Shock-Absorbers

The design and manufacture of shock-absorbers (or dampers as they are more popularly known) have undergone a number of changes since World War II, not the least of which is the increasing use of the telescopic damper, and present developments indicate a strong trend towards the use of air as a suspension medium. In this review we have concentrated on those shock-absorbers which are available to the general public as replacement items. This will be especially valuable to owners of pre-war cars on which the existing shock-absorbers are now out of production.

Andre

The manufacturing rights of Andre shock-absorbers has been teken over by Woodhead Monroe Ltd. Details of this equipment will be found in the feature dealing with Woodhead Monroe shock-absorbers.

Armstrong

Armstrong shock-absorbers and suspension units are manufactured in six kinds. i.e., lever type, adjustable lever type, telescopic and adjustable telescopic, telescopic suspension units and adjustable telescopic suspension units.

As proof of their popularity they are fitted as original equipment on the following British cars, as well as being manufactured under licence on Continental vehicles: Armstrong Siddeley, Aston Martin, Austin range, Bristol, Cooper, Daimler, Elva, Frisky, Humber, Lotus, Lola, M.G., Morgan, Morris range, Peerless, Reliant, Riley, Standard, Sunbeam, Triumph and Wolseley. Their racing record has been proved on the majority of successful British racing cars: on Cooper cars, which won the 1959 World Manufacturers’ Cup for Formula 1 cars, on Aston Martins, which won the 1959 World Sports Car Manufacturers’ Championship, as well as on the Austin Healey Sprite and M.G. cars which broke the International records.

The basic lever-type shock-absorber is a hydraulic double-acting type, working on the principle of pumping oil backwards and forwards between two cylinders through suitable valves set to give the required amount of restriction in each direction. This design has the advantages in that all the working parts are submerged in oil.

These adjustable lever-type shock-absorbers provide a means whereby the degree of damping may be readily varied to suit particular requirements such as variations in weight, for competition or for racing purposes. They are manufactured to fit the rear end of most popular cars used for competition work, replacing existing initial equipment without modification to the chassis.

Armstrong have developed a design of telescopic and adjustable telescopic shock-absorbers which, besides having unique features, is extremely efficient, uses a minimum number of parts and is of robust construction to give long service life.

Adjustable models are manufactured for Cooper cars and are being manufactured as conversions for competition and rally work on popular sporting cars.

Both telescopic spring suspensions and adjustable spring suspensions are now used extensively for racing purposes and have proved themselves on Aston Martin, Cooper and Lotus cars, as well as on many others. They consist of a road spring and telescopic hydraulic damping unit, manufactured as a compact suspension unit. Different springs can be interchanged to give alternate spring rates, and in the case of the adjustable models the damping can be adjusted for various types of races and tracks.

Armstrong technical representatives attend all main International and approved National events and are available to advise and help on practice days. The Service Department at Beverley is always at the individual customer’s service (Telephone: Beverley 82212) for advice on details of any model. Prices may be had on application.

Armstrong Patents CO., Ltd., Fullord, York.

De Carbon

The French-made de Carbon damper appeared on the market in 1954 and has already gained a formidable reputation, being manufactured under licence in Germany, Spain, Italy and the U.S.A., and fitted to Mercedes-Benz, Dyna-Panhard cars and Pegaso and Daimler-Benz lorries as standard equipment. They were used on the three Monte Carlo Rally-winning 220SE Mercedes.

As can be seen from Fig. 1, the de Carbon damper combines both the hydraulic and pneumatic principles, the chamber at the top of the damper being filled with gas and separated from the oil by a free-moving piston. The hydraulic operation follows normal practice. On the road the gas chamber will take small road shocks but when major bumps are encountered the piston will move through the oil. It is claimed that the problem of fade is overcome, as when the damper begins to heat up the gas in the top chamber will expand, allowing no aeration in the oil.

Conversion sets are available for the following vehicles: Alfa-Romeo, Borgward, Citroën, Fiat, Ford 100E, Hillman Minx, Opel, Panhard, Peugeot, Renault Dauphine and Fregate, Riley 1.5, Simca, Singer Gazelle, Sunbeam Alpine, and Rapier, Volvo, Volkswagen and Wolseley 1500. For these models each damper costs £4. For the following models dampers are available at £4 10s. each: D.K.W., Humber Hawk and Snipe, Porsche, Rover, and for the following at £5 5s. each: B.M.W., Facel Vega, Jaguar, Lancia and Mercedes-Benz.

The sole concessionaire for Britain and many of the Commonwealth countries is the Alexander Engineering Co., Ltd., who will be pleased to answer individual inquiries, and for people who fit these dampers to competition cars the Alexander racing van is present at many of the major meetings.

Alexander Engineering Co., Ltd., Haddenham, Nr. Aylesbury, Bucks.

Girling

The current Girling damper is the CSV, which was introduced in 1959. This is made in 1-in. and 1-3/8-in. sizes, and it is claimed that this is the first maintenance-free damper in Europe, the problem of fade having been eliminated. As can be seen from the foregoing, most of the other manufacturers also make this claim! Nevertheless, as we have seen for ourselves, Girling Ltd. have gone to great lengths to ensure that their new CSV model will be as perfect as possible.

The damper engineer has many problems to face and when he has achieved perfection in one way he may well have emphasised an undesirable feature. This was illustrated to Girling by Jaguars when they tested the CSV dampers on a 3.4 model. The settings were perfect and gave an excellent ride, but over large bumps they gave an audible hiss as the fluid transferred – something which would never do for Jaguar owners. So Girling designers had to set to and eliminate the noise. That they did so effectively is proved by the fact that CSV dampers are used on several Jaguar models. They are also used on various Humber and Hillman cars.

Although externally similar to previous models, the CSV incorporates a number of improvements, including the piston and the piston rod, which is now hard-chromium-plated to ensure long life. The CSV is of completely welded and riveted construction throughout, thus sealing it against the ingress of outside matter. It is mainly intended as original equipment for new vehicles but the company will be pleased to advise on special installations.

Girling Ltd., King’s Road, Birmingham.

Koni

A relatively new name to British motorists is Koni, but one which is fast gaining a reputation almost equalling that of the legendary de Ram shock-absorber. In 1957 the Dutch firm of Koni, situated at Oud-Beijerland, celebrated its centenary, having been formed in 1857 by Mr. A. de Koning when he opened a saddlery. His son joined the firm at about the same time as the car appeared on the roads and they quickly realised the potentialities of this new vehicle which threatened their business of making saddles, horse collars and so on.

They transferred their attention to repairing of car hoods and bodywork, but as the years went by they turned to various motoring accessories, such as radiator blinds, special car trunks and a spring gaiter. It was not until 1932 that the first Koni shock-absorber was made, and in 1947 the first hydraulic telescopic model made its first appearance. Even now the shock-absorber accounts for only a part of Koni production, such items as electric car lifts, jacks, cranes and car heaters forcing the company to build eight different factories.

The existing Koni models are fitted as standard equipment on B.M.W., Porsche, Frazer Nash, Ferrari (including G.P. cars), and the Donglas 4/4 Pathfinder, a special-purpose cross-country vehicle. In addition to this, stocks are held of special dampers for Cooper-Climax F.2, all the Jaguar range, including the “D” type, Lotus, Lister-Jaguar and many other competition cars. Dampers can be prepared for almost any type of car or lorry that is capable of having them fitted. Obviously on certain cars which have been designed for the lever-arm type of damper there is invariably little room left to fit the longer telescopic damper. In some cases special brackets are available to mate the Koni to particular cars but in a very few eases it is impossible to fit them under any circumstances. The United Kingdom Agents, the Postland Engineering and Trading Co., Ltd., are happy to advise on special installations if full details are given about the car. For those who fit Koni dampers to competition cars the Service Van attends most of the major meetings throughout the country, from which advice and service is readily forthcoming.

The “Special D” shock-absorber is basically similar to other telescopic dampers but the manufacturers claim that by virtue of all parts being machined from the solid to close tolerances, with rigorous tests at all stages of production, that it will have a trouble-free and long life. Each damper is guaranteed for 19,000 miles or one year, whichever is the shorter. The main advantage of the Koni is that it can be removed front the car when signs of wear are shown and quickly adjusted. Alternatively a choice of six different settings are available to alter the characteristics of the damper.

Postland Engineering & Trading Co., Ltd., Crowland, Nr. Peterborough, Northants.

Newton

Newton and Bennett have ceased manufacture of all car-type shock-absorbers in favour of a larger unit for commercial vehicles.

Spax

Another post-World War II firm, Spax have recently introduced the VariFlo type 89 and 100 adjustable dampers. These are double, piston lever-arm type dampers which are designed to be interchangeable with a large number of other makes, particularly some of the obsolete pre-war types.

The body is of die-cast alloy, carrying the cylinders and the mounting points. The pistons are actuated by a rocker shaft and connecting rods, the valves being retained in the base of the body.

The type 89 is easily adjustable by means of a click-action screwhead which can be turned with a screwdriver. This gives quite a large range of adjustment for different vehicles or even for different operating conditions on the same vehicle. It is claimed that the type 89 will fit 79 per cent. of present-day cars, while the type 100 is suitable for the front suspension of certain Austin, Austin Healey and M.G. models. Prices vary from £2 12s. 6d. for the type 89 unit to £4 6s. for the type 100.

A special technical department is operated to cope with inquiries from “special” builders and people who wish to convert their cars to VariFlo dampers.

Spax Ltd., 61, Fortess Road, London, N.W.5.

Universal Dampers

Universal Dampers manufacture both lever-arm and telescopic-type dampers, the former being named the Rotoflo and the latter, the Teleflo. The Rotoflo has only one moving part, which is the central spindle, and the damping medium is a non-liquid “gooey” material which retains many of the desirable aspects of the hydraulic damper without the large number of moving parts in a telescopic type.

For light cars models A1 and A1/338 are available, and for heavier cars and commercial vehicles model A2 is used. Conversion sets are available for most British and Continental cars, the prices ranging from £3 18s, to £7 10s. per pair. Universal Dampers operate a special department for answering queries on these dampers.

The Teleflo strut-type damper fondles modern practice but it is claimed that the damper is completely free from aeration and fade because air never meets the damping fluid. Air is retained in a rubber sac at the base of the damper. Thus when the piston rod enters the cylinder a displacement valve at the bottom lifts to admit fluid to the reservoir and the rubber sac distorts to accommodate it. On the rebound the reverse process occurs, so that air never comes into contact with the fluid.

The Teleflo is fitted to certain Standard and Jensen models as standard equipment, while special models were used on the Connaught F.1 racing cars. The same department offers guidance and help in obtaining the best model for your purpose, either Teleflow or the Rotoflo. They are priced at from £2 5s. to £2 15s. each.

Universal Dampers, Railway Road, Shirley, Solihull, Warwickshire.

Woodhead Monroe

This company commenced the manufacture of telescopic shock-absorbers only at the end of World War II but has already built up a large market in Britain and the U.S. A. The company supplies all the original shock-absorber equipment to the Rover Company and also provide equipment for Triumph (front suspension on the Herald), Hillman Minx, Humber Super Snipe, Morris Cowley and Oxford, and the Riley Pathfinder.

The Woodhead Monroe damper is made in three main types, the 1-in, bore for most passenger cars, 1-5/8-in, bore for heavy-duty work on large cars and commercial vehicles, and 2-in. bore for use on very heavy vehicles and railway rolling stock. Standard replacement dampers are priced at £2 2s. each for the 1-in, size and £3 12s. 6d. for 1-3/8-in. bore. The company also manafactures “fluid cushion” suspension units which are basically similar telescopic shock-absorbers incorporating coil-springs within the body of the damper. These are especially useful for “special” builders who want a simple suspension medium with only two mounting points for each complete suspension unit. These retail at £4 10s. each and Woodhead Monroe operate a department to give advice on correct settings and so on for individual cases. A special suspension kit for the “perpendicular” Ford Popular is marketed at £15 15s., which includes all brackets and a special rate rear transverse sprine.

Of especial interest to owners of vintage cars and many other pre-war car owners is the fact that the Andre Hartford friction damper and Andrex TE lever-type dampers is now manufactured by Woodhead Monroe. The friction disc Andre Hartford shock-absorber, which was first used in the 1920s, is still produced at the Ossett factory and full spares and service facilities are still available This also applies to the Andrex adjustable lever-arm damper and the famous Telecontrol system with its fascinating regulator wheels and gauges which control the stiffness of the dampers. It is encouraging to see that a firm is willing to carry on with the manufacture of these dampers when the demand is very limited.

Woodhead Monroe Ltd., Moorcroft Works, Ossett, Yorkshire.