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Testing the Prototype

Bob Grice joined the Austin Motor Co. in 1925 as an apprentice and then specialised in the Experimental & Development Departments. During Herbert Austin's time he spent many hours with him at his residence, Lickey Grange, in developing and improving existing models. This work was always done away from the factory.

At the time of the launch of the A30, Bob Grice was Chief Experimental and Development Engineer at Longbridge and saw the car through the prototype stages. It was his responsibility to subject the original design to extensive rig tests and then to even more extensive road tests before approving it for full production. A change in design during the development period is not classified as a fault but should a modification be required after the car had been put in full production, then it would have been Bob who had to carry the can.

The prototypes were built in the Experimental Department and those involved had to sign a document saying that they would never discuss prototypes during their development. There were one or two sackings after leaks of information.

Much testing took place at the M.I.R.A test track near Hinckley and road testing took place in both England and Wales. When the model came up to the required standards in each country the prototypes were then put through further tests on the Continent. At a later date, the first six fully-tooled production cars were registered and taken on a full Continental test through the same terrain and countries of Europe as the prototypes.

Some of the prototypes were never completed, but were allocated for particular test war. One was allocated to the Belgian Pave and Washboard at M.I.R.A. Each car had a critical speed on the Washboard and with the A30 it was 25-35mph so instructions were given to test for 1000 miles on the Washboard at this speed. The car then went onto the Pave for a further 1000 miles. 1000 miles on Pave or Washboard is equivalent to the life of a car under normal road conditions.

Many brake tests were also carried out with this prototype. The car was taken up to 50mph and braked. This test would be repeated for about 20 consecutive stops in order to test for brake fade. Many different linings were tested in order to obtain the best anti-fade results and a 0.5G stop.

The second prototype was taken into Wales. Amongst other things this was to reprove that the linings were satisfactory as to their anti-fade properties. This was assured by driving around the Welsh Mountains e.g. at Bwlch y Groes and Alt y Bady.

It was on the third prototype that work proceeded to find the best distributor curve and engine power curves. The carburettor had been thoroughly tested on the test bed by working through different jets in order to achieve optimum efficiency and then the car was taken on the road to test both the carburettor and the distributor under road conditions. If the results on the road did not match up to those on the test bed then the distributor curve or the jets and choke of the carburettor were altered until satisfactory results were obtained.

The third prototype was also used to develop the steering as well as the shock absorber settings for bump, rebound and bleed in order to obtain a smooth ride. The prototype shock absorbers were adjustable and when a satisfactory setting was achieved they were taken off the car and put onto machines to establish the readings from which the actual shockers could be made.

The cross-shaft that operates the clutch was a bit of a problem as it used to knock badly (some still do!) Bob Grice remembers packing it with heavy grease to see what effect the would have, but it was of little help, and the oval plate that retains the inner bush was made of heavier gauge metal to hold the bearing more firmly. The inner bush itself was modified during production at chassis no 13,675 by replacing the solid bush with a rubber bush that had a brass lining with shallow pockets on the inside bore to help retain the lubricant and provide more silent operation. The clutch plate required a lot of development, particularly the clutch plate springs, in order to take out the chatter from the gears. Eliminating chatter on both drive and over-run took a long period of time. Borg and Beck produced clutch plates which were tested and sent back to them maybe a dozen times until satisfactory ones were developed. When a secondary plate had been found for the car, six identical plates were ordered and tested in six different cars. When everything proved alright, one of these clutches was taken out and stamped as the Master Clutch and was then sealed in a glass case. This was normal practice so that if during production there were problems with clutch chatter the supplier could be called in and the Master taken out of the glass case in his presence and checked against the supplier present standard. Master copies of the carburettor and distributor were retained in a similar way.

Malcolm Gardner, now of Zimbabwe, served his engineering apprenticeship at Longbridge from 1953 and considers himself fortunate to have spent a period in the Development and Testing department. He recalls that much of the testing in which he was involved took place at the M.I.R.A. testing grounds, and that the Belgian Pave was a great one for testing the suspension and chassis. He remembers driving the A30 with sand bags loaded into the boot in order to test the rear suspension and that the rear springs were the first to go. This resulted in experiments with stronger springs. The Dust Tunnel was also much used in order to test the amount of dust entering the car and boot, One must remember that Britain was now building cars with the export market very much in mind and so had to try and make cars that would be satisfactory under extreme conditions.

Malcolm remembers that the early A30 prototypes were very fast. Apparently they would easily top 90mph and so they had to be de-tuned before they went into production! Bob Grice explains that they were de-tuned in order to get better pick-up in top gear at low speeds and also to save petrol. The carburettor was fitted with a smaller choke. If a big choke had been left the engine would have been raced to death and would have had unsatisfactory life span.

Dan Clayton and Malcolm Gardner are seen opposite with two 4-door cars that covered 50,000 miles of testing in just 3 months in 1952. An incident in Wales reminded Malcolm that the very early A30s had loose bolts & nut holding the wheel on, as opposed to fixed studs and nuts. During the 50,000 mile test they noticed that the near side rear hub cap would fly off after about 200 miles due to the bolts undoing themselves and forcing off the hub cap. They would tighten up the nuts and set of again. They reported the matter to the Design Dept, and suggested fitting studs with nuts to hold the wheels on. They didn’t agree as it was going to cost an extra few shillings per car and they were working to a very tight budget. They designed a new type of wheel spanner giving more leverage and instead of managing 200 miles before the wheel came off they now managed 230! One day in Wales when the wheel came off it resulted in the car overturning. Luckily there was only minor damage and no injuries. It was found that the wheel had come off over the wheel stud holes, which had been enlarged by the continual tightening of the wheel, and hence the hub cap was still on the wheel. After that incident all A30s came out with studs and nuts which solved the problem.

There were some overheating problems with the prototypes which were finally solved by fitting a pressurised cooling system. The grille had also to be changed. Apparently in the very early prototypes the bars in the grille were much closer together. Side vents could have been added but this would have increased production costs so bars were removed until a satisfactory cooling was obtained and then the remaining bars were re-spaced to form the new grille.

Continental testing of both prototypes and production models was a regular occurrence. The tests took place each year in November & December and lasted six weeks. Bob Grice would fly out to meet the test party at certain points on the route and how long he stayed with the party would depend on how the tests were going. Both he and Gil Jones often had to fly back in order to keep other development work on the move.

The first Continental road test of the AS3 took place in 1951. Two AS3s, LOP 855 which had right-hand hard drive and LOP 854 which had left hand drive, were accompanied by three A40 Somersets for a complete test in France, Spain and Belgium. The party from Longbridge included Roger Lewis, Gil Jones and Bob Grice. Representatives from Zenith, Armstrong Patents and Lockheed were also present. They sailed from Newhaven for Dieppe and traveled south through France to Bordeaux and then on through the Pyrenees into Spain. Extensive testing took place in Spain, including dust trials on dirt and secondary roads in the Rio Tinto area and high altitude testing in the Sierra Nevada. The return journey was made through France and Belgium, the party taking the Ostend-Dover crossing.

The test results were largely as follows:

The unitary construction of the car was found to have created a structure that was rigid and showed no noticeable shake or deflection even under the worst of road conditions. The front seats were found to be comfortable for the majority of passengers and driver. The lack of headroom in the rear was mentioned but it was felt unlikely that larger passenger who require good headroom would be carried in the rear of the car.

Draughts from the front doors was found to be one of the worst features of the car. Test, were carried out to determine the places from which the draughts came and it was found to be generally around the edge of the removable door casing and between the bottom edge of the window and door. In addition there was some draught from the top of the window where the glass didn't fit properly into the rubber seal and a little from the outer edges of the door itself. During the main journey, there was little entry of dust, but during the special tests in the Rio Tinto area, it was found that dust entered freely when the front windows were dropped 3", With the windows closed there was no dust entry but neither passenger nor driver could carry on under these conditions due to lack of air. Dust also entered the boot, The heaters on both cars provided satisfactory amounts of heat but due to the draughts around the front doors the occupants were warm on one side and cold on the side nearest the doors.

The front spring pans became buckled in a similar manner to previous experience in England but it was thought that a minor modification to avoid concentration of the load on the inner edge of the pan would correct this matter. The rear springs were found to be satisfactory for rate and strength but too long in relation to body clearance and were fouling at the rear shackles.

The most serious trouble was with the road wheels. Apparently all of them would have fractured if preventative welding measures had not been carried out. Fractures had appeared in the Pyrenees after the wheels had been subjected to repeated side thrust in cornering in the mountains. After the test the wheels were constructed from a thicker gauge of metal. Both cars were fitted with 5.20 x 13" cushion tyres which were inflated to 23lb front and 26lb rear to suit the load carried. No failures occurred and wear was considered good with an average estimated life of 21,300 miles for LOP 854 and 15,000 miles for LOP 855. It was not found possible to account for this difference as the suspension of LOP 855 was stripped before measurements could be taken.

The cars were thought to give a remarkably good ride under most conditions with from pitch or bounce but the shock absorbers lost considerable resistance in the warmer climate and although the ride remained free from oscillation due to the damping effect of the front suspension, high velocity bumps caused some bumping-through and a substantial improvement in shock absorber performance was thought necessary.

The screw bushes on the lower suspension wishbones were found to have seized and on LOP 854 the seizure was sufficient to have caused shearing of the cotter pin. Further tests were carried out later to decide on the necessary modifications.

The gearboxes were found to be generally unsatisfactory but they were not of the latest type already produced which were fitted with stronger synchro springs and modified synchro cone angle.

The rear axle on LOP 855 was noisy on both drive and over-run. This appears to have largely caused by slackness in the threads of the set screws holding the Crown Wheel to the differential case.

The AS3 brakes were thought to be very good for all normal and average conditions, but in the extreme conditions of being heavily laden in mountainous districts the pedal pressure required became rather heavy.

The performance of the power unit was considered excellent even though both cars carried quite a heavy load which normally consisted of driver, passenger, luggage and spares.

Third gear was found to be the lowest gear necessary for negotiating the majority of hills and second gear was only necessary when climbing the steepest of hills and when speed was lost on hairpins. Comfortable cruising speeds in the region of 50mph were obtained and fuel consumption averaged 40mpg.

A con-rod bearing failed on LOP 854 after 4,700 miles but it must be noted that the engines fitted to both cars were not of the latest type that were fitted with larger size bearings. It was Gil Jones who ran the bearings and he well remembers that some of the others were not very pleased with him! However, Gil reckoned that he was there to put the car through its paces and find her weaknesses. One reason for his unpopularity was the fact that the car had then to be towed from Spain, right up through France to Paris. Apparently the Main Agent's in Paris was the only place the car could be repaired. Gil now found himself on the end of a tow rope behind an A40 for several hundred miles attempting to maintain the required concentration whilst peering through a spray covered screen. The car was driven carefully through the towns because this was easier than towing and also because it would not have done for the new Austin to be seen in such difficulties! The photograph below shows members of the test party showing concern for the state of health of the car's engine while Bob Grice approaches from the left of the picture.

Throughout the test, the oil consumption on LOP 855 was excessive at 1200mpg. There was a leakage from the front sump cork and from the region of the tappet cover but the amount of smoke emitted from the exhaust suggested that the bulk of the oil was consumed in the engine. Inspection of the engine later showed that the oil control rings and their grooves had worn more than expected and that the gaps in the oil control rings were rather excessive as were the piston skirt clearances.

Until the bearing trouble with LOP 854 it returned an oil consumption of 2000mpg. This appeared to be due to smaller skirt clearances and the fact that the compression rings were a better fit. However, this engine showed more wear, the cylinder bore wear being an average of .002" for 4900 miles compared with .0016" for 9000 miles on LOP 855. It was noticed that maximum cylinder bore wear occurred at No1 cylinder and this appeared to be tied up with water circulation condition.

Timing chain rattle was found to be excessive on LOP 854 and quite bad on LOP 855. Final inspection showed a massive slackness in the mains but the noises ceased to be due to misalignment of the camshaft sprocket and crankshaft sprocket, causing side contact of the chain on the teeth of the sprockets.

The oil filter removed from LOP 855 after 8,000 miles was completely blocked and even though the oil was changed at 4,000 miles it contained too high a percentage of solids. The by-pass valve was also malfunctioning. Further tests were later carried out in order to determine the life of the oil filter.

Head distortion on the two centre exhaust valves was excessive and all the exhaust valves were pitted. A cylinder head with modified water circulation between the two centre valves was produced to overcome this trouble.

When reading the above it is essential to bear in mind that this was the first Continental test of the AS3 prototypes and as such was expected to show up the need for design changes in several areas before the car went into production.

As mentioned previously, production cars also went on regular Continental tests, but a well as that every car that left the factory was first road tested by taking it over Rose Hill to Rednall. 80% of the cars turned round at the Hare & Hounds in Rednall whilst the remaining 20% carried on to Lickey End before returning. All cars were adjusted as necessary whilst out on tests.

Once a week a car was picked off the production line for oil consumption tests. The car was taken out for a 20 mile run to warm up the oil and the oil was then allowed drain for 20 minutes into a container which was carefully weighed. The oil was then put back into the engine and the car set off on a 200 mile trip from Longbridge travelling via Kidderminster and Ludlow into Wales. The car would set out at about 8.15am and would return in the afternoon whereupon the oil was again allowed to drain for 20 minute before weighing in order to determine the amount used. The idea was to ensure that there were no complaints about heavy oil consumption and as a check to see that there were no slip-ups by those building the engines. For example there was an occasion where the piston rings had been fitted upside down. In such a case each car from the same batch would have its engine changed and all the engines would be subsequently checked out. It seems that later on tests became much less strict and one can certainly think of models that would have benefited from the Gil Jones/Bob Grice treatment. It is quite obvious from the talking to several Longbridge men that Bob Grice is still remembered as a 'very professional, no nonsense Head of Testing.'

© Reproduced by kind permission of the author, Barney Sharratt

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