The Ian Walker Cortina GT

Tuning, that near-magical word so loosely used nowadays to describe all manner of operations varying from port-polishing to suspension-stiffening, was once the preserve of an exclusive band of men who relied more on their instinct than on electronic machines to extract from motor cars that extra edge of performance which was not there when they left the production lines. Nowadays, the situation is somewhat different and prospering tuning shops are to be found tucked away in countless motor establishments from the most bizarre, neon-lit show-piece to the tool-strewn, back street garage.

Despite the increase in both supply of and demand for performance tuning, the work is mainly carried out on behalf of the racing fraternity. Rallying, although catered for by many more commercial organisations than a year ago, remains a sport for which car preparation is looked upon as largely the preserve of the participants themselves. The reasons are several, but not the least of them is the fad that the choice of specialist equipment to be fitted to a rally car depends a great deal on personal preference and the number of available combinations are far too numerous to have modified cars on display in showrooms.

One of the tuning concerns which has become geared to rally preparation is the Ian Walker establishment at Finchley. Perhaps better known for its work in connection with racing, this stable offers a rally version of the Ford Cortina GT, but, with an obvious eye on the individual tastes of its customers, makes no definite pronouncement of its specification. The Walker Cortina GT is, rather, a flexible combination of a number of optional qualities, which is the reason why no single demonstration car exists as such. A Walker-tuned Cortina GT was entered. by the firm in the 1965 R.A.C. International Rally and it is this car, suitably restored after its pounding, which is the subject of this report.

The engine, which has already propelled the car over nearly 6,000 miles, is fitted with a cylinder head of the firm’s own design, skimmed and polished, and giving a compression ratio of 10.5 to 1. Larger valves are not fitted, but the inlet tracts are opened out. The camshaft, too, is to Walker’s own specification and each tappet has a clearance of 15 thou. The entire engine has been stripped and balanced, the crankshaft modified, Lotus-Cortina connecting rods fitted and Vandervell racing big-end and main bearing shells. The flywheel has been double-dowelled and a high pressure relief valve fitted to the high delivery oil pump. A special felt element is used in the oil filter. New plugs and points; and an electronic check, complete the treatment. The Weber carburetter remains unchanged.

During the test we found that the conversion slightly detracted from the low-down performance, a trait emphasised perhaps by the gear ratios which had been chosen for this car, but this was offset by the spirited urgency which it possessed whenever engine speed approached 4,000 r.p.m. Suspension stiffening and underbody protection are as vital to successful rallying as increasing the power output of the engine, and these facets of tuning have not been overlooked. At the front, uprated struts are fitted, together with lowered coil springs, an export-type cross-member and a sturdy anti-roll bar. The rear springs have been lowered by means of blocks, giving the car 2 in. less ground clearance, and the Adjustaride shock-absorbers have been considerable uprated. A substantial sump shield is also available, but this had been removed from the car before the test. Competition brake pads and linings and a servo unit are also fitted. Wheels are 4 1/2J fitted with 1.65 x 13 Pirelli Cinturatos. The laminated screen is wiped by Trico Speedblades.

The gearing most favoured by those who rally Cortina GT’s is that provided by a standard box fitted with an uprated second gear. This can be supplied, but the test car was fitted with the close-ratio box which is standard equipment on the Lotus Elan (ratios: 1st 2.510, 2nd 1.636, 3rd 1.230) and mates normally with a 3.9 rear axle. The rear axle ratio on the test car was 4.4. although 4.1 and 3.7 are available. The resultant uprating of bottom gear rendered driving in London more demanding a task than desirable and led us to the belief that this particular combination of car and gearbox would, in the hands of the uninitiated, lead to premature clutch wear. It is not a shopping car by any means. Another result of the choice of gearbox was an inability to make a really smart getaway, although once the clutch was fully engaged, comparatively high engine r.p.m. being used in the process, acceleration was smooth and progressive. This also affected its times on standing start tests, the figure for 0-30 m.p.h. actually being 0.1 sec, higher than that for a production model. Times from rest to higher speeds were, however, considerably improved although a gear change which became necessary in the last twenty yards or so of the standing 1/4-mile may well have affected that figure. For rallying, in which frequent stops are often necessary, we would certainly opt for the standard box with uprated 2nd gear.

A very attractive and extremely comfortable Avanti leather-covered steering wheel was fitted, having a diameter of 13 in. This combined well with the luxurious and body-gripping Pullman seat to produce a relaxed driving position with the gear lever nicely to hand. Some difficulty was at first experienced in selecting 1st gear and 2nd, but this was caused by the lever entering the neck of the reverse position even though it was not lifted. This could prove to be embarrassing in the heat of a special stage, but was quite manageable under normal driving conditions as soon as the cause was realised. It was disappointing to find that the Britax safety belts were pillar mounted. Low mountings are safer and, above all, far more comfortable to the wearer.

Lights; more than anything else perhaps; are items of which rallyists have varied opinions and Walker has no set positions for either the ancillary lamps themselves or for the switches which control them. A favourite position for switches on the Cortina is on the front-facing surface of the inter-seat cubbyhole, and rubber plugs gave the game away that this is where they had been mounted on the test car during the R.A.C. Rally. There were no extra lights, but a variety of lamps, both iodine quartz and conventional, are available, together with an easily accessible fuse box, heavy-duty battery, 28-amp regulator and a heavy-duty generator. The headlights of the test car had been replaced by Cibie 22 conventional units which produced a dip beam possessed of such a sharp cut-off that it was possible to fully illuminate the rear of a car in front with no stray light whatsoever entering its rear window. These units are characterised by concave lenses.

Among the other items which it is possible to have fitted to a Walker-tuned Cortina GT are oil coolers, long-range fuel tanks with shielding, fuel line and hydraulic line protecting pipes, lamp mounting frames, a variety of navigational instruments and such oddments as bonnet-retaining straps and T-junctions for speedometer drives. Needless to say, there can he no quoted price, for the cost of modification varies between £47 and £125.

Even in standard form, the Ford Cortina GT is a desirable motor car and a week spent with the Walker variety was indeed a pleasant one. The modified suspension and wide wheels produced a ride which did not appear to be any harder for its firm predictability. On smooth roads, cornering at speed was a joy. Breakaway, when it came, was completely anticipated and the application of opposite lock through the small-diameter steering wheel was quick and effective. We could not take the car in its unshielded state into the rough, but a rapid journey over a meandering gravel track—a private one, I hasten to add—proved that it was quite at home coping with unsealed surfaces.

Peak performance came at 6,000 r.p.m. (80 b.h.p. at the rear wheels) after which there was a rapid fall off in power, although 7,000 r.p.m. was possible in top. It was necessary, in order to avoid undue clutch-slipping, to use at least 4,000 r.p.m. when starting from rest, even at town traffic lights, but this, as has already been explained, would be entirely obviated by the use of alternative gear ratios. In just over 400 miles of pottering in London, airing it on the A20 and making fast laps of a private test circuit, the car returned a fuel (the best) consumption figure of 23 m.p.g. The throttle stop had been adjusted to a fast idling speed to prevent fluffing at tick-over. A quart of oil was added in this distance.

Despite the unsuitable overall transmission ratios, this version of the Walker GT produced a pleasant week’s motoring; one during which it became patently obvious why the Cortina has become so widely used by Britain’s rallyists as a base for at extremely competitive motor car.—G.P.