Featured: Jensen Interceptor Buying Guide

Jensen Interceptor Buying Guide

By Auto Classic
October 24, 2017

When Jensen unveiled the Interceptor at the 1966 Earls Court motor show it was riding on the crest of a wave. A luxurious high-performance car that looked like nothing else. This suave GT was just the thing to capture the mood of the swinging sixties.

Always powered by a V8 and offered with the option of four-wheel drive, the Interceptor came only as a generously proportioned coupé, but later there would be a convertible and for a while there was also a coupé, based on the drophead and built in small numbers (just 46 were made).

Jensen Interceptor inspection checklist

The Jensen Interceptor would go on to notch up nearly 7000 sales in a decade, with further sporadic production once the company stopped trading in 1976. For years the Interceptor was under-valued, but at last these Vignale-designed GTs are starting to command the prices they deserve.

Engine

The Interceptor’s low-tech V8 just keep going with little more than an oil and filter change. Hydraulic tappets mean you don’t even have to keep on top of valve clearances. A huge mileage or poor maintenance will lead to the unit wearing out though, as will lots of short journeys, but rebuilds are surprisingly affordable.

Listen for rumbling as you start the engine and check for an oily film over the V8, along with a smoky exhaust once everything has warmed up. Also check the oil pressure; there should be 25psi showing at idle, and at least 60psi when cruising.

If the exhaust is smoking but none of the other symptoms is evident, it’s more likely that one of the exhaust valves has burned out; fixing this entails a top-end rebuild, usually with a conversion to unleaded petrol.

It’s not unusual for the gasket between the exhaust manifolds and cylinder head to fail. Replacement copper gaskets aren’t expensive but the manifold may need to be skimmed flat as the extreme under-bonnet temperatures can lead to warping.

Interceptor V8s

What kills some Interceptor V8s is overheating; the electric fans can fail to come on while the radiator gets silted up. Get the engine up to temperature and see if the fans cut in; also check for signs of a blown head gasket, although such failures are rare. Thanks to the head and block being made of cast iron, warping of the former isn’t guaranteed, but it is possible.

Many Interceptors have had their original Carter carburettors replaced by Holleys. They’re tricky to keep in tune though, which is why an Edelbrock carb is now the most popular swap. Fuel injection brings a real-world 20mpg tantalisingly close; at the opposite end of the spectrum is the SP (Six Pack), which is thirsty and complex, so it’s tricky to keep in tune.

Gearbox

Simple and strong, the Interceptor’s transmission rarely gives problems. Only the earliest cars came with the option of a manual gearbox and just 24 were built; all others have a Chrysler Torqueflite three-speed auto. Fluid leaks from the Torqueflite can lead to it running dry, so check the level and make sure the fluid hasn’t been in there for decades (you’re looking for pink fluid; if it’s creamy or black, expect trouble). If a complete overhaul is needed it’s unlikely to break the bank.

Suspension and brakes

Until 1969 the Interceptor’s suspension was taken from the Austin Sheerline, so there are kingpins, which wear. Replacements aren’t available so you have to salvage what’s there. Later cars have double-wishbone suspension up front; these feature bushes and washers which wear, leading to vague handling. Fixing everything takes two full days.

The Interceptor’s bulk takes its toll on the springs and dampers, so feel for wallowing in the corners and look for evidence of the car sitting low. You should be able to get two fingers between the top of the tyre. The rear wheelarch when the car is unladen.

Apart from the fitment of anti-lock technology to the FF, the Interceptor’s braking system is conventional, with nothing to worry about. It’s perfectly up to the job too, so upgrades aren’t needed. Everything is available cheaply; the biggest problem is corrosion and seizures through lack of use. The main issue is with the caliper pistons corroding then seizing; each caliper has three pistons.

Bodywork

Rot is an Interceptor weakness and you should assume that any potential buy has at least some of it. Unless the car has been fully rebuilt with a photographic record, the chances are there’s some corrosion somewhere – and fixing it will probably cost plenty.

The entire bottom six inches of an Interceptor is susceptible to rot, which means the sills, floorpans, front and rear valances along with the door bottoms and lower wings. The lower section of the front bulkhead can also dissolve, as can the jacking points, seatbelt mounts and top chassis rails. The stainless steel sill trims can hide some of the rot that is most costly to fix, and with the sills being structural this is one area that shouldn’t be bodged, but often is.

Corrosion is common around the base of the rear screen as well as the hinges for the hatch. Effective repairs are costly as the glass has to be removed, and refitting it accurately can be a nightmare. The front screen is also leak-prone, while the fuel filler flap and bumpers can rot badly.

Use a magnet to check for filler throughout the car; all panels are steel rather than aluminium, but there is plenty of lead loading. These cars were built by hand to a very high standard, so everything should fit superbly.

Interior

Leather trim was standard on all Interceptors, with most cars still featuring the original high-quality hide. Check for split leather and failed stitching, and watch for sagging leather on retrimmed cars. There’s nothing in an Interceptor cabin that will faze a competent trimmer. If everything needs doing because of damp or neglect, expect a big bill.

Later Interceptors came with air-con as standard, while it was optional from the Series II of 1969. There’s a good chance it won’t be working and while the original system can be overhauled you’re usually better off fitting a more efficient modern system – at a price.

History: Jensen Interceptor

  • 1966: The Jensen Interceptor is launched with a manual-gearbox option. The four-wheel drive FF also makes its debut.
  • 1967: Production moves to West Bromwich.
  • 1969: The auto-only Interceptor II gets power steering, optional air-con, a new dash and redesigned seats.
  • 1971: The Interceptor III brings a revised interior and a G-Series engine (lower compression, less power). The SP (Six Pack) replaces the FF. Air-con is standard from August, LHD cars get a 7.2-litre engine from November.
  • 1972: RHD cars get the 7.2-litre engine from May.
  • 1973: The final SP is built and the Interceptor III S4 brings trim changes.
  • 1974: An Interceptor convertible is launched.
  • 1975: The receiver is called in.
  • 1976: Jensen ceases trading.
  • 1983: The Series IV arrives with a 5.9-litre V8; 14 are made up to 1993 when Jensen closes down once more.

PetroFact: Jensen Interceptor

All Interceptors came with a Chrysler-built V8, displacing either 6.3 or 7.2 litres; the Series IV featured a 5.9-litre unit. While the 6.3-litre V8 is the sweeter of the two earlier units, with a more free-revving nature. The 7.2-litre unit is so massively torquey that it ensures effortless accleration and cruising in any conditions.

Claimed by many marque afficionados to offer the build, charisma, performance and luxury of contemporary Aston Martins.  The Jensen Interceptor is far more affordable – and always will be. But at least the Interceptor is starting to be more widely appreciated and values reflect this. As a result a lot of cars that would previously have been broken are now being revived and returned to the road. But there are still a lot of ropey Interceptors out there. Which is why the chances of getting your fingers burned are high.

Buy badly and rising values will help to offset restoration costs. You could still be left massively out of pocket. But buy well and you’ll never look back; driving a properly sorted Interceptor is a joy. The best bit is that you can take the whole family along for the ride.

Prices

  • Project £10,000-30,000  (app. $12,500-$35,000)
  • Good £50,000-90,000 (app. $62,500-$115,000)
  • Concours £85,000-125,000 (app. $100,000-$150,000)

Practicality ★★★★
Running costs ★★
Spares ★★★
DIY Friendly ★★★
Investment ★★★★
Desirability ★★★★

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