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Author Topic: Lotus Cortina and Escorts  (Read 6111 times)

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Offline Tony

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Lotus Cortina and Escorts
« on: September 08, 2006, 22:09:05 PM »

The Lotus Cortina's

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The Lotus-Cortina, the car sometimes known as 'the original fast Ford', appeared in January 1963. There was an increasing demand for sporty cars, and in the USA the relationship between racing success and sales success was being realised. In the early '60s Ford implemented a worldwide policy of 'Total Performance', and each Ford division was left to its own devices. The Lotus-Cortina was the brainchild of the Ford of Britain Public Affairs chief at the time, Walter Hayes. He went on to take part in the founding of the Ford Advanced Vehicle Operation (FAVO), which was later responsible for such efforts as the GT40 and the Escort RS models. The Lotus-Cortina was conceived and developed rapidly, as anyone who owned one and had the rear suspension collapse will tell you.

So how did Lotus fit into the scheme of things? At the time Lotus were developing a twin-cam engine based on the bottom end of Ford's 1499cc powerplant for their Elan, and Hayes knew Lotus boss Colin Chapman personally. Hayes put forward the proposal to Chapman of assembling 1000 Cortinas with the Lotus-Ford engine, so the car could be raced and rallied as a Group 2 production car. Group 1 cars had to be virtually the same as the average family car, but Group 2's could have modified engines, steering and suspension. The thumbs-up was given, and the Type 28 Lotus was born, eventually to be called 'Cortina developed by Lotus' by Ford, and the 'Lotus-Cortina' by the rest of us. You could get yourself one for £1100.

The car succeeded magnificently in lifting Ford's performance image, with its rapid performance and taut and grippy handling making it a great success on both race tracks and rally courses. But it didn't do so much for building a reputation as a producer of reliable cars...
The Mk.I Lotus-Cortina was replaced by the all-round less tempestuous Mk.II in March '67, after 2894 were produced. Of these, it is estimated that about 1300 had the first suspension type.

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 Unlike the Mk.II Lotus-Cortinas, the Mk.I Lotus-Cortinas were developed and assembled by Lotus at their Cheshunt factory in North London. Lotus started with two-door sedan shells, to which was added lightweight alloy doors, bonnet, and boot lid, to aid racing success. To the boot area over the wheel arches tubular stiffening braces were added, to suit Lotus' rear suspension, and the boot also became the new home for the battery. The spare was also fitted to the boot floor, rather than in the wheel well. The alloy panels became optional equipment from October '64, when Ford gave the Cortina range an updating, and so the Lotus-Cortina picked up the same changes, including the wider grille, and a revised dash with flow-through 'Aeroflow' ventilation and the accompanying air outlets in the C-pillar. The bracing in the boot was discontinued in June 1965 with change to the more conventional Ford rear suspension.

And of course it would be remiss of me to say that all these cars were turned out in Ermine White with Lotus-green (Sherwood Green) striping and rear panel. The other feature of the paint job that set it apart from the standard Cortinas was the lack of rust protection measures, meaning fun and games for restorers down the track. Lotus-Cortinas also sport small 'bumperettes' up the front, and Lotus badges on the rear quarter panels and on the blacked-out front grille.

Engine

The Lotus-Cortina story the real interest is the donk. As mentioned, it was based on the five-bearing bottom end Cortina engine, and used many Ford parts, but it sure doesn't look much like the standard Cortina engines. The conversion was designed for Lotus by Harry Mundy. Initial designs were based on Ford's 1340cc three-bearing block as used in the Anglia Classic 109E, but the 1499cc (116E) was decided on for the Elan, which was bored out 82.55mm to give 1558cc, to suit the 1600cc competition class limit. Retained from the 116E was the crankshaft, connecting rods, and pistons. To this was added a Lotus-designed camshaft drive and aluminium cylinder head assembly.

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The twin-cam cylinder head used valves operated directly from the cam lobes by inverted bucket tappets enclosing coil springs, with two valves per cylinder. The head was a crossflow design, with the inlet manifolds being part of the same casting. Technically this was actually a three-camshaft engine, as the original Ford camshaft was retained to drive the oil pump and distributor, which resulted in a near impossible to reach distributor. Camshaft drive was by a long single-stage roller chain.

The juice was slurped in through two touchy horizontal double-barrel Weber 40DCOE carbies, and the engine was also fitted with a 6500rpm rev limiter, so the standard Ford bits wouldn't pack it in. The official Lotus performance figures were 105bhp at 5500rpm, with maimum torque of 108lb ft at 4000rpm. It's generally held that these figures are a bit hopeful (90bhp is quoted for the same engine in the Lotus Elan), but nevertheless, the Lotus-Cortina was and is renowned for its poke. The figures don't sound too shabby even now - top speed of 105mph, 0-60mph in just under 10 seconds, nearly 50mph in 1st, 70mph in 2nd, and 90mph in 3rd.

Gearbox

Again Lotus started with standard Ford equipment, using bits and pieces from Cortinas and Corsairs, and the Lotus-Cortinas sported a four-speed floor shifter, with synchro on all four gears, and a hypoid bevel design rear axle. Like many bits of the Lotus-Cortinas, the gearboxes got less technical but more durable as they went on, and the gearboxes in particular seemed to be in a permanent state of change. The Lotus-Cortina was born with the gearbox developed for the Lotus Elan, with rallying in mind. This gearbox featured very close gear ratios (to suit the lighter Elan), a diaphragm spring clutch, alloy case and clutch housing, and a remote control gearchange. Over the lifetime of the Mk.I Lotus-Cortina all these features disappeared or became optional. In July '64 the alloy parts were made optional extras, and the Elan gearbox ratios were made optional in favour of a modified GT gearbox featuring a higher 2nd gear ratio, the Elan ratios not proving to be too flash for road use. In October '65 the gearbox ratios were changed again in favour of the Corsiar 2000E gearbox, which came to be used in the GT and in the Escort Twin-Cam.

Suspension

The first Lotus-Cortinas had a single-piece propeller shaft, and a back axle with coil springs and located by radius arms and an A-bracket linked to a light alloy differential housing, and used a 3.90:1 final drive ratio. This setup placed excessive load on the differential housing, and the retaining bolts tended to come loose, which caused oil to drain out of the axle, destroying the diff, and with the leaking oil doing similar to the suspension bushes, causing surprise collapses. It also transmitted mysterious thumps and clunks into the cabin. In July '64 the light alloy diff housing became optional, and a two-piece propeller shaft was introduced. In June '65 the entire rear suspension was replaced by the setup used in the Cortina and Corsair GTs, half-elliptic leaf springs and twin radius arms. This setup proved to be far more durable, and nobody really noticed the difference.

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Up the front was a simple McPherson strut suspension, and an anti-roll bar. The whole car was much lower than any other Cortina. Like the GT, the Lotus-Cortina had 5.5" wheel rims and Girling 9.5" front disc brakes and 9" rear drums. A vacuum booster was fitted. Recirculating ball steering was used, as on all other Cortinas.

Trim

The first Lotus-Cortinas were pretty sparse inside, as they were designed with racing in mind. The dash used was to appear later in the '64 GT, and featured only basic instrumentation, with the exception of the tachometer. A centre console hid the remote-control gear change, and a Lotus wood-rimmed steering wheel was used. All trim and carpet was in black only.
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The update that was introduced to the Cortina range in October '64 brought with it a new dash, with a full set of instruments, and that 'Aeroflow' ventilation. The dash was particularly good looking, with the instruments set in a simple brushed aluminium panel. The seat and door trims were updated.
« Last Edit: January 04, 2012, 13:06:01 PM by Dave »



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Offline Tony

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Re: Lotus Cortina and Escorts
« Reply #1 on: September 08, 2006, 22:55:27 PM »

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The Lotus-powered Escort Twin Cam was conceived and developed by Ford's Boreham based competitions department during 1967 and unleashed on an unsuspecting public during January 1968. It went on to achieve many international race and rally victories during its short production life. The car's first international win was on the 1968 Circuit of Ireland Rally when driven by a certain Roger Albert Clark.

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The Twin Cam owed much of its ancestry to the Mk1 and Mk2 Lotus Cortinas, in that they all shared many common mechanical components. Although its production might seem a logical step to many of us now, the route to producing the Escort Twin Cam was quite tortuous and would not have taken place without the dedication of some key Ford staff.

Near the end of 1966, some very early hand-built standard Escorts were being track tested at Boreham. They were spotted by Henry Taylor (Ford's Competitions Manager) and his Chief Mechanic Bill Meade and it was rumoured that on seeing the cars, Meade uttered the immortal words "Blimey, one of those things would go like hell with a Twin Cam engine in it!" Taylor enthusiastically agreed.

What happened next was essentially a race against time and Ford's higher authority. Henry Taylor knew he wanted a car that was faster and lighter than a Lotus Cortina but that it would be a nightmare to follow all the company procedures to introduce a performance Escort in the timeframes they had available. So in early 1967, after some hasty planning, Taylor and Ford's Public Relations Officer, Walter Hayes managed to convince the Board of Directors that their concept would work. The chiefs agreed that a few prototypes could be built.

Enter the next problem - all the tooling had already been frozen for production of the new Escort, so a standard production Escort shell was all the Twin Cam developers could use. In actual fact, during a Spring weekend in 1967, the only 'vehicle' they could lay their hands on was a plastic mock-up shell. Nevertheless, the candle was burnt at both ends to try and cram in all the Lotus Cortina mechanicals. Yes, you've guessed it - at first, the jigsaw wouldn't fit together! A few of the problems encountered were as follows...

The wide Lotus DOHC cylinder head with its twin sidedraught Weber carburettors fouled the offside inner wing, so offset engine mountings were used to push the nose of the engine towards the nearside of the car. The rear carburettor also fouled the brake master cylinder, so this was relocated inside the front bulkhead along with the clutch master cylinder. There was also insufficient space to locate both the battery and the brake servo in the engine bay so the battery was relegated to the nearside of the boot well (as per the Mk1 Lotus Cortina). The remote brake servo was then mounted where any standard Escort's battery would be. Moving the battery to the boot meant that the spare wheel was bolted flat to the boot floor instead of being housed in the standard Escort's upright position.

The "2000E" gearbox and its bellhousing (borrowed from the Ford Corsair) were made to fit by literally adjusting the transmission tunnel with a few hefty blows from a lump hammer! The rear axle from the Lotus Cortina was transplanted completely including the latter's radius arms to allow positive axle location. In short, by the end of that busy weekend, the mechanics at Boreham had solved all the major problems. Now their manager had to work on Ford's production staff to convince them to build the Twin Cam alongside Halewood's main Escort production line.

The authorities at Halewood eventually agreed to produce Twin Cam bodyshells (known as Type 49) at their factory. Essentially the Type 49 shell was a strengthened and slightly modified Escort GT (Type 48) shell. At a strategic point on the production line, the modified Type 49 shells were whisked off to a side workshop where dedicated staff turned them into Twin Cams. The all-important Lotus engines were shipped in from the Lotus plant at Hethel in Norfolk.

For the vast majority of its life, the Twin Cam was only available in White. Also, to simplify production and to keep costs down, Twin Cams were fitted with similar interiors to the Escort GT. The early cars were also fitted with rectangular headlamps as the product planners insisted on the Twin Cam having commonality with other "top of the range" Escort models - it didn't matter that all the rally drivers hated them as their performance was pitiful when compared to the cheaper Escorts' round units!

To ensure that the Twin Cam was available to "works" and other works-supported rally teams as soon as possible, the first 25 models were assembled at Boreham in early 1968. Mainstream production then transferred to Halewood during Spring 1968, with the car's official launch price being £1,162.78. The Twin Cam's specification only altered in detail during its short lifetime. Apart from the headlamp change, only minor revisions took place to the interior trim, although a potential owner could specify competitions-developed items at extra cost.

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« Last Edit: January 04, 2012, 13:07:46 PM by Dave »

the 24v xr4i auto-0 to 60 in 6.71 secs

Marty

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Re: Lotus Cortina and Escorts
« Reply #2 on: January 08, 2008, 15:21:10 PM »
I have a Lotus Cortina (MK2) workshop manual should anyone need any info.

Simon 3 door

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Re: Lotus Cortina and Escorts
« Reply #3 on: January 08, 2008, 16:13:45 PM »
Quote from: Marty
I have a Lotus Cortina (MK2) workshop manual should anyone need any info.

Surely you mean a Cortina Lotus manual?? LOL it's a Mk 2 hence it was called a Cortina Lotus then, not a Lotus Cortina... minor detail! My friend used to own one VCV 184H not sure if its still about but it had been heavily tweeked by Burtons and used to rev beyond 8000 RPM!

glyn

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Re: Lotus Cortina and Escorts
« Reply #4 on: January 09, 2008, 13:40:01 PM »
had a 66 model in 1970  should have kept it swapped it for a cooper s good at the time cortina was the better by far but s was good fun...glyn