Automotive

I was doing a little research today in my "library", perusing the back pages of Classic & Sports Car magazines, when I came across an advert from a company (Clocks4Classics) whose product could repair the tachometer on my Lotus, which hasn't worked since we put in electronic ignition. I had to know more, so I went to the website and learned that they can fix vintage automotive clocks AND tachometers!

Gosh, does anyone have an old car with a clock or tach that doesn't work? Raise your hand.

Here's the explanation for the clock:

How THE SMITHS CLOCK MOVEMENT  Works

The Smiths Pin Clock is a fascinating combination of mechanical and electrical techniques. The clock is based around a traditional clockwork mechanism with a rotating balance wheel and hairspring. The balance wheel rotates backwards and forwards at a fixed rate of five times per second and it is this motion which is used to regulate the timekeeping of the clock.

In order to maintain the oscillation of the balance wheel, the clock has to be provided with energy to overcome the losses in the mechanism.  In a traditional clockwork mechanism this energy is provided by a mainspring wound by a key, but in this case the energy is provided electrically.  A small solenoid coil consisting of thousands of turns of fine wire is mounted close to the balance wheel.  Two shaped metal `pole pieces’ pass through the center of the coil and are positioned so that their ends are very close to the edge of the balance wheel. When the solenoid coil is energized by an electric current a magnetic field is created and this provides a `kick’ which maintains the oscillation of the balance wheel.  For the clock to operate correctly the electric current to the solenoid coil has to switched on for a very brief period at exactly the right point in the movement of the balance wheel. This is achieved by using a tiny set of electrical contacts which brush against a small pin projecting from the underside of the balance wheel – hence the name `Pin Clock’.

NOTE: this is very similar in theory to early electronic watch movements, like this one in a Seiko pocket watch.

What Goes Wrong?
A quick calculation shows that the electrical contacts operate over 3 million times a week – or 157 million times a year! Not surprisingly, these contacts eventually fail leaving the clock in a non-working state. Unfortunately, replacement contacts are not readily available and are very difficult to repair reliably.

The Clocks 4 Classics Solution
Clocks 4 Classics have overcome this problem by using modern electronics to replace the failed contacts. A solid state infra-red sensor is used to sense the position of the balance wheel and a micro-controller chip uses this information to control the current to the solenoid coil. The rest of the mechanism is left untouched so that the clock looks and functions just like the original, retaining that all important tick!.

Some of the clocks that their kit fits:

AC Cobra
​Alvis TA14
Alvis  TA21, TC 21 , TD 21, TE 21
Alvis TC21/100
Armstrong Sidley (1938 - check model)
Aston DB2/4
Aston Martin DB Mk III
Aston Martin DB4, DB5, DB6
Austin A55, A56
Austin Cambridge
Austin Devon
Austin Healey 3000
Austin Princess 1100
Austin Westminster
Bentley Mk V1
Bentley R Type
Bentley S1, S2, S3
Bristol 403,404,405, 406
Citroen Traction Avant /  Light 15 (Slough built)
Daimler Conquest
Daimler V8,  V8 250
Ford Prefect
Ford Zephyr 6
Ford Zephyr Mk 2
Ford Zephyr Zodiac
Gilbern Invader (Not CTE type - please check)
Gordon Keeble
Humber Super Snipe
Jaguar E type Series 1
Jaguar E Type Series 1.5 (Early types only)
Jaguar Mk 1, Mk 2
Jaguar Mk 10
Jaguar Mk IV
Jaguar Mk IX
Jaguar Mk VII M
Jaguar S Type
Jaguar XK 120, XK140, XK150
Jensen 541r
​Jensen 541S
Jensen Interceptor (Early types only - please check)
Lotus Elan +2S
Maserati
MG Magnette
MG TC , TD , TD II ,TF
MG YA, YB
MG ZA,  ZB
Morgan (Flat Rad)
Morris 1800 (Check Type)
Morris Isis
Morris Oxford
​Morris Minor
Riley RM Series
Rolls Royce Silver Cloud SI, S II, SIII
Rolls Royce Silver Dawn
Rolls Royce Silver Wraith
Rover 12, 14
​Rover P3
Rover P4  (Jaeger type)
Sunbeam Alpine
Sunbeam Talbot 10
Sunbeam Talbot 90
Sunbeam Tiger
Triumph Roadster
Triumph Stag (Early Type with Smiths clock only)
Vanden Plas Princess (Early types only)
Vauxhall Cresta
Vauxhall Victor
Volvo P1800,  P1800 S (Smiths Type with large chrome bezel only)
Wolseley 15/50, 15/16, 4/44
Wolseley 680

They will also do the work for you if your clock has stopped working, or if the 18-page instruction manual has scared you to death. The tach kit is much simpler; only 7 pages of instructions.

I think I'll have to give this a try.

Cazalea

More posts: Aston MartinBentley MotorsDB4DB5DB6E typeJaguarLotusMaseratiP 1800Volvo

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