Lotus Cortina Mk1: A history Part 1

PART 1

Given its Cortina origins, the first Lotus-Cortina was quite exotic for its time. As a road car, it kept dealers busy with rear axle replacements and owners had to be vigilant with the easily-damaged light alloy panels and a tall first gear that was hard on clutches. (Image: nickwhalesportscarsdirect.co.uk)

Lotus-Cortina Mk I: The Extraordinary Came at a Cost

The Lotus-Cortina was vital in validating yet another conservative British Ford against adventurous new rivals, a role especially important in Australia. From an era before designer labels were spread around like rubber stamps on generic products, the Lotus-Cortina was a genuine Lotus based on Ford’s ground-breaking Cortina unitary design of 1962.

Designated Type 28, it was book ended by the Type 27 Formula Junior open wheeler and Type 29, the first Lotus Indianapolis racer. Lotus was in the fast lane and fast outgrowing its cottage industry status.

Two critical developments opened the door for the Lotus-Cortina. A new Ford-based twin-cam engine for the Type 26 Lotus Elan was an opportunity waiting to be exploited.

After Ford’s Dagenham division cheekily rejected the US-developed front drive Cardinal, Ford and Lotus weight-loss priorities were suddenly compatible. To match the Cardinal’s weight, packaging and cost targets in a rear drive equivalent, Ford applied state-of-the-art aerospace stress-analysis to the Cortina.

Ford Cortina Mk I

The advances of the Cortina Mk I were not fully understood in Australia on release but the GT and the Lotus Cortina soon changed that.

Ford said no to Colin Chapman’s suggestion of building a steel-bodied Lotus Elan only to give Lotus the job of adding the Elan’s best bits to the Cortina. Diana Rigg drove an Elan in The Avengers similar to this early example owned by the writer in the 1970s. Ford and the Cortina were winners by association. Although Lotus was not quite in Ferrari territory, it was the cheeky and clever young challenger.

Two Ford UK personnel in particular and their contributions were even more relevant to the Lotus-Cortina.

Dennis Roberts was Ford’s secret weapon. Australian Don Ward, after rising to Chief Body Engineer at Ford UK, had set up a pioneering structures laboratory in the late 1950s anticipating the trend towards lightweight unitary body shells.

Roberts in the meantime had left Ford for the aerospace industry then returned as an expert in the latest stress-engineering principles and calculations in supersonic aircraft and helicopters. It was a field growing at a frenetic pace after the embarrassing stress failures of the pioneering Comet IV jetliner.

On Roberts’ return to Ford, Ward gave him the job of heading up the new lab. Roberts’ work on a new lightweight shell for the Cortina was the first opportunity to validate Ward’s vision. Another Australian Ford engineer from Geelong had been sent over to work with Roberts to anticipate any durability problems. Ford would ultimately incorporate the Australian improvements in all Cortina shells leading to the Cortina’s global rally successes.

Because there was not a surplus piece of metal anywhere in the Cortina, Colin Chapman’s early modifications to the Lotus Cortina generated their share of problems.

This explains the two distinct versions of the Mk I Lotus Cortina. The earlier version with extra Lotus parts is more sought-after as a collector’s item. The second version with more mainstream Ford parts was no less effective and far more durable.

The Lotus Type 26 Elan Solution

The 105E or Kent engine, Dagenham’s new overhead valve inline four, had become a favourite with tuners and racing teams alike. Under the bonnet of the new reverse-slope rear window Anglia, it was no less admired in Australia. Colin Chapman first saw the potential of adding a twin-cam head to the 1340cc 109E Consul Classic engine then the 116E 1498cc version with its five bearing crankshaft.

Normal Lotus-Cortina rocker covers were blue while the green covers in this case signify a very rare Special Equipment version. Note the position of the brake booster that had to be moved in later cars for left hand drive. The distributor hidden under the carburettors made replacing the points and setting the timing a real challenge, even more so on the Elan. (Image: nickwhalesportscarsdirect.co.uk)

The aluminium Lotus twin-cam head was designed to fit the stock Ford block leaving the original camshaft in place to drive the distributor, fuel and oil pumps. Designed to neatly slot under the 1.5-litre European FIA class for the Elan, it was changed at the last minute after the FIA lifted the limit to 1.6-litres.

Although the head design was originally defined by ex-Coventry Climax man Harry Mundy, Lotus commissioned Cosworth to rework it for Ford blocks which had their bores increased to deliver 1558cc. The first Elan deliveries were then recalled to have their 1.5-litre engines swapped at no cost. The engine was assembled by J.A. Preswitch (JAP) who combined the new heads with specially selected Ford blocks that would tolerate the increase in bore.

Apart from this twin-cam engine and its special close-ratio Ford gearbox, the Elan also featured a race-bred independent rear suspension that exploited pioneering coil over shock struts and wide A-arms with double-jointed driveshafts.

Chapman had originally offered the Elan to Ford as a steel body sports car for the Ford network. Although Ford wasn’t interested in the niche sports car business, the proposal had opened the door.

In a classic case of Chapman getting what he needed, not what he wanted, Lotus was not only given a joint venture model but was left with a new factory to build it in. An onsite Ford staffer was assigned to Lotus to fast track the production processes, invaluable for Chapman’s wider transition to a volume manufacturer.

Colin Chapman hated the Cortina’s rear leaf springs and insisted on replacing them with coil over shock units that fed rear axle loads into the shock mounts with disastrous results. It led to a tidy little earner for Lotus adding braces forward into the cabin and rearwards into the boot, on both sides of the rear wheel arches. (Image: nickwhalesportscarsdirect.co.uk)

The axle on the left with six mounting points is the earlier Lotus design with an A-frame that channelled severe twisting and locating forces into the diff and its mounting points, which the taller Cortina body amplified. The later Ford design spread loads over eight mounting points and was equally effective without the breakages. (Image: pixelmatic.com.au)

The Elan and the new Lotus-Cortina assembly and development facility would remain Lotus property. The lift in manufacturing expertise and economies of scale would later allow Lotus to function at another level as an independent road and race car manufacturer.

Under Ford’s global Total Performance mantra, Dagenham had to quickly find a winner more applicable to its own market requirements than the Falcons and Galaxies competing in Europe. There was also a valid concern that the Cortina was looking old school against the innovation of the Mini, Volkswagen and Renault.

After Ford and Lotus combined the Elan’s performance parts with a special Cortina shell with aluminium panels, a premium-level Cortina could be positioned as a cut-price Alfa Romeo alternative for the European market. It was then a relatively short but not always simple step to develop it into a dominating force in saloon car racing.

Lotus was then given the job of building the cars so Ford could concentrate on its core business which would soon involve meeting exploding global Cortina demand!

The Lotus Formula I and Indianapolis association then added all the credibility Ford would need for its base Cortina. Everyday Cortina owners could then quietly bask in the glow knowing there was nothing under their bonnets to confound local workshops or DIY repairers, still a big consideration in 1962.

The Lotus-Cortina was a win-win for all parties before it even turned a wheel!

Adding to the expensive double-handling but today’s exclusivity in the first Lotus Cortinas was the replacement of the instrument panel with a special item. Even the seats had to be re-shaped and re-trimmed specially for the Lotus-Cortina. (Image: nickwhalesportscarsdirect.co.uk)

Because the Cortina faced new Japanese entries as well as its British and European rivals in Australia, the Cortina was in even greater danger of being dismissed as a stretched Anglia or worse, a British version of the frail first US Falcon. Although the Lotus-Cortina could never be sold in Australia at a competitive price under strict local import restrictions, it had an important role to play in the hands of privateers.

As soon as the same drivetrain could be combined with local Escort production, it was sold locally. However, specialist Lotus input in parts and assembly made that process impossible for the Mk I Cortina. This forced Ford Australia to develop its own Cortina GT program that ultimately drew on several Lotus-Cortina developments while the Lotus-Cortina and Lotus Elan weaved their magic in the hands of privateers.

The First Lotus-Cortina Mk I

After handing the whole Lotus-Cortina project to Lotus, Ford could distance itself if it fell over. Because Ford was only supplying unfinished two-door Cortina shells, it was not exposed to anywhere near the same problem areas if it had undertaken the Elan sports car project. After the Elan continued as a Lotus, Ford’s rejection of the Elan project added more exotic credentials to the Cortina than if Ford had produced the Elan.

Although the Chapman association was the source of everything brilliant about the Lotus-Cortina, it was also fraught with the usual Chapman frailties. As expected, he approached the Cortina as an overweight production car that needed to be lightened. Except the Cortina was already the product of a far more expert and complete weight loss program than anything undertaken by Lotus.

The Cortina rear section was carefully designed so that the stresses fed into the body by the rear axle were carefully spread over the front and rear leaf spring hangers and centre shock mount. Chapman’s attempts to replace the stock live axle with a complete Elan independent rear end were blocked by Ford keen to protect the credibility of the production Cortina. Chapman then replicated his Lotus Seven clubman rear end under the rear of the Cortina with initially disastrous results.

Adding Lotus gauges to the later Cortina GT dash and using off-the-shelf Cortina GT seats trimmed in black contributed to the big savings achieved in later examples. Note the dash was now painted black, not white as in earlier cars. (Image: peter.bryan.org.nz)

Because the Seven had no structure behind the rear axle, the Cortina’s leaf springs were replaced by coil over shock units that fed rear axle loads into the shock mounts next to the rear wheel arches. Trailing arms were bolted up to the front spring hangers and a big A-frame was mounted under the diff and attached to the body under the rear seat. To bring the unsprung weight back to what it was, the diff housing was made from aluminium.

The results were predictable. The saloon body’s higher centre of gravity added stresses not seen in the low slung Lotus Seven. Rear panels distorted as the coil springs punched rear axle loads into the body and the A-frame stresses on the diff generated ongoing oil leaks and diff and axle failures.

Although other driveline parts were made of aluminium and the doors, bonnet and boot were skinned in aluminium, the Lotus modifications actually increased Cortina weight.

The main culprits included extra bracing that extended in both directions: rearwards in the boot and forwards into the rear passenger compartment behind the side trim so that it could spread the rear axle loads over the length of the deleted leaf springs. The extra bits that came with the twin-cam head, twin Webers and brake booster added their share. The clutch and tail shaft were both lifted in diameter.

Steel wheels widened to a chubby five and a half inches with inset hubcaps may have defined a new street fashion but added weight compared to racing alloys which were not yet trustworthy on a road car in 1962.

Brakes were the GT’s front discs and the larger Classic’s rear drums. Both had harder compounds that required the booster, located in early cars at the back of the engine bay. A big drop in ride height was matched by new forged steel lower control arms at the front to reduce negative camber and lighten steering loads. A bulge was let into the boot floor to allow clearance for the diff at the lower road height.

Although the later Lotus-Cortina Mk I had much less Lotus input, it was a much easier car to live with. The Ford rear axle design cut warranty claims dramatically which earlier owners were left to carry after the warranty ran out. Its new flow-through ventilation improved aerodynamics as it allowed drivers to travel with windows closed. (Image: americancars.com)

The battery was moved to the boot RHS rear corner, cutting capacity further after the rear bracing prompted the spare wheel to be shifted flat across the boot floor.

The stock Cortina’s basic strip gauges and plastic steering wheel were swapped for a proper Lotus instrument pack similar to the Elan’s and alloy-spoke wood rim wheel, also shared with the Elan. The stock dash trim and body colour cabin finish stayed.

The flat Cortina seats were upgraded to plump buckets with side contours on the same frames, divided by a centre armrest/storage bin and centre console which housed the remote gear shift. This dictated the bench seat Cortina’s umbrella handbrake. All added weight but were useful for racing and critical to the upper level presentation necessary for vital homologation road car sales.

Lotus discipline was restored by the rubber floor mats and the token front bumperettes plundered from the Anglia delivery van. All were based on a white two-door Cortina 1200 shell with its Consul bonnet badge, opening quarter vents and rear side glass.

Painted by Ford, it was then adorned by the Team Lotus green flash with its outline dependent on who was doing the painting, and blacked-out grille mesh, a livery determined by Colin Chapman himself. It arguably established the appearance agenda for every special version of a production sedan from that point.

The engine bay of later Lotus-Cortina Mk I examples had the brake booster moved to the front of the engine bay ready for LHD models. This one features the blue rocker covers of the base engine specification. (Image: Brian Snelson, Wikimedia.org)

Although several lower weight figures were claimed, the most consistent unladen kerb weight quoted was 16.2cwt/810kg compared to the base Cortina 1200’s 15.5cwt/750kg, both remarkably light given their original five seater family car focus.

The Lotus input in these early cars was extensive and expensive leading to a British price of 1100 pounds or about $2700 compared to the $1900 local price of the base Cortina. As a full import, the Australian landed price was estimated to be at least $4000 with the extra duty. For British buyers, it was still a bargain as twin-cam European rivals were at least another 200-300 pounds.

As factory development of the Cortina GT continued in leaps and bounds, hand-fettling by Lotus was reduced enough at the close of 1964 for a price cut back to 990 pounds. By June 1964, the alloy panels had gone, the special Elan gearbox was replaced by the GT item, there was a steel diff housing and Ford’s new two-piece driveshaft absorbed some of the shock which was adding to the diff failures.

During 1964, a Special Equipment version was offered. It also featured the new GT gearbox which made it more tractable on the road. Just 64 examples featured the upgraded engine (105bhp/78kw to 115bhp/86kW) with new camshaft profiles, reworked head with bigger valves and a big bore exhaust system. The stock Lotus blue cam covers were changed to green. The SE also featured Armstrong adjustable rear dampers with different rear coils. The Lotus woodrim steering wheel was leather-covered on later examples and there was a Special Equipment badge at the rear.

This SE upgrade shadowed a similar package for the Elan and defines the most desirable of all early Lotus-Cortinas.

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