Jaguar XK150

Overview

The Jaguar XK150, manufactured by Jaguar from 1957 to 1961, succeeded the XK140. The XK140, introduced in late 1954 as the successor to the XK120, brought with it a series of aesthetic and mechanical enhancements. By 1957, as the XK series was approaching the twilight of its production era, Jaguar unveiled its final variant, the XK150.

Marking the pinnacle of the XK series, the XK150 boasted significant refinements, particularly in its exterior and interior design. A pivotal mechanical upgrade was the introduction of disc brakes, a significant advancement for the model.

Debuting in May 1957, the XK150 was initially available in Fixed Head Coupé (FHC) and Drop Head Coupé (DHC) configurations, with the Open Two Seater (OTS) Roadster variant joining the lineup in March 1958. From October 1959, Jaguar expanded the options with a more powerful 3.8-litre engine, which was available in various tunes alongside the existing 3.4-litre unit.

The Engineering

The XK150 maintained a traditional approach with its separate box-type steel chassis, diverging from the integrated construction seen in the Mk1 and the later E-type. This chassis was a modified, streamlined, and lighter variant of the framework used in the Mark V, echoing the designs of its predecessors, the ‘120’ and ‘140’.

The car featured independent front suspension utilizing wishbones, torsion bars, telescopic dampers, and an anti-roll bar. It retained the Salisbury live rear axle supported by semi-elliptic leaf springs, incorporating telescopic rear shock absorbers, an evolution from the XK140 and a departure from the lever-arm dampers used in the XK120.

Transitioning from the drum brakes of the XK140, the XK150 was equipped with servo-assisted 12-inch Dunlop disc brakes on both front and rear. The vehicle typically featured 16 x 5.5-inch center-lock wire wheels, though there was an option for steel wheels, which could be complemented with spats for the rear wheels.

The XK150 was powered by the same esteemed straight-six engine that was also used in the XK140. This powertrain consisted of a cast-iron block and an aluminum alloy head, equipped with dual overhead camshafts, hemispherical combustion chambers, and inclined valves. It utilized a wet-sump lubrication system, single plug ignition, and a Lucas coil. The engine's displacement stood at 3441cc, achieved with a bore of 83mm and a stroke of 106mm. It was outfitted with two SU H6 sidedraught carburettors, and generally, an 8.0:1 compression ratio was utilized across most markets. In this standard form, the engine delivered a peak power output of 190bhp at 5500rpm and torque of 210lb-ft at 2500rpm.

Top speed of the standard (non-SE) XK150 variants was 124mph and its sprint from 0 - 60 mph took 8.3 seconds, about a tenth quicker than the XK140.

The Story

Initially offered as a Fixed Head Coupé (FHC) and Drop Head Coupé (DHC), the Open Two-Seat Roadster (OTC) version debuted in 1958. The coupés included nominal rear seats.

While bearing resemblance to its predecessors, the XK120 and XK140, the XK150 featured significant updates. A seamless windscreen replaced the split screen, and the contour of the wings was straightened, eliminating the previous drop over the doors. The wider bonnet, which extended down to the wings, and a repositioned bulkhead on the roadster, resulted in a lengthier bonnet. The model was offered in a palette of colors including Red, Pearl Grey, and British Racing Green, among others.

The interior saw the XK140’s walnut dashboard supplanted by leather trim. Early Drop Head Coupés showcased an aluminium center dash panel with an X pattern, reminiscent of the early 3.8 E-type, phased out after June 1958. The redesigned thinner doors enhanced cabin space.

Under the hood, the XK150 initially carried over the XK140's 3.4-litre DOHC Jaguar straight-6, delivering 180 SAE bhp. However, the majority were equipped with the SE engine, boasting larger exhaust valves and 210 SAE bhp. Standard models had twin 1.75-inch SU HD6 carburettors.

Despite initial models being less quick than their predecessors, by spring 1958, the enhanced 3.4-litre "S" engine with three 2-inch SU HD8 carburettors restored performance, offering 250 SAE bhp. In 1960, the engine was enlarged to 3.8 litres, with the standard version producing 220 hp and the "S" version 265 hp. The 3.8-litre 150S models could exceed 135 mph and accelerate from 0-60 mph in approximately 7.0 seconds. Cars ordered to S specification came with all the Special Equipment trim as standard.

The XK150 also introduced four-wheel Dunlop 12-inch disc brakes, a significant upgrade over previous models, though drum brakes were still technically an option. Customers could choose between wire or disc wheels. The suspension and chassis largely mirrored the XK140’s, with rack and pinion steering, and power steering was not available.

By October 1960, production concluded with a total of 2265 Roadsters, 4445 Fixed Head Coupés, and 2672 Drop Head Coupés manufactured.