MOTOR RACING IN THE ISLE OF MAN
MOTOR RACING IN THE ISLE OF MAN NOT quite" thirty years on," but what -a…
A Visit to Solihull to Study the Manufacturing Methods Applied to a Popular British Quality Car
SINCE we road-tested the Rover 90 (see MOTOR SPORT for September, 1956) and drove a Rover 105S to Monza and back last year via France and Switzerland (an account of this journey was published in MOTOR SPORT last November), we have had a high opinion of these British quality cars.
Last month we paid a visit to the factory to study some of the ways in which the Rover Company builds quality into its products.
During what was left of the morning after we had driven up to Solihull along the narrow, lorry-bound A 41 road, Mr. Peter Wilks’ assistant took us to see the Rover assembly line. This is notably compact, the assembly factory at Tyseley being far from vast, as car factories go. The line is continuous, in the form of an oval. Rovers gradually taking shape as they move along it, parts and components keeping pace with the cars in trays and containers that move beside the assembly line at the same speed as the cars. The chassis frames arrive from John Thompson Motor Pressings Ltd. for final machining at Solihull, and these frames are lowered onto the line as the first stage in tar assembly. Incidentally, so rigid is the Rover frame that six rubber-insulated body mounts are attached each side, the body thus being very largely relieved of having to act as a stiffener for the chassis.
Right from the start of our ” tour ” we were impressed by Rover thoroughness, for the first thing we saw was the spring-testing machine. On this every coil-spring used in the Rover i.f.s. system is fully compressed to reveal possible flaws, after which the spring is compressed to the space it occupies on the car and its strength read off on a big Avery dial. Each coil-spring must show a minimum of 1,700 lb./sq. in. and springs are paired, so that a slightly stronger spring is fitted on the driver’s side of the car compared to that on the opposite side, to ensure a level ride as the springs settle. For example, a 1,722 lb./sq. in. spring would be paired with one of 1,732 lb./sq. in.. the latter going on the driver’s side. The same method is adopted with the leaf-springs used at the back of the car, a code reference being painted on the springs to ensure such assembly.
We were shown the liberal use of rubber insulation employed in the Rover chassis. The front suspension radius-arms seat on rubber, rubber rings are fitted under the coil-springs, and rubber insulates the back springs. The complete i.f.s. assembly is first lined-up correctly on a special jig and the rear leaf-springs are liberally greased before gaiters are fitted to them.
It is attention to detail that distinguishes the quality car from the mass-production product. On the Rover all nuts and bolts are Parkerised to rust-proof them, brake and fuel lines are, wherever possible, attached to the top of the chassis frame, and clutch and brake pedals are mounted on a common spindle, very short and stiff, to obviate rattle and looseness.
When inspecting the Rover chassis the steering idler arm is seen to be a particularly nice alloy casting, with precision-cut splines.
As the chassis nears completion the required engine-60, 75, 90 I05S or 105R, complete with gearbox—arrives on an overhead gantry to be dropped into place. The control system ensures the correct sequence and number of different type engines for the daily output, and all the operatives have to do is to install the engine to hand. The single assembly line takes bodies from the paint-shop, these moving along for parts and trim to be added, down one leg and back along a parallel leg, until the body is lifted by crane for dropping on the chassis. About a minute or less, and two operatives, suffice to mate body and chassis. Each body-shell has been washed in paraflin to remove oil and grease, then washed in acid and water before the rubber sound-proofing solution is sprayed on. Five separate coats of primer are applied and rubbed down before two coats of the enamel are applied, wet on wet, and baked. All edges subject to slamming receive an extra coat. Incidentally, as Rover private cars grow on this single assembly line, completed Land Rovers receive their final cheek on an adjacent line.
The seats in the Rover bolt to the chassis, not to the body, and so there is space within the shell, after it has been attached to the chassis, for operatives to fit the remaining mechanical parts. Handbrake ratchets receive a generous dollop of grease, steering pivot oil reservoirs are filled, likewise the steering box, before the chassis leaves the line. Rovers have, of course, only four grease nipples. Radiators are fitted after the body has been lowered onto the chassis.
The i.o.e. Rover engine has a very imposing alloy cylinder head, the integral water passages and manifolding necessitating a complex casting, which is perhaps the most expensive part of the power unit.
The bodies are supplied by Pressed Steel Ltd., but are painted by Rover in black or in the many duo-colour schemes now available. Incidentally, the darker shade can be had above or below the waistline, as the customer prefers. Rover do all their own trimming, make the frames of the fully-adjustable front seats, and at final inspection each car is rubbed down, cleaned, and finally Simonised.
We were delighted to note the care taken over finishing the bodyshells. Rubber solution is applied to the interior, carpet felt is firmly glued down, and much use is made of Bostik solution to waterseal gutters, valances, fuel-filler door, etc. If specified by the customer the underside of the car can also be undersealed. Careful tests are made to ensure that each part of the body is truly waterproof. The transmission cover is undersealed beneath and carries sound-proofing above. The head-lining of the body is now of washable plastic but it is characteristic that Rover were reluctant to abandon a felt head-lining and did not do so until they had satisfied themselves that equally good sound-proofing was obtainable with plastic and that a ” cold ” effect would not be imparted thereby.
Alter the steering column has been fitted the seats follow and the cars are then trimmed, the trimming shop being on the opposite side of the road to the assembly shop. The bulkhead of the body is lined with good quality felt, and an interesting detail is that the unusual-shape, rigid, spring-steel gear-lever has slots on its mounting ring so that it can be moved away from or towards the steering wheel to meet individual requirements.
Bodywork details show similar ingenuity. The front tamper of a Rover contains some 48 separate parts, and particularly ingenious are the stainless steel rubbing strips, these constituting the broadest part of the body, thus protecting it from paint scratches which careless parking or a mild error of driving judgment would otherwise incur. The door-switches that actuate the interior lighting are beautifully made, by Lucas, but to Rover’s own design. The facia is of solid West African walnut and the lower rail of the facia likewise, polished by girls so that an individual grain is discernible on each car. The corner fillets for this facia have to be of alloy to obtain the correct curves, but a wood-veneer is cleverly applied to the metal, snatching the real woodwork. The two locker lids are likewise of polished walnut, with concealed hinges in the best cabinet-making manner, and the instrument panel is hinged to a rigid metal frame for easy access to the electrical wiring, etc. The wooden window frames are first strapped to the doors to locate them and then secured with self-tapping screws, a job that obviously has to be done by hand in the best traditions of craftsmanship.
The slide-out rubber-lined tool tray is another instance of wood trim done in the Rover works. The beater controls are made by Smiths; but to Rover’s own specification. The radiator grilles are chromium-plated but have contrasting slats of polished, rust-proof alloy, unplated.
Our visit was necessarily brief but in the space of an hour we began to appreciate how seriously Rover build quality and long life into their cars. After when we learnt something of how each engine and car is tested and of the infinite care taken to test materials and check engine assembly, our admiration reached fresh heights. Here it should be explained that the Tyseley Group of factories, taken over by Rover in 1920; now supply all the mechanical components for the cars. The total floor space is 672.020 sq. ft. and more than 3,620 people are employed there, working a five-day week, the engine-test shops, however, working right round the clock. The Springfield factory manufactures all experimental and development items and also tarries out complete reconditioning of the Groups machine tools. The Ryland Road factory supplies steering and suspension parts and makes non-current spare parts. The Perry Barr factory sends finished axles and transmission units to the Solihull assembly shop, while gearboxes are built at the Percy Read factory and sent to the engine factory at Tyseley, from which, also, all planning, jig and tool design, etc., is controlled.
Rover employ a rigid inspection system for raw materials and outside-supplied components. For this purpose they employ proportion of inspectors to operatives in the region of 20 per cent., have their own laboratory, and insist on test-pieces being taken from castings before they are machined. Castings are bought out, as Rover do not possess their own foundry, but they do all their own machining. Transfer cylinder-block machining is used for Land Royer engines but not for the car engines. Every connecting-rod is inspected for bore size and ovality on an air gauge, to half-a-thousandth of an inch. Starter-ring teeth are hardened by electrically heating each ring to 850 deg. C. and then quenching in water, an operation carried out automatically in a special cabinet. Gudgeon-pins are graded after machining to 1/10-tihousandth of an inch, camshafts are hardened both in the furnace and by the new gas carburising process, and components such as rocker-shafts, etc., are crack-tested. Pistons and connecting-rods are checked and graded in special pressurised rooms kept at an even temperature. Sets of six pistons all of identical weight are made up, five grades being recognised, within two drams, and every connecting-rod is balanced and the gudgeon-pin bore checked to within half-a-thousandth of an inch. Every valve seat is individually ground-in, tested by blue-ing, then tested again with petrol under compressed air.
After assembly the oil-gallery or each engine .undergoes a pressure check. In these and many other ways is the reliability of the Rover engine ensured.
Perhaps the most interesting aspect of this engine testing is the care taken in balancing all the rotating parts. An ingenious machine, designed by Rovers themselves. enables out-of-balance forces to be measured electronically via steel tapes, as a complete engine is mounted on slave mountings in the machine and electrically rotated. The 105R engine is balanced to ¼ oz./in. a task which can occupy an hour, as weights are added to clutch and/or crankshaft damper to eliminate out-of-balance forces. Every engine goes through this effective check ½ oz./in. being required from all types other than the 105R.
Prior to this flywheels have been checked for balance on a Jackson and Bradwell electronic balancer to an accuracy of 1 dram at 6-in. radius. Gearboxes are meticulously assembled, the gear cutters compensating for changes under beat treatment, and ground and crown-shaved gears being paired up after lest. Girls lightly shine each gear tooth to obviate burrs. Each gear-cutter is profile checked at each change of hob, and every day sample checks are made on finished ground and shaved gears. Every gearbox is tested, not in a flash run up, but for five minutes while motored in drive and overrun by a 50-h.p. electric motor.
We had this explained to us by Mr. G. H. Jeans, who then took us to see the final engine tests. Every Rover car engine goes on Heenan and Frounde water brake—there are 45 of these—for a period of five hours. Land Rover engines are tested for 2 hr. 20 min. For 4½ hours the engine is run on coal gas, then on petrol. During the entire time upper-cylinder lit is metered into the engine and it is continually supplied with clean oil direct to the oil pump, a slave sump merely acting as a drain. By this method no swarf or dirt from a new sump can be carried into the engine: the oil is maintained at a constant temperature, so that engines tested on Monday morning receive the same oil as those run on a Friday night.
It is considered best to check power output at 3,000 r.p.m., at which speed reliable figures are obtainable. At this speed the 2-litre Land Rover engines must give 38-40 b.h.p., the diesel version 40-41 b.h.p., the Rover 60 engine 48-51 b.h.p., the 75 a figure of 53-54 b.h.p. the 90 engine 64-67 b.h.p. and the 105 between 71 and 73 b.h.p.
In another shop there are live more water brakes, used for endurance engine testing. Tests of up to 700 hours, or even to destruction, are made at every change in specification material—at the time of our visit a starter ring was being subjected to repeated starts by all automatic means.
Finally comes the road test. This is carried tout on Rover’s own road circuit and every car and Land Rover is submitted to it. Two independent drivers test each car, and although routine tests cover about two laps in the hands or the first driver and three laps by the other, a total of 12-15 miles, if defects are found anything up to a week may elapse before the car is passed out. Such items as tyres out of balance. We did a lap with the senior tester in a 105R which had defaulted in respect of engine vibration and a reluctant automatic transmission change-up.
Only this extremely thorough testing of components, engines and the completed cars satisfy those responsible for maintaining Rover reputation. Even then every car is-put on a “bump machine” in a sound-proofed bay so that squeaks and rattles, if any, can located and rectified.
In spite of the care taken at each stage of assembly, Rovers attained a useful output of cars. We have been forbidden to disclose the daily output but, in the last ten years, Rovers claim to have built 200,000 Land Rovers, and at least one car to every three Land Rovers. As we have explained, the five different cars are assembled on the same line and it is common knowledge that the 90 and 105 the more popular models.
It is pleasing indeed to find Britain still building fine motor cars the highest standards—at Rovers they obviously consider durability and silence to be as important as performance. Under the circumstances, the fully-equipped Rover 90, for example, at £1,499 17s., inclusive of purchase tax, is not so expensive as it might seem at first sight. Indeed, we have frequently cited it as offering excellent value for-money. After having seen the conscientious care that goes into every facet of Rover manufacture and testing, we readily endorse this opinion !—W. B.
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