The Jensen Interceptor was an icon of English opulence, a giant by 1970’s standards, with power that few cars matched; a sumptuous grand tourer with endless torque and stunning beauty.
Sadly these exquisite monuments were built in the 70s, with all that entails and the 50 years since have not been kind to most them; rust is the common curse of the Jensen, leaking seals often cause the interiors to rot and the engines, whilst sturdy, without good maintenance suffer.
With less than 4500 made, these cars were rare to start with and that number has rapidly declined with barely 300 left on the UK roads (308 registered and 169 SORN Q.4 2019), making these one of the more sought after and cherished marques.
This example seemed to have missed the memo on how it should be holding up, when it rolled into our workshop we were stunned at the condition of the chassis, let alone the bodywork; while it needed paint and was leaking from everywhere, structurally it was incredibly sound and the interior needed little more than a thorough clean and some minor repairs.
This diamond escaped the 70s relatively unscathed and we have lifted it up to the levels deserving of a true piece of automotive history.
The chassis was stripped, cleaned and inspected, needing only 2 small sections to be attended to, an incredible achievement for any car of the 70's let alone a Jensen. There were signs of other repairs having been performed previously, although they were limited work, but they had been carried out well and didn’t need to be revisited.
The most recent owner had all of the suspension replaced, with the springs, shocks and all bushes in incredible condition; they were all removed, to allow the metalwork to be inspected and cleaned, but once done, the major elements were put back and they simply did not need to be replaced.
A fresh coat of underseal was applied to maintain the excellent condition and the build moved onto the mechanical side to the underbelly.
The differential, axle and propshaft were removed, with leaks from every angle, the final drive needed to be stripped and inspected at the very least and upon doing so, thankfully, the main gears were in remarkable condition and so the bearings were replaced, along with the seals, the unit was rebuilt and all new gaskets and fresh oil completed the service.
The gearbox was a similar sight, but all of the leaking oil was coming from the rear seal, not the front or the pan. When the oil was dropped out, it was still a very good colour and the filter looked to have been recently replaced, indicating, at the very least, the last owner did more than simply change the engine oil when servicing it.
Sadly the gearbox, especially when automatic, is all too often neglected, when in reality they need little maintenance and will often outlast the engine and often the car.
Despite the indication of good maintenance, the unit was thoroughly inspected, although the happy outcome was a very healthy box, which only needed a clean up, service, seals and new oil to return the unit to production.
Barely running enough to limp it into the workshop and leaking from just about everywhere, the engine was in need of rescue.
Testing showed a fairly even compression across 7 of the cylinders, however cylinder 8 was running with half the pressure of the others, meaning a full rebuild was required.
When it was stripped piston 8 was found to have a snapped pressure ring, which explained the low reading, but in general the interior wasn’t too bad, with fairly clean oil and water channels, a good sign that reasonable care had been taken over the years.
The cylinders were re-honed, with new pistons and rings fitted, the crank was checked for roundness and polished and the bottom end was rebuilt with high quality bearings and new bolts.
The heads once cleaned up were sadly found to be destined for the scrap heap as both had serious cracks leading into the head from their respective valve seats. We did attempt to weld the cracks, which worked and they passed numerous pressure tests, however, we had no way of telling how deep the cracks went and thus no way of guaranteeing they wouldn't reassert themselves after a few heat cycles. As such, we decided to fit new Edelbrock high-flow heads, which look incredible and will improve the breathing of the engine.
With the new heads on, the powder coated bracketry and new ancillaries were bolted on and the engine was dressed, ready to be refitted.
The 440ci Chrysler engine that nestles in the front of the Jensen typically had issues keeping itself cool; this was emphasised with the Six-Pack (SP) variant, which would regularly overheat, especially when maintenance was lax.
While the engine for our Jensen had been rebuilt and thus its coolant channels are crystal clear, the original system simply wouldn't have been sufficient to ensure an even temperature, so we added our standard intelligent cooling package to make sure.
A larger radiator was fitted, which allows for greater coolant flow and thus exposure to the cooling fins, taking more heat out of the fluid. This was coupled with an electric water pump, replacing the standard unit, electric fans and an intelligent controller, completed with waterless coolant.
Mechanical pumps have the main issue that they only run at engine speed, meaning that when the car is stationary, or slow moving, the pump is turning at engine tick-over, when the coolant may be rising in temperature and in need of more rapid cycling. The electric pump enables flow to be as fast or as slow as needed.
Likewise the electric fans can be run whenever is required at whatever speed is deemed appropriate, which is often much faster than a mechnical fan at idle, when the car isn't moving.
Controlling these elements is an intelligent module that reads engine temperature and runs the fans and pump as much as is needed to maintain a constant temperature.
This controller has the added advantage of being able to slow the use of the pump when the engine is cold, allowing a quicker warm-up and reducing emissions and fuel usage. Equally, when the engine has been stopped and the engine bay temperature rises (the bay acts like an oven, when the engine stops, the latent heat is no longer being removed and the insulation of the bay causes the temperature to rise for a time before it dissipates), the pump and fans can be run for as long as is needed to reduce the temperature. This greatly improves the longevity of the engine.
Waterless coolant is used in all of our builds. Containing no water it prevents oxidisation and thus no rust forms in the channels. Additionally, it has a higher boiling point, meaning that even in hot weather, with the engine under load, there is no risk of gas being released from the coolant and creating hot-spots.
The other main advantage of these fluids is that they gain and release heat more quickly than standard coolants and thus draw the heat from the engine more efficiently and release it via the radiator in the same manner.
All in all, this combination of elements tames the heat of this incredible engine and makes for a more reliable, more enjoyable car.
The original 4 barrel carburettor that adorned the 7.2L heart of the Jensen was an effective unit, it worked reasonably well, but often went out of tune and suffered the same shortfalls that all carbs did, that of limited tuning, hot and cold start problems and performance.
Fuel injection is an incredible update to this power unit, it provides a smooth drive, more akin to a modern engine, it eliminates the hot and cold start problems and allows for granular tuning across the entire rev-range, ensuring the best performance at any speed, in any gear, with any throttle position.
However, replacing the carburettor with an injection unit changes the landscape of the engine, it alters how it looks and removes that originality. As such, we have employed a sympathetic system, which uses a carburettor chassis as a throttle body, incorporating twin downdraft injectors. This unit provides the benefits of fuel injection, with the aesthetics of the original engine.
A learning ECU was installed in the passenger footwell, which, combined with a high-pressure pump, temperature, throttle position, O2 and air flow sensors, read the engine conditions and tune the flow of fuel accordingly.
The result is tantamount to a transformation, providing a smoother running, cleaner revving engine that produces more power and will always start.
While the body was in excellent physical condition with almost no rust, the paintwork was sadly not so lucky.
The previous respray wasn't done to a very high standard, runs were visible in numerous places, orange peel could be seen, waves in the paint and a poor standard of finish in general. This would have been grounds for a respray anyway as only the best paintwork is allowed to leave our workshop, however the body was replete with scratches, cracks in the paint and a few minor dents.
As such, the body was stripped and the panels were taken down to the metal to ensure the best base for what can only be described as a sumptuous coating of paint.
Once flat and finished, a black primer was applied, which is the best base coat for the beautiful blue that this car wears. It enhances the top colour and gives a depth to it that a lighter primer cannot do.
Once the top coats were laid, it was covered in multiple layers of lacquer to add to that depth, completing a truly opulent finish of this magnificent car.
Amongst the other surprises in this cars condition was the brightwork. Almost all of the chrome on the car was in excellent condition, with the bumpers and trim pieces needing nothing more than a clean and polish. Only a couple of items such as the inner and outer door hands needed to be re-chromed. When put back on the car, these pieces accentuated the paint, enhancing it's draw.
The interior was by far the most impressive element of this car in terms of its condition. It appears to be the original leather, with no cracks, tears, rips or damage whatsoever, with the exception of some colour wear on the driver’s seat and rear of the headlining. A truly impressive condition for a Jensen interior.
The previous owner clearly took great care of the leather, feeding it regularly and keeping it in beautiful condition.
With the small repairs made, the only other elements that required attention were a few replaced switches that had lost their decals, the air vents a few gauge surrounds and we finished the look off with a lovely Mota-Lita steering wheel, which simply finishes off the sumptious look.
Copyright © 2021 Hawk Classics - All Rights Reserved.