Performance road test: a thrusting executive with American V8 power
A couple of months ago we explored the possibilities of installing eight-cylinder Vee engines into various unsuspecting vehicles, including the Europa, Escort, Capri and Cortina. With the exception of the Escort, V8 Fords had been used in the examples we referred to, so it was easy to accept Willment’s offer of an Executive Zodiac equipped with an ordinary American Ford 289 V8 engine rated at 200 b.h.p. for a two-day trial, which included taking performance figures at a Surrey test track.
This Zodiac, which belongs to Peter Mahne who is a director of the aluminium company Hunter Douglas, was built almost exactly along the lines which we were recommending in that article, so it was doubly interesting to be able to explore the practical results of our theories. The pitfalls we mentioned—overheating, strengthening of body, stiffer suspension and better braking—had all been tackled remarkably efficiently, though performance was nothing like one might envisage of a V8 because the whole job had been completed with the accent very much on touring. However, the suspension and braking work allowed this large Gin Palace on Wheels to get across country in Britain at a creditable pace, whilst the driver pondered idly behind the power-assisted steering.
From a standing start the automatic Mustang three-speed transmission was reluctant to accept a loading of more than 2,000 r.p.m. before accelerating away, so the initial take-off was leisurely until 50 m.p.h. or so, when the Executive started strutting along at a great pace towards 90 m.p.h. The standard rear transmission components were retained, including a 3.7-to-1 final drive, and the engine developed maximum power at 4,400 r.p.m so the top speed was limited by valve float at 5,000 r.p.m.! At least that was what the tachometer told us, and in the absence of any further gain in speed we desisted from destroying Mr. Mahne’s engine in the hope of obtaining another 0.5 m.p.h.
Although the Zodiac was immaculate for our test it is no “washed every Sunday, 50 mile per week” machine, having covered a total of 20,000 miles, approximately half that distance being in V8 form. Prior to the insertion of the current power unit, a mildly tuned production 3-litre engine was used in conjunction with the same modified suspension as is fitted at present. Interestingly Willments found that when they lowered the V8 into the space once occupied by a V6, there was no change in ride height, so if there is a difference in weight ‘twixt the two engines, it is a fairly marginal one that did not have to be compensated for in setting the car up for better roadholding.
The 4.7-litre Ford V8 was bought secondhand for its fresh home, but the Mustang transmission was new. This “cooking” V8 was rated at 200 gross b.h.p, developed at 4,400 r.p.m. when new, coupled to a very impressive torque figure of 282 lb. ft. at a leisurely 2,400 revolutions. Bore and stroke dimensions at 4.0 by 2.87 in. sound like those of a high-revving beast, but in the tested form the V8 is right at a low point in its development: the high performance version of the same power unit offered 271 b.h.p. at 6,000 r.p.m. and served as the basis for many a competitive power unit in Mustangs and GT40s.
The new engine slotted into the naked acres of Zodiac engine bay without need to recourse to internal panel work modifications, so far as we could see (Willment’s man confining himself to the titbits printed here and the comment “we spent a lot of time and money developing this car, so I am not about to tell you how we did it!”). The transverse rod across the engine bay is an obvious strengthening measure to provide an extra degree of front end rigidity; a similar idea can be seen on most racing and rally Escorts, while the poor old Anglia seemed to draw its limited handling pretensions mainly from such rods. The production crossmember was suitably braced and V6 engine mountings adapted to a new role in the cause of supporting the V8.
Early tests with the car showed that it had a tendency to overheat and after some thought, and miles, a bigger radiator and separated twin-exhaust systems were installed. Apart from a discreet V8 badge on the boot, these massive mufflers are the only give away to this Q battleship, unless a side view of those 6 in.-wide Minilites is obtained.
The bigger radiator’s temperature is controlled by a pair of thermostatically operated Kenlowe electric fans, their cut-in point being between 70 and 80 degrees C on the Smiths oil temperature gauge fitted into the wooden hole vacated by the water temperature dial normally found on production Zodiacs. This latter modification was the only obvious departure from the standard Executive cockpit, even the automatic transmission “T”-shaped lever and associated slots being just as they left Dagenham, despite operating that imported transmission.
Mike Crabtree, who looks after the Willment performance side at Streatham, was obviously unimpressed by our reporter’s knowledge of the Mk. 4 Zodiac and recommended that we borrowed a late model Executive for comparison. This J.W. agreed to do, but those impressions will have to wait until next month as we could not get a car in time for this month’s press date. However, the points which were not clear to us can quickly be understood by reference to the brochure, disc brakes being standard all round with 9.63 in. front diameter and 10. in. at the back; the Willment version has Ferodo DS11 pads in a successful effort to provide as much “stop” as there is “go”. The Macpherson strut front suspension on the Willment car was substantially uprated by attention to the internal strut valving, but the rear suspension was left untouched, save for a pair of Armstrong Adjustable 22 shockabsorbers, as the coil spring independent system provides just enough room for a heavy load in production form: therefore lowering the ride height would mean the car spending rather too much time on its bump stops, should the car be carrying anything like its full capacity.
Other modifications include moving the spare wheel from its home in between the radiator grille and the engine to the boot, where it rested unsecured at the time of our trial, together with all the tools we were likely to need should something unfortunate happen. Generously proportioned, 185 by 14 in. Goodyear G800 tyres coped nobly with the demands of test track and normal road use.
When the time came to leave the Willment forecourt and face the slightly damp night run down to Sussex, the warnings to take care over handling the car were still very fresh in our ears. In fact, we managed something over 200 miles in the 24-hour loan period and it was only on this first trip that the Zodiac gave us even the slightest heart-quickening moment.
Initially our driver made the mistake of trying to conduct the Willment Executive without the practical, retracting, seat belts in use. A mistake because the plush seats offer little in the way of support, and the power-assisted recirculatory ball steering linked up to the padded 16 1/2 in. wheel needs a fair amount of twirling for any real deviation in course.
The characteristic V8 rumble came through clearly mainly on overrun, though the roar on determined acceleration was still present despite Ford and Willment’s well-sorted efforts on sound deadening. Trickling through London suburbs the car felt rather like a Mercedes 250SE, you even aim it by the bonnet mascot in the same manner. A speedometer which is as near accurate as makes no difference right up to the car’s maximum speed was appreciated as it helped a lot in accurately assessing stopping distances.
Outside town the twin-headlamp system picked up the contours of a long straight B road leading towards Box Hill. From 50 m.p.h. onwards the inertia of the automatic in Drive position was overcome and the palace on wheels burst forward in very impressive manner. In fact the size and floating sensation over the road’s ripples served to make the driver double check the exact width and possible avenues of withdrawal while waiting to overtake. At. 70 m.p.h. it was difficult to hold the car on a stable course, though subsequent familiarisation and a steady throttle opening overcame these problems to a great extent on the return journey.
Having covered 40 miles we set off back to town looking forward to the trip. Our expectations were fully justified for a firm hand on selecting course during the entrance to a long fast bend let the Zodiac power through in a very stable understeering condition without fuss or much body lean. Slower corners were deliberately circumnavigated with respect and at velocity appropriate to an unmodified Mustang running on the same rim widths. A vigorous session at our test track on the following day confirmed that our road impressions had been translated correctly for the car tends to plough straight off course on understeer lock if liberties are taken at low speed. It has far more resistance to roll than the author has observed in standard Zodiacs at lower speeds though, so the conversion has paid off in this respect too, without sacrificing the American style riding characteristics which the 150,000 people who have bought the Mk. 4 Zephyr/Zodiac model apparently prefer.
From personal experience we know that a Zodiac can be made to handle in such a fashion that a four-speed manual, with a standard V6 engine, can be chucked about on opposite lock in the same manner as an Escort! The man who did that conversion was one Barry Lee, who is employed in the family garage called Coventry Hill Service Station at Ilford in Essex. His car was intended for autocross, but the suspension worked equally well on the road, so super sporting executives (and less status-conscious brethren with Mk. 4s) now know where ultimate Zodiac handling can be found. In between the latter standard and production abilities came this Willment version, but they too have the know-how to make alterations according to individual taste.
Reading purely from gross figures (the only one obtainable for the American engine, unfortunately) we found that the V8 engine gives an extra 44 b.h.p. and a boost in torque of 90 lb. ft. Looking through the acceleration figures one finds that the effect has been to make the automatic V8 more than a match for the four-speed manual transmission V6. The top speed is limited by the V8’s ability to rev, so the only answer is a numerically lower rear axle ratio, which isn’t listed in the Ford catalogue.
So far as sustained cruising was concerned the Willment Executive was definitely suitable primarily for Britain’s speed limited roads, continuous speeds of an honest 90 m.p.h. plus being accompanied by temperatures in the order of 90 degrees and 40 lb. oil pressure instead of the usual 50 lb. So good is the sound-proofing and so gallant the engine that one can be flogging it to death without knowing it. No roughness ever betrays the engine’s distress at operating flat out, just the wavering rev-counter needle and other instrument readings, as related.
We found the lack of a throttle kick-down below 60 m.p.h. rather a handicap on roads such as the A24/23, but a modicum of judgement allows the best use to be made of that 50-70 m.p.h. D performance in 6.5 seconds (which compares with that of a TR6 in third gear) and the driver can once again enjoy the luxury of effortless power and ride over any tarmac irregularities, very comfortably enthroned away from the elements, or city traffic. How long one stays ensconced without visiting a petrol station depends, naturally, how twitchy one’s right foot is, but a range of 210 miles to 260 proved within the car’s capabilities; the lower figure including performance testing. Though we were slightly troubled by oil haze from the exhausts after a spell at high speed, there was no detectable difference in the lubricant level recorded by the dipstick after 200 miles: incidentally the sump holds a gallon of Castrol GTX.
By the time that we were heading into our London office and the return of the Zodiac to Streatham, the Zodiac had become a firm friend. The size is sooon acclimatised to and the rumble from that V8 allied to prompt acceleration using the manual holds make the Executive V8 a very agile beast in town, its imposing dimensions and quick take-offs making it a reasonable bet for town use and admirable for luxurious commuting. The brakes were light and superbly graduated, so that lock-up point on the powerfial servo-assistance could be easily judged: all the same it still feels a big car to stop, even compared to a Capri.
We have reported on this modified Zodiac using the standards applied to far more prestigious and expensive machinery, thus a number of criticisms have been voiced. However, the car was a pleasure to drive, made a very welcome change from some of the screaming tin cans and is just the job for those who have graduated the hard way and who want to get their money’s worth from daily motoring with a punch.—J. W.
Willment Zodiac performance figures
0-30 m.p.h… 4.1 sec.
0-60… 10.8 (11.0)*
0-70… 14.5 sec.
Hold 1 .. 58 m.p.h. (25 in Drive).
Hold 2 .. 68 m.p.h. (45 in Drive).
Maximum speed: 98 m.p.h. at 5,000 r.p.m.
Fuel consumption: 14-17 m.p.g. (estimate).
Speedometer error: One m.p.h. fast at 70 m.p.h.
Acceleration in Hold 2: 50-70 m.p.h. .. 6.5 sec.
Converters: John Willment, 189, Streatham High Road, Mitcham.
Car valued at £1,200.