Ford Escort Mark 1 RS Twin Cam and RS 1600

Production	1968 to 1974
Assembly	Halewood & Boreham England UK
Body style	2-door saloon
Engine	1,558 cc Lotus Twin Cam 1600 BDA
Wheelbase	94.5 in (2,400 mm)
Length	159.25 in (4,045 mm)
Width	61.8 in (1,570 mm)
Height	58.5 in (1,486 mm)

The Ford Escort mk1 RS Twin Cam and RS1600 was a sports car built by Ford for race and road use in the late 1960s to the mid 1970s.

History

The model was initially a higher performance version for rallies and racing built for Group 2 international rallying, produced as the Escort Twin Cam in the regular assembly line in Halewood and completed in a remote corner of the plant. Around 1,100 vehicles were planned to be built there. However, when management realized that for every '49 body a standard Escort and a half was out of stock, production at Halewood was terminated. Further copies were made at Ford Motorsport in Boreham. The RS Twin Cam was built from 1968 to 1971.

The Escort was originally designed without considering the demands of motorsport. However, Ford Motorsport organized an early example and fit-tested the mechanics of the Lotus Cortina over a weekend. The Escort had conventional rear-wheel drive and a four-speed manual gearbox The front axle of this competition car was easy to assemble, as was the rear axle with only minimal modifications. However, the Lotus engine fitted because of its expansive cylinder head with cast-on intake ducts and the voluminous carburettor and air filter system only fitted under the bonnet Its Lotus-made eight-valve twin camshaft head fitted to the 1.5 L non-crossflow block, which had a bigger bore than usual to give a capacity of 1,558 cc and an around 110 hp, when the front end of the engine was shifted a few centimetres to the left (in the direction of travel). So, the engine didn't sit neatly straight in the engine compartment, but was slightly twisted to the left. The battery had to be moved to the trunk to make room for the exhaust. The Escort was also the first small Ford to use rack-and-pinion steering. In order to accommodate the significantly larger transmission of the Cortina, the bulkhead and transmission tunnel were modified accordingly with just use of a two-kilo hammer. Some of the optional accessories exhaust competition manifolds; light-alloy wheels, 6" wide rims; limited slip final drive; heavy-duty front
suspension; adjustable rear telescopic dampers; competition brakes; close ratio 3-speed mechanical gearbox (1st 2.296, 2nd 1.697, 3rd 1.280),and 4.700 5.100 5.500 axle ratios. 

Body changes were limited to slightly wider rear fenders to cover the wide rear axle, flared front wheel arches, reinforcement plates on the strut mounts and the modified transmission tunnel for the Cortina 2000E gearbox. Such bodies ran in production as "Type 49" and had chassis numbers that began with "49”. With wider 5.5j 13" steel deep dish wheels similar to the lotus Cortina these later became vented on the Rs 1600 and only a small round badge at the rear and badges on the wings the look was still very similar to the normal mk1 escort. More designs came on the later AVO RS range of cars. The car could reach 115mph.

PERFORMANCE: Ford Escort RS Twin Cam

• engine capacity 95.07 cu in, 1,558 cu cm
• fuel consumption 23.6 m/imp gal, 19.6 m/US gal
• max speed 115 mph, 185 km/h
• max power (SAE): 115 hp at 6,000 rpm
• max torque (SAE): 106 1b ft, 14.6 kg m at 4,500 rpm
• max engine rpm: 6,600
• specific power: 73.8 hp/l
• power-weight ratio: 15 lb/hp, 6.8 kg/hp
• acceleration: standing 1/4 mile 17.2 sec, 0—50 mph (0—80 km/h) 7.2 sec
• max speeds: 39.5 mph, 63.6 km/h in 1st gear; 58 mph, 93.4 km/h
• in 2nd gear; 84 mph, 135.2 km/h in 3rd gear; 115 mph, 185 km/h in 4th gear

Production of the Twin Cam, was phased out as the RS1600 was to be developed around just over 800 of the planned 1000 being built. 

The Lotus engine gradually proved to be no longer powerful enough and also not particularly reliable in sports use, as well as being complex and expensive to maintain. That's why Cosworth became tasked with designing a new four-valve cylinder head for the existing block. The resulting BDA engine replaced the Lotus four-cylinder in the otherwise unchanged vehicle, which was then marketed as the Escort RS 1600. The RS1600 used a Kent engine block with a 16-valve Cosworth cylinder head.

RS1600 were built at the AVO Plant Ford's (Advanced Vehicle Operations facility at the Aveley in South Essex UK. These models featured more strengthened bodyshells with more options.

The BDA engine was also installed askew in the engine compartment, although this was no longer necessary because of its considerably slimmer dimensions. Taking advantage of all production and repair tolerances, the BDA had 1601 cm³ and was therefore allowed to be enlarged to a displacement of up to two litres in sport. A few hundred examples of the RS1600 were built in Boreham. With the existing cast iron block, however, no more than 1835 cm³ could be realized. The external tuner Without Ford's knowledge, Brian Hart had designed an aluminium engine block on his own that could replace the gray cast iron block and offered the possibility of realizing a displacement of two litres.

The sports specimens had a displacement of two litres and rear axles with four trailing arms (the top two pointing backwards), a Panhard rod and coil springs. With such vehicles, The Ford works team was practically unbeatable in the late 1960s and early 1970s, the Ford team with drivers such as Roger Clark, Timo Mäkinen and Hannu Mikkola was able to achieve numerous successes in rallying.

Ford made all the works team's developments generally available through its well-developed RS dealer network, especially in Great Britain, as soon as they proved to be useful and stable. In this way, each team, assuming the appropriate financial strength, could prepare vehicles to factory standards. As a result, Ford was often defeated by private teams in competitions, but this was not a bad thing for marketing reasons. This made Escort RS very popular competition vehicles in Great Britain. There was the phrase that every weekend somewhere in the UK there is some event that is won with an escort.

Ford Escort RS1600