Imp Mk II

September 1965 - October 1968

The number of small design changes became so large that it was decided that the Imp ought to be reintroduced in September 1965.
Mechanically there were major changes, some were new, some had been used over the past few months without making it an issue to the public.

These Mark IIs were fine cars. They were reliable and quiet. But dealers and customers had lost faith.

Changes

• A water pump
• The cylinder head, with larger ports and valves, both inlet and exhaust (no perfomance benefit, compared to a good Mk I, but the casting was easier).
• Inlets were 0.138in larger and exhausts 0.054in bigger in diameter.
• A larger and heavier clutch which lasted longer.
• A modified acceleration pedal for smoother control
• Leathercloth covering of the parcel shelf
• A pair of ashtrays for the rear compartment
• A total of 33lb of underseal and more sound proofing.
• 'Mark II' emblems on the doors
• other changes

Two of the Imp's revolutionary designs kicked the bucket.

• The PTFE Teflon king-pin bushes went quietly.
  If an Imp was left inactive for a while, water would enter the bearings and rust the king-pin, thus destroying the bearings. Also, oil would cause the teflon the swell, and that would make the steering terribly heavy. So traditional bronzes bushes were put in. And from then on the car had four grease nipples for the steering king-pins, and lost its claim of not needing any chassis lubrication at all.
• The automatique choke disappeared (in fact late Mark 1 models already had a hand choke). The choke cable that was installed was lenghty, but it improved durability. The manual choke was not interchangeable with the original for which all spares were available.

The basic saloon was dropped from the range.

In 1967 all cars benefitted from a rearrangement of the front suspension to remove the excessive camber.
The only real changes in the chassis for the whole of the Imp production run came with the Mk 2. Basically the central pivot of the front suspension was lowered to correct the 'toe in' of the front wheels. New (longer) drop brackets and steering rack brackets were used.
There were changes to the spring weights but these were small changes and were standardised to part number 7102489 for the rear and 7102493 for the front from chassis number B.421000101 for a standard, B.4110011227 for a De-luxe, B492004212 for a Sport, B.792001843 for a Chamois Sport and B.301001116 for a Stiletto. I believe these chassis numbers correspond approximately to the introduction of Mk 2.

From an Australian brochure:

New Imp II

1. New smarter styling you can see
   Dual side mouldings with colour flash, chrome wheel trims.
   Wall to wall carpeting.
   Rear armrests and stowage pocket covers.
   Two sunvisors.
   New, smarter design door trims.
   Front and rear bumper over-riders.

2. More comfort and ease of handling you can feel
   Contoured, form-fitting individual front seats.
   New luxury deep foam upholstery.
   Smoother gear changes with bigger clutch (longer clutch life, too).
   Easier breaking - lighter pedal pressure.

3. New quality that makes Imp a lot more carefree
   Bigger capacity, more accessible air-cleaner, new air-intake system and sealed crankcase ventilation for maximum protection against dust.
   New carburettor and choke.
   New throttle control.
   Increased colling efficiency, longer life water-pump.
   Universal joints sealed for longer life.
   Sealed generator bearings.
   Shielded radiator and manifold.
   Heavy duty front shock absorbers -
   all these advancements plus Imp's Coventry Climax designed aluminium rear engine.

New Zinggg

4. Chrysler and Hillman have put new zinggg into light car motoring so you can get more fun out of it. What's behing it all? Well behing you there's a Coventry Climax designed overhead cam aluminium engine - only half the weight of the more conventional engine. So you can get away like a jet, yet can sit on a good cruising speed all day. There's independent suspension all round and even weight distribution to keep Imp II really form on the road, and big brakes that really put a stop to things.

   Add to these an all-synchromesh gearbox and you've got zinggg - a unique advanced type of motoring that only Imp II offers.

More everything

5. More performance due to Imp's many advanced design features.

6. More economy. A real dollar miser, gives 40-45 miles per gallon and only needs servicing every 5000 miles. You'll never get to know your garageman too well.

7. More safety. Imp II really hugs the road. Ample power and big brakes give complete command in any situation.

8. More room. Station wagon roominess with hinged back window and fold-down back seat.

9. More reliability. Outstanding successes in International Rallies, Reliability, Economy and Endurance Trials. The Imp you buy today is proved and perfected. You reap the benefit of experience gained in these rigorous trials.

Holds everything

10. Here's travel comfort for four adults plus luggage. Additional stowage space is available in the front luggage compartment.

11. Imp II has station wagon versatility. Simply fold the rear seat down and you have 16 cubic feet of loadspace. Hinged rear window locks in open position for carrying lengthy articles, surf boards, etc.
    See your Imp dealer now and arrange a demonstration drive. Experience for yourself the new zinggg that Imp II brings to economical high-performance motoring

Mark 3

never badged as such

In October 1968 the Mk II designation was discontinued. The whole range of Imps was revised: all models (except the Stiletto) were given a new interior. They got new seats and upholstery and many variations of external trim. The new facia was full width with a round set of gauges including the speedometer.
This revision is sometimes referred to as the introduction of the Mk 3.

From the 'Mechanical man hour schedule' of November 1968 (MHS 25/6): Service Schedules, p. 38

In the 70s the Triple C magazine had a series by David Vizard: CCC Look-in on the Imp. As a basis, most of their tests were done on a Mk II Imp which had covered some 15,000 miles and was in sound condition.

The first thing that was done, was to measure the engine's flywheel horsepower in an 'as installed' condition, ie. all the ancillary equipment such as dynamo, water pump, etc. fitted, plus the exhaust system with silencer and the engine breathing hot air as it does from under the bonnet.
This resulted in 34 bhp at 4500 rpm.

"It is interesting to note that the factory hp figures under standard conditions quote the standard Mk II Imp engine as 39 bhp at 5000 rpm. Although our test engine may not have been perfect, which may have resulted in some of the discrepancy between our figure and the factory figure, we can see that some of the hp drop must be due to the fact that the engine is breathing hot air, and on a dynomometer test bed, as tested at the factory, it's more than likely breathing air at normal temperature.
"However, the 'as installed' figures are more realistic, because this is actually what you've got to push you along the road."