The Problems of Building a Lotus Eleven

By Andrew Denton - Auckland NZ - <>
From Lotus Internet List - Aug 19, 1998

It was never intended as a three year project it just happened that I had to include building a Lotus 7 for my sons twenty first as a priority, and the other reason was that whilst there were plenty of clear photographs to retain originality it is necessary to source original components where possible.

For more years than I can remember I have craved for what must be described as "the almost perfect shape" in sports racing cars, and when the Eleven was introduced in 1956 this was the ultimate. The only draw back to owning an original is the currentNZ$90.000 price tag. Having realized that I was not going to get this for selling the wife and kids then the only alternative was to build one from scratch using a copy of the original plans, a dog-eared copy of which appears in Dennis Ortenbergers book on the Eleven.

The easy part is the basis chassis which consists mainly of 1"and ¾" x18swg square and round ERW tubing. The finished article is very reminiscent of a Lotus 7 with the front widened. The transmission tunnel and the floor act as stressed panels. The side tubs are totally fabricated in 18swg alloy sheeting and do not have any tubular members. The only problem is that the original drawings are a little sketchy and some dimensions are either left out or unreadable so the only answer is to redraw them and then the missed ones become more obvious.

I purchased the three bodyshell moldings (i.e. bonnet, scuttle and the tail) which were taken from an original car complete with nearside damage and from there on you are on your own.

Front suspension
Mark1 Elevens run a Ford Popular beam axle cut in the middle and rubber bushed. This gives a wildly negative camber necessitating heating of the beam and resetting. I made up a jig so that both sides are the same and this gave a datum from which to work. This is the only way that camber can be adjusted. The Ford Pop radius arms which were originally joined in the middle with a ball and socket on the chassis are cut, tapped 11/16 UNF and a Ford Pilot track rod end screwed in. This then attaches to the chassis at the main bulkhead. The mounting for the coil over shock is a special machined pin straddling the beam and the radius arm.

Rear Suspension
I wasn't game to try and produce a De Dion as the whole thing was taking too long and anyway the club model came out with a live rear axle. This is an A30 located by 4 radius arms attached to the brake backplates, the offside lower having a very short "Panhard" rod attaching to the chassis at the transmission tunnel. Coil overs attach to the axle from the original BMC lever shock absorber anchorages. Both the front and rear shocks are standard units made into adjustable units by Mig welding a running thread onto the outside.

Front brakes are disc using a ford Escort Mk1 hub machined to accept the Ford Pop hub bearings. The Ford Pop stub axles are retained and the caliper is attached by a special alloy casting. This took weeks to work out as the photos were not too clear I made the patterns and had them cast and them machined them on my lathe.

Rear brakes are Morris Minor in order to run hydraulic. The handbrake located under the dash was a mixture with the cable running through the side tub.

Twin Girling master cylinders are used with a balance bar and remote reservoir.

Very early in the piece it looked as if I was going to have to run a BMC A Series motor until I received a call from a person in Whangaparoa After quizzing me for 15 minutes he announced that he had a 750 FWMC Coventry Climax engine under the house that he was not sure that he wanted to sell. After an inspection of the car I persuaded him that it would go to a good home and we did the deal. The engine came without a flywheel and I decided that as I was using a BMC gearbox I would use a BMC ring gear.

When visiting the local metal merchants I tripped over a 10" bar of alloy which I had a I" cut taken off. This just fits in my Myford lathe and I machined a flywheel from it. This really allows the engine to rev freely and sounds great when you shut down and it stops instantly. Just like F1. Mating the engine to the gearbox was a drama on its own and I ended up cutting an alloy plate out with a Black and Decker jig saw using copious quantities of lubricant.

The Climax inlet manifold is altered to allow the use of twin semi downdraught 1.25" SU carbs and the exhaust I bent up to resonate a 5,500RPM. There is not a lot of room under the car (max 4" ground clearance) but the nearside tub is made with a step to allow for the muffler so only a small cherry bomb is used.

Rather than wreck a Sprite close ratio box first up I carried out all the mods needed on a Morris 1000 box first. This includes extending the input shaft to reach the clutch. With the limited power offered by the Climax I considered that cutting, sleeving, welding and reheat treating the shaft would suffice. This has worked and the same mods have been carried out on a Sprite close ratio box which is now in the car. Original cars ran an MGA box but this was not available to me at the time. The best bit is that one person can just about carry the engine and gearbox assembly and installing it in the car does not require a block and tackle.

Sundry parts
The radiator, petrol tank and water header tank are made to the same dimensions and are mounted as original. The petrol tank is alloy and is mounted under the scuttle in front of the "passenger". The fact that there is no seat belt or seat for the passenger is irrelevant.

The wheels are wires using ex MGA wheels size 4.00x15. The tyres are 4.50x15 Michelin as used on the Citroen Diane.

I used original gauges and switches oddly enough some are still in production such as the A30 dash mounted indicator switch which I found at Lucas. The ignition and head light switch is Morris 8.

Painting I carried out in enamel. (did they have two pot paint in 1956?) with the windscreen and head light covers molded in perspex. The all up finished weight is 850 lbs.

Whilst road registered it is a pig to drive on the road but comes alive on Whenuapai airfield when you can let the tail hang out. What is very noticeable is that at the end of the straight the body shape does not give any wind braking and if you do loose the back end it scrubs speed of so quick due to the low weight.

The next project which is well under way is a Lotus Elan series 4!!!!!!