Jaguar XK-120 3.4 Litre
GB
IT'S BEEN SAID SO many times that by now it seems redundant, but no story on the Jaguar XK120 could fail to mention that it was one, of two cars-the other the MG TC-that brought sporting motoring to the U.S. after World War II. The MG was at the low end of our price scale, costing about as much as a Chevrolet, and the Jag was at the Cadillac end. And who could imagine spending $4000 for such a "little" car? Well, a lot of Americans could, and on an international scale the XK120 was a truly remarkable value for its price.
The twin-overhead-camshaft engine of the XK 120 was originally conceived at Jaguar Cars as a sedan engine (for the Mark VII). But the people at Jaguar were so excited about the potential of the engine, once it had reached the prototype stage, that they decided to build a 2-seater for it. The roadster reached the market before the MK VII and it caused a stir in the world of automobiles that hasn't been repeated yet.
Actually there was more than the desire to build a sports car behind the XK120. Apparently Jaguar's testing facilities and staff were severely limited-it was, after all, a period of reconstruction in Coventry and Jaguar was barely established as a car builder before the war. William Lyons, who was and is Mr. Jaguar, reasoned that to put the new engine into a sports car and sell it in small quantities to enthusiastic and, hopefully, knowledgeable drivers ,would be an effective and cheap way of getting hundreds of thousands of test miles and feedback on the rather radical new engine. Thus it was that the XK120 was shown to the world at the 1948 Earls Court Motor Exhibition; the first production models were labelled 1949s. The MK VII sedan appeared a year later as a 1950 model.
The test car, serial no. 671320, is a 1951 model and belongs to Strother MacMinn, an instructor of automotive design at the Art Center School in Los Angeles-the school that trains most of America's car stylists. MacMinn is only the third owner of the car, the first having been photographer Carlyle Blackwell, known to many R&T readers for his racing activities in the early days of SCCA, his concours D Jaguar and, most recently, his kit for the installation of Weber carburetors on Jaguar engines. Blackwell bought the car in August 1951-the early date may explain why it has the old Lucas unsealed headlights. In January 1952 it was sold to a North American Aviation engineer who took it up to about 25,000 miles. MacMinn bought it in 1953, has had it ever since and has kept it in regular if not daily use except for periods when it was undergoing mechanical or body work. It's not a "pure" restored car, but it's close and in good condition throughout. The principal deviation from stock specification is that it now has an XK 140 engine, rated at 190 bhp instead of the XK120's 160. The original engine had been in need of overhaul at 50,000 miles; MacMinn had a chance to get the 140 engine for a good price and after installing it and selling his worn engine had spent far less money than the overhaul would have cost.
MacMinn has had the car repainted a red slightly less "orangey" than the original color and has had the cockpit reupholstered in black leather rather than the original biscuit color. Bodywork is mostly as smooth as it was originally which is to say, not very smooth.
Accurate bodywork or not, the XK120 in its original form has a purity of line and conception that has been approached rarely in any kind of car. It wasn't the product of any modish school of design of the period-though it created one and was devoid of unneccessary or tasteless ornamentation. Its fender skirts, most definitely passe, even seem to look right and later versions such as the XK120 MC with wire wheels and open rear fenders or (worse yet) the XK 140 with chrome strips down the center and a raised body shell, never measured up to the grace and continuity of the original 120's lines even though they were functionally better and perhaps more in line with the current styles. By today's standards it is overly bulky, but it is a classic design in every sense.
Prom the cockpit-and thjs is truly a cockpit, with coaming around the edges and dropped sides where it's so natural to drape your elbow-the view out over the narrow, tapering
hood and the high fenders is even more; the wildly high, 17-in. steering wheel obscures it somewhat for the driver. With the wheel at the forward end of it adjustment range it is still close for today's arms-out tastes, but the short, vertical gearshift lever seems to be in exactly the right place. And there's a proper flyoff handbrake lever just to the right of the gearbox tunnel.
The seats give no lateral support at all; buckets were unheard of in a road car in those days. The seatback is a split bench affair with no rake adjustment. Legroom is limited despite the car length and a driver over 6 ft tall gets no thigh support because his knees are up in the air.
It was standard in English sports cars of the period to have an instrument panel symmetrical with the car center and the 120 is no exception, with a slanted panel protruding from the main dash. Speedometer and tachometer are large, white-on-black dials with the tach near the driver and the speedo better read by the passenger; the tach needle climbs counterclockwise and is in symmetry with the speedo needle's clockwise motion once the car is in 4th gear. Instrumentation is what we call "complete" nowadays, with the important plus (especially considering the XK's oil consumption) of a pushbutton that transforms the fuel gauge into an oil level gauge. The infamous Smiths instrument combined oil pressure and water temperature in dead center and as the temperature half is dead-which was normal-;-on the test car an extra temperature gauge haS' been installed over to the left of the steering column.
The windshield is a split, flat-pane affair and atop the cowl (scuttle) is a convex mirror for a miniaturized rear view. There is no outside mirror on the test car, and while we were out motoring the owner was ticketed for not having one. He'd driven the car 16 years without an accident, yes . . . but the law is the law; isn't it? And while we're on the subject of vision out of the car, one comment describes the situation with the top and side curtains up: there isn't any.
But the only way to drive this car is with the top down, and that's just what MacMinn does-even on long trips. The wind pattern isn't bad; there are no terrible drafts around the back of your head. And as with any roadster the extraneous
noises-like gearbox whine, valve clatter, rattIes an~ sque~ks -get lost in the smooth rush of wind over the shell, the most noticeable noise being the lovely purr of the exhaust pipe. Top and side curtains are purely makeshift; in 1951 an open roadster was an open roadster and one used these things only as a last resort. With them in place the passengers are shielded from the worst of the elements, and there's a certain coziness about driving with them up; like being in a house that creaks, groans and leaks a bit when there's a storm you feel more sheltered than if you couldn't tell there was a storm. By the way, the test car had no heater, but considerable engine heat found its way into the cockpit.
In these days 160 bhp, or even the 190 of the test car, doesn't seem much in a 3000-lb car. But remember, when the XK 120 appeared the only other 160-bhp car familiar to Americans was the 2-ton Cadillac. The engine in MacMinn's car is still fairly smooth mechanically and it idles nicely at 800 rpm. To preserve the machinery we used a 4500-rpm rev limit and got off the line with only a mild chirp of the tires, winding up with performance figures that resembled the Autocar road test of 1950 more than our own test of 1951. Because the figures we got are definitely in the range of 120 performance reported when it was new (our own test produced faster times) we've used them for the data panel; the low rev limit used cancels the 140 engine's higher power rating.
MacMinn has solved some of the 120's engine problems. An electric fan from an E-type, controlled by a toggle switch under the dash and mounted on a sturdy pedestal in front of the radiator, plus a 7-psi radiator cap to raise the boiling point by 20oP, cure its legendary cooling deficiencies nicely. And he has hooked the once-automatic electric choke to what used to be the instrument light switch; it is common among Jaguar owners to go to manual operation of this choke.
The venerable Moss gearbox that Jaguar used for so many years is still with us in Morgans, and when we tested the new Morgan Plus 8 we complained not only of its marginal synchromesh but of its stiff action. We also noted that the stiffness wears. off with age, and MacMinn's 120 bears this out. But it takes a deft hand to shift without graunching.
The 120's boulevard ride is still good by modern sports car standards; it must have been sensational for its day. We seem to recall that Tom McCahill said that it rode like a Cadillac and if that's an overstatement at least we might say that in. the XK 120 was the germination of the whole idea of GT: speed and handling-with comfort. On less-than-smooth roads the harshness is nothing to complain about and the 120 has a freedom from pitch that some present sedans of comparable weight don't have. The body does creak and rattle, but not horrendously.
Steering effort is high-we've become spoiled by light cars and power steering-but it's not a Herculean task for a man to park the car, and it feels precise enough. Por handling on smooth roads (we didn't subject the car to the usual bump-and-grind routine) the 120 clings surprisingly well on its 6.00-16 Michelins, getting through a familiar corner at a speed that would be respectable for, say, a modern medium-price roadster and going into a final oversteer attitude early after its initial understeer. This characteristic is common in vintage sports cars; we must have been much more attuned to "reverse lock" in cornering than we are now.
XK 120s weren't known for braking prowess in their original form, and in our present-day tests tney barely survived one "panic stop" from 80 mph. In this test they came on timidly, worked up to a deceleration rate of 0.65g, never hinted at locking the wheels and began to fade before the car was halted. MacMinn declined to let us run the fade test (six stops from 60 mph at 0.5g), but we think they would have required at least a doubling of pedal effort by the sixth stop. The Girling drums are of large diameter, 12 in., but aren't very wide so that the swept area is meager. We must
say that the brakes worked well in mild driving, pulling straight and requiring only moderately heavy pedal effort.
That's the Jaguar XK120 from the 1970 viewpoint. It looks great and performs well. What's really neat about it is that it is still a distinct pleasure to drive, at least in open form on a beautiful day, exhibiting a minimum of "old crock" characteristics. Even if the earliest models of it amounted to factory test cars, it opened up a market that not even Jaguar suspected, and Jaguar followed through by producing an astounding car in the quantities required at a reasonable price. Later, after the XK140 and XK150 (which were really updated 120s), the company again set sports car design ahead by years with the E-type. Will they ever do it again? We wonder. These days startling new cars are few and far between. Perhaps progress in the design of conventional cars-that is, cars with internal-combustion engines, four wheels and manual guidance-has peaked out and we'll have to content ourselves with niggling refinements until something really new happens. But the XK120 gave us something to remember, something that makes us say, "Boy, back in the early 1950s . . ."
back to road test index
other fifties road tests:
other sixties road tests:
other seventies road tests:
other eighties road tests:
Author: ArchitectPage
PRICE
List price, west coast (1951). $3945 Price as tested. . . . . . . . . . . . . $3945
ENGINE
Type.... . . . . . . . .. . inline 6, dohc
Bore x stroke, mm. . . .83.0 x 106.0
Equivalent in...... .. .3.27 x 4.17
Displacement, cc/cu in.. .3442/210
Compression ratio.. . . . . . . . . .8.0:1
Bhp @ rpm. . . . . . . . . .160 @ 5400
Equivalent mph. . . . . . . . . . . .120
Torque @ rpm......... .195 @ 2500
Equivalent mph. . . . . . . . . . . . .55
Carburetion... .two 1j4-in. SU H6
Type fuel required.. . . . premium
DRIVE TRAIN
Transmission. . . . . A-speed manual Gear ratios: 4th (1.00). . . . . .3.64: 1
3rd (1.37).. . ... . . . . . . .. .4.98:1
2nd (1.98). . . . . . . . . . . . . .7.22:1
1st (3.38)....................... .12.29:1
Final drive ratio. . . . . . . . . . .3.64:1
CHASSIS & BODY Body/frame: steel "X" frame with separate steel-aluminum body
Brake type: 12.0 x 2.25-in. drum
front & rear
Swept area, sq in. . ......... .. .339
Wheels... . . . . .. . steel disc, 16 x 5
Tires. . . . . . . .. . Michelin X 6.00-16
Steering type. . . . recirculating ball
Turns, lock-to-Iock............... .3.25
Turning circle, ft.................. .31.0
Front suspension: unequal-length A-arms, torsion bars, tube shocks, anti-roll bar
Rear suspension: live axle on leaf springs, piston shocks
ACCOMMODATION
Seating capacity, persons........................................ 2
Seat width.. . .. .. .. .. .. . .2 x 18.0
Head room... . . . .. . . . . . . . .. .36.0
Seat back adjustment, degrees...O
Driver comfort rating (scale of 100):
Driver 69 in. tall. . . .. .. .. .. .70
Driver 72 in. tall. . . .. . .. .. . .45
Driver 75 in. tall. . . .. .. .. .. .40
INSTRUMENTATION
Instruments: 140-mph speedo, 6000-rpm tach, 99,999 odo, 999.9 trip odo, oil press, water temp, ammeter, fuel & oil level, clockWarning lights: generator, high beam
GENERAL
Curb weight, lb. . . . . . . . . . . . .3015
Test weight.. .. . . . . . . . . . . . . .3280
Weight distribution (with
driver), front/rear, %. . . .47/53
Wheelbase, in. . . . . . . . . . . . . .102.0
Track, front/rear......... . . .51.0/50.0
Overall length....................... .173.0
Width. . . . . . . . . . . . . . . . . . . .61.5
Height. . . . . . . . . . . . . . . . . . . .52.5
Ground clearance..................... 7.1
Overhang, front/rear... .24.0/47.0
Usable trunk space, cu ft. . . . . .6.5
Fuel tank capacity, U.S. gal.. .18.0
CALCULATED DATA
Lb/bhp (test weight). . . . . . . . .20.4 Mph/1000 rpm (4th gear). . . . .22.1 Engine revs/mi (60 mph)... . .2715 Engine speed @ 70 mph. . . . .3170 Piston travel, ft/mi.. . . . . . . . .1885 Cu ft/ton mi.. .. .. . .. .. .. .. .. 10 1
R&T wear index.................... .51.2
R&T steering index................ .1.01
Brake swept area sq in/ton. . . .128ROAD TEST RESULTS
ACCELERATION
Time to distance, see: .
0-100 ft. . . . . . . .. .3.3
0-250 ft. . . . . . . . . .6.2
0-500 ft. . . . . . . . . . . . . . . . . . .9.8
0-750 ft. . . . . . . . . . . . . . . . . .12.8
0-1000 ft. . . . . . . . . . . . . . . . .15.3
0-1320 ft (1/4 mi). . . . . . . . . .18.3
Speed at end of 1/4 mi, mph................
Time to speed, see: 0-30 mph. . . . . . . . . . . . . . . . . .4.2
0-40 mph. . . . . . . . . . . . . . . . . .6.1
0-50 mph. . . . . . . . . . . . . . . . . .8.3
0-60 mph... . . . . . . . . . . . . . .11.7
0-70 mph. . . . . . . . . . . . . . . . .15.9
0-80 mph. . . . . . . . . . . . . . . . .21.7
0-100 mph.. . . . . . . . . .35.9
Passing exposure time, see:
To pass car going 50 mph. . . .7.0
FUEL CONSUMPTION Normal driving, mpg. . .. .19.0
Cruising range, mi................................... . . . . . . . .340
