
Gearbox choice, initially, was simple. A T5 Ford unit. However, the gear lever is situated at the end of the tailshaft, as opposed to the Elan box where it's at the front.
More research discovered that the T5 fitted to the TVR Speed Six has the gear lever in the same place as the Elan box. Bernie at Competition Gearboxes had just such a box so a quick trip up north and an exchange was done with a T5 I already had plus some drinking vouchers in his direction.
Gearbox sorted, or so I thought.
Tremec T5 box from a TVR Speed Six
Although the 5 speed T5 box was an improvment on the original Elan 4 speed unit and would handle the power, I secretly hankered after a 6 speed sequential box. The problem, however, was that there was very little room to fit one withn the confines of the chassis. I had downloaded many CAD drawings of various boxes buy none fitted.
Everything changed when I visited The Classis Ford Show at Santa Pod. Elite Transmissions had a stand and were showcasing their IL300 box, which appeared to be thinner than the other boxes I had looked at. A long chat with Rob Swift ended with him offering to send me a casing to see if it would fit.
Later that week the casing arrived and I offered it up to the chassis and it fitted!......sort of.
Although it fitted between the chassis frame, it was an interferance fit which wouldn't work. A little bit of thought and I reckoned that it would work if we shortened the bellhousing by 30mm. A chat to Rob confirmed that they could make a shorter main shaft and cut 30mm out of the bellhousing.
IL300 casing and Tremec T5
With engine bolted in and gearbox pulled forward to clear chassis, this is the space left for the bellhusing.
So, a deal was made and a few weeks later I took delivery of a modifed IL300 box and a shortened bellhousing.
Although the shortened bellhousing was well done, it was a bit overweight. I took to a friend, Tony, engineering company in Latchingdon (Reef Engineering) and they took a chunk of weight out of the gearbox mounting flange.
Shortened bellhousing as supplied by Elite Transmissions and as modified by Reef Engineering
IL300 complete with gear lever and clutch release bearing.
To see the Pneumatic gear change system, go to and
Next, I had to make a gearbox support bracket, as the mounting points on this box were different to the old box and not even in the same location.
Kept it simple, as I always try to do. 1/2" aluminium plate, two angled brackets and four bobbin rubber mounts. With the roll cage stiffening the chassis i could possibly get away with solid mounts (the engine is already solid) but have decided, for now, to stick with a little bit of give.
Ignore how the angle brackets are fitted, the right hand one is on backwards.
Dry fit of mounting. Holes about to be drilled in chassis flanges and captive nut welded in place.
These two photos illustrate just how tight the gearbox is to the chassis. With 20/20 hindsight I would have made the bellhousing a another 20mm shorter, thereby pulling the gearbox further forward and increasing clearances.
However, as with most things on this build, my plans changed when I decided to go down the flappy paddle route, negating the requirement for a remote lever. Another item for the 'For Sale' section :-)
Having sorted the gear lever problem by using the TVR box, it was back again as the Elite box has a rear lever.
My first idea was to make a remote lever, so this I did and was quite pleased with the result. With the engine mounted solidly there wilbe very little box movement so I reckoned that Icould get away with mounting the remote lever on the chassis.
Nothing trick about the propshaft, apart from the diff flange being lightened. This was made by Bailey Motors to my spec.