Today we interrogate Jaguar’s quality claims, explore Browns Lane’s engine policy – and indulge in a spot of counter-factuality.

“Unreliable and unjustifiable, its cars had become a laughing stock, its management a comedy and its accounts a tragedy. Only when it began to take itself very seriously indeed, to cultivate the quality it had previously scorned did things change…” (LJK Setright – Car 1986)

It has been retrospectively stated that the Egan-led quality drive was more illusory than real, which is perhaps a little unfair to the huge effort from all concerned. There was however, in Egan parlance, perhaps a little more sizzle than steak to it. Nevertheless, the reforms had a basis in fact and if the JD Power statistics were any guide, it’s evident that Jaguar made significant strides in this area.

In 1983, BMW’s Eberhard von Kuenheim toured the Browns Lane facility. What he made of it is undocumented, but he must have been, to say the least, given to a measure of incredulity. Nevertheless by then, Jaguar had largely got to grips with building Series III to an acceptable standard. However, that standard remained discernibly lower than that of its Munich rival and at the time, potential suitor.

The XJ bodyshell, while now more accurately put together, remained a patchwork requiring a high degree of hand-finishing, its interior an alluring combination of tastefully matched, finely crafted natural materials and cheap-feeling injection mouldings, while its final assembly remained locked in the past.

A major upswing in durability terms occurred once Jaguar embarked upon a full-time on-site proving regime, building a dedicated base in Phoenix, Arizona. Regular forays to the Nardo test-track in Southern Italy and to the Middle East, Australia and Canada led to significant improvements for the customer.

But what hadn’t changed was the fact that the cars remained sensitive to neglect or careless ownership and were not as robust as they needed to be, especially once they reached their second or third owners. But Series III (and the XJ-S) were late-’60s designs with inbuilt design limitations and there was probably a limit to what could be achieved without significant and highly expensive alterations.

Ironically, the model which formed the bulk of global Series III sales was perhaps the most mechanically fragile. The 4.2 litre version of the long-lived XK in-line six had been something of a botch-job by Jaguar standards. Necessitating an element of jiggery-pokery in order to gain the additional bore widths, the engine became fundamentally compromised from a thermal standpoint.

Reviewing the technicalities of Jaguar’s revived mid-range engine in 1979, Car magazine’s LJK Setright noted the much-needed alterations had resulted in a torque curve of remarkable linearity, with maximum torque being developed at a mere 1500 rpm, which meant the driver never really needed to explore the upper reaches of the rev range, where the 4.2 tended to lose its composure and get decidedly hot under the collar.

Despite its physical size and vast weight, (as heavy as the larger V12), the 4.2 gained a reputation as a fragile engine and was never much regarded within Browns Lane. It’s certainly no accident that the factory never raced it.

Yet it outsold the more complex but superior V12 unit by a huge margin, despite offering broadly similar fuel economy. Yes the twelve cost more – to buy, to service and most likely in depreciation (always a Jaguar bugbear), but it offered something utterly unique – an uncanny smoothness and silence of operation, which as Jim Randle observed to this author, was as close to the characteristics of an electric motor as an internal combustion engine could reasonably be contrived.

But if the V12 cost more, the 4.2 was in turn worth far less. The irony of course being that while the V12 was designed expressly with the US market in mind, it was not sold there (in the XJ saloon at least) from 1983-onwards.

Viewed with hindsight, Jaguar made a fundamental error in prioritising the twelve over a smaller capacity unit. The contemporary thinking was that a V8 could be built on the same architecture, but for a variety of reasons it wasn’t possible (at the time at least) to create a unit which met Jaguar standards of smoothness.

Unfortunately, what doesn’t appear to have been explored was a similarly derived V6 unit. While an experimental 2.7 litre slant six was created off the V12 block, a 60° V6 of broadly similar capacity would have offered a more compact package, the inherent mechanical balance implicit with a 60° inclined angle, and the ability to build it on the same underutilised and expensive transfer line as the twelve.

The primary drawback would of course have been a lack of swept volume, but as an entry level unit, it could have offered many advantages and with the benefit of forced induction, could have given Jaguar the outputs they required. Certainly, a Series III with a lightweight, more fuel efficient (and sweet-running) engine not only seems a highly alluring prospect, but something of a missed opportunity. Furthermore, such a power unit could have proven highly advantageous to BL, being precisely the capacity required for the upper reaches of the Rover SD1 range, for example, rather than the larger than ideal Buick-derived 3.5 litre V8.

By the late ’70s, the necessity for a large-capacity diesel powerplant became apparent within BL. Upon Spen King’s suggestion, a diesel unit based on the block of the existing Rover V8 was developed in conjunction with Perkins. Primarily intended for Land Rover, but also for SD1, there were suggestions at the time that Jaguar could also be a recipient of what became known as the Iceberg programme. However, it fell victim to BL’s cash crisis.

A powertrain project which came a good deal closer to fruition was XJ59 – a Jaguar programme which saw the adoption of a VM Motori turbodiesel which was fitted to a number of SIII development cars around 1981/82. This unit, an in-line six of 3.6 litres, developed 150 bhp at 4200 rpm and 288 lbs ft of torque at 2400 rpm.

Those outputs were broadly similar to the US-spec 4.2 but gave notably better fuel economy. America had briefly embraced diesel following the 1979 oil embargo and Mercedes had introduced diesel versions of both W123 and W126 models, which had proven popular. In 1981, a BL spokesman told Car magazine they planned to introduce it into the US market for the 1983 model year.

However as fuel consumption concerns abated, the diesel XJ, despite having been largely proven was shelved; Jim Randle telling Motor’s Jeremy Sinek in 1983, “should the market require it in future, we could introduce it quite rapidly”. Another missed opportunity perhaps, since such an engine might have opened Jaguar to more of the European market.

Randle expanded a little more on this matter when we spoke in 2016. “We looked at diesel engines in the early ‘80s, using VM. It was built like an Aston Martin engine, where you have a tunnel through the crankcase, and each of the main bearings sits in a circular cup, as it were. It was interesting, turbocharged, but not a performer. It had the potential for finding some extra customers, but in the end, I think, sales and marketing weren’t keen”.

When I put it to him that perhaps a diesel didn’t really fit with Jaguar’s NVH ethos at the time, he replied; “No, it was difficult – mostly airborne [noise] though. We put extra sealing on the bulkheads, and things like that. But no, it didn’t immediately cause you to want to buy one”.

Upon reflection, it does appear that perhaps instead of viewing Browns Lane as a thorny irritant to be subdued, BL might have been better served by having employed Jaguar as the primary power-unit technology-centre for the group. Certainly their V12 engine had the potential to be sliced and diced in a number of ways which could potentially have been highly beneficial to the business as a whole and to Jaguar as a profit centre within the organisation. Another case of the BL charter?

Saving Grace continues here

©Driven to write. All rights reserved.

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