In the April. 1941 issue of Motor Sport AC Whincop wrote of his Bugatti experiences. In this informative article Capt CL Clark RA, does likewise, and with a moral, for he considers developing one make of car for club competitions by far the best approach to inexpensive racing, and gives many useful pieces of advice.—Ed.
These notes may be of interest as they outline, what seems to me to be the easiest way of going about racing in a small way. That is, by concentrating on one make, working up from the slower to the faster models and using the experience gained to do most of the work on the cars oneself. Although I made a point of recording the details of all work carried out on my Bugattis, these notebooks are not now available, and so I cannot offer here detailed information which might be of value to other Bugatti owners.
I became interested in the Sport while still at school—in the days when the 2 litre and “two-three” Bugattis were winning nearly every race that was held ; such an impression did they make that I have since owned nothing but Bugattis. The first was a 1924 “Modified Brescia” then 10 years old. The specification of this model is well known—the car itself was identical with the one tested by Motor Sport about that time. The long wheelbase chassis had only rear-wheel brakes and was fitted with high-pressure tyres, while the body was a narrow 4 seater. As soon as the car was purchased the body was removed and thrown away, and the engine and chassis stripped for examination and overhaul. The engine, which had recently been rebored, was found to be in good order. It had the late-type crankshaft with the front main bearing plain and the other two ball,—the “Full Brescia” cylinder block with dual plug orifices on the induction side, and a single SEV magneto driven from the vertical drive to the camshaft by a horizontal shaft. After the big-end bearings had been re-metalled and the 16 valves ground-in the engine was re-assembled and refitted. As it had been decided to build a new 2-seater body the gearbox was moved back 18 ins—the shaft connecting the engine to the gearbox being lengthened to suit, and the propeller-shaft being shortened. The steering column was also lengthened, thus giving a seating position just in front of the rear axle. The chassis was then fitted with a long bonnet and a short door-less body.
With the standard Zenith carburetter and low-compression pistons, the maximum speed, on the high top gear of 3.4 to 1, was about 72 mph, but, while the car handled well, the brakes were the limiting factor to performance. Very little trouble was encountered, there was some plug oiling at first due to somewhat worn inlet valve guides, but, this was overcome by providing improved drainage for the oil fed to the cambox. In an effort to improve the braking, the local breaker’s yard was visited and a front axle from a sports Lea-Francis was obtained. This axle had spring beds which allowed the existing Bugatti springs to be out-rigged (in the manner of the later models) by the fitting of a dumb-iron tie-rod and brackets to carry the rear shackles, while the Bugatti steering rod fitted straight on to the “Leaf” steering arm. With this axle installed the transmission brake was scrapped and all four brakes coupled to the foot pedal.
This gave an appreciable improvement in the braking department, and steps could then be taken to improve the performance. Twin SU carburetters were fitted, which gave a performance justifying the entry of the car for the second Wetherby speed trial.
The run up to Wetherby was marred by a series of oiled plugs—since the car had been remarkably free from this vice, it did appear as though the well-known Bugatti temperament had arrived ! This state of affairs persisted through the first climb, and it was not until the interval that my friend, who had been cleaning sets of plugs the whole of the very hot day, asked if I had been “playing about with the so-and-so magneto.” After I had assured him that I had had it off the day before to check it over, he grabbed the ignition leads, which “came off in his hand.” I had, of course, failed to tighten the set-screws which held the leads to the distributor block! After that the car went well, but my reputation as a tuner of motor cars dropped to a new low !
Shortly after this the Brescia was sold and a 11/2-litre Type 37 Grand Prix was purchased. This had, for a long time, been my ideal, it being one of Ettore’s more straightforward designs. This particular car was of 1929 vintage and was quite standard, even to being fitted with full road equipment, hood and sidesereens. The specification of this model may not be so well known and may bear being given in some detail.
The engine, four cylinders of 69 by 100 mm, has a fine, disc-type, crankshaft carried in five plain bearings, all bearings being lubricated under pressure by a large oil-pump driven from the nose of the crankshaft. On the earlier models jet feed was used for the big-end bearings, oil from jets in the crankcase walls being directed into grooves cut in the webs of the crankshaft. From these grooves the oil flowed to the. big-end journals. While .this system is suitable for low-speed engines, or for those fitted with roller bearings, it limited the maximum safe speed of this engine to 4,000 rpm. With the full pressure system the safe revs were said to be 4,500, but this could be quite safely exceeded for short periods. The cylinder block, with its fixed head, carries three valves, one large exhaust and two inlets. The camshaft is housed in an aluminium alloy cambox and driven by a vertical shaft at the front of the engine. This vertical shaft also carries a skew gear driving the horizontal shaft for the water pump. The valves are operated by fingers which pivot on tubes running the full length of the carnbox and which carry oil under pressure to lubricate the camshaft assembly. The valves are fitted with caps and clearances are adjusted by shims. Standard carburation is by a single Solex feeding through a two-branch, water-warmed manifold. Ignition is by a Delco distributor driven from the rear of the camshaft and at right angles to it.
Transmission is via the usual Bugatti multi-plate clutch contained in the small diameter flywheel, to the separate 4-speed gearbox, and from there by means of an open, solid propeller-shaft to the straight-toothed final drive. The chassis is the standard Grand Prix type to which the larger, 8-cylinder engines were fitted, although the front axle, while appearing to be the same, is solid and not tubular as on the more expensive models. The reversed 1/4-elliptic springs allow the axle to move fore and aft, the axle being positioned by means of short radius rods which run forward to the chassis frame, and all torque being taken by a long torque arm which runs alongside the propeller-shaft and is secured to the gearbox. The normal axle ratio for this model is 3.86 to 1 which, with the 5.00-in tyres usually fitted, gives a road speed of 21,1 mph per 1,000 rpm. Wire wheels are standard, brakes have the smaller diameter of 11 in, and are operated by an ingeniously balanced cable system.
During the winter, armed with information gained from “Bugantics” and experience of the car when it had been run on the road for a month or two, a complete overhaul was undertaken. The engine came in for most attention, for it was known that exhaust valves sometimes broke and that big-end bearings did not always stay in place. The reasons for these unfortunate happenings were perfectly plain—the valves broke because, being hollow, they only had a certain useful life, while bearing troubles were due to complete disregard of rev limits.
When stripped the engine was found to be standard, except for Martlett pistons giving a compression ratio of 6 to 1. The rivets securing the big-end brasses to the rods were found, in some cases, to have sheared, and this appeared to be a likely source of trouble in the future. These rivets were therefore scrapped, the rods and caps were reduced by 1/16th in, and brass shims were made up to trap the bearing brasses in place. The bearings were then re-metalled and fitted. In order to give a higher oil pressure the oil pump was moved from its original position and mounted opposite the water pump, taking its drive from the bevel wheel on the vertical drive shaft, and increasing its speed of rotation. New KE965 valves were made up, with oversize stems in order to utilise the existing guides, and Terry valve-springs fitted. Since magneto ignition was preferred a Scintilla was fitted in place of the coil system. The chassis required little attention, though the Bugatti shock-absorbers, which are not really adjustable, were replaced by Hartfords, those at the rear being transverse. All steering arms and rods, torque tubes, etc., were chromium plated and the body cellulosed black, with the wheels aluminium.
One further modification was made after the engine had been run. It was found that the supply of oil to the cambox was excessive, so adjustable needle valves were fitted to control the amount. When run-in the car had a comfortable road speed of about 85 mph and handled extremely well. It was used for normal road work and also entered for the Frazer-Nash CC Stanley Cup meeting on the Donington Inner Circuit.
For this meeting a single SU replaced the Solex carburetter, and in practice the car reached 90 mph. Acceleration was quite good and the way in which it handled gave complete confidence. But in the actual events things did not go at all well for, after two laps, boiling set in and it was found that the electrodes of two plugs bad melted ! That taught me not to use soft plugs for such work—a thing that I should have known before. The car was also run at Wetherby soon after—as a racing car since it had no starter—but the bottom gear of 9.5 to 1 made standing starts difficult and our times compared very badly with such ears as Moore’s GN “Wasp.” The same trouble was found at Saltburn—in the sprint events we seemed to sink into the sand rather than to proceed with the rest of the field, though we did manage a third place in one event. Throughout this period the car was used for ordinary running about and also went through the BOC Monte-Honiton-Carlo Rally without losing a mark, finishing sixth.
Attempts were next made to improve the performance, and new Martlett pistons giving a compression ratio of 7 to 1 were fitted. Discol fuel was used and there was a considerable improvement. A further pair of wheels carrying 4.00-in by 17-in covers, were obtained, to lower the effective axle ratio, and the car taken to Wetherby for the last meeting of the season. Here the alterations showed their worth, since second place was obtained in the 11/2-litre racing class.
Encouraged by this, a further overhaul was carried out during the winter. Since the car was in genuine use as a sports car it was decided to equip it with a starter and so comply with the specification of a sports car as laid down by the various clubs. It was found that the big-end modification had been completely satisfactory and, to make the crankshaft assemhly 100 %, the main bearings were reground and re-metalled. An almost new cylinder block was obtained, the existing pistons and valves being retained, and the engine carefully re-assemhled. Two short, separate inlet manifolds were made up and twin Solex fitted, twin SUs being prepared as alternatives. The standard oil filter was replaced by a large Tecalemit cooler-filter mounted in the airstream outside the bonnnet. The flywheel was fitted with a special starter ring and a starter was mounted on an extension of the gearbox lid.
When run-in, oil pressure was set at a constant 60 lb/sq in, and it was found that the temperature of the oil, thanks to the cooler, never exceeded 70 degrees C. The safe maximum engine speed of 4,500 rpm was now obtainable—the Solex carburetters giving rather more speed while the SUs gave the better acceleration.
In this condition the car was run in the first Wetherby event of the season, but only managed a second place in the 11/2 litre class. More tuning was done and the car entered for the Stanley Cup events at Donington. Practice showed a considerable improvement–113 mph with full equipment on the straight down to Starkey’s Corner. In the LCC Relay Race, setting off as first car of the limit team, a considerable lead was built up, and in the two other events for which the car was entered, second and third places were obtained. Encouraged by this, the car was entered for the two short races which preceded the Coronation Trophy event on the full Donington circuit. For this it was stripped of all touring equipment and 23 per cent PMS2 was added to the Discol normally used. The practice period was marred by rain but, being anxious to put in as many laps as possible, I very foolishly made my first acquaintance with the circuit when it was streaming with water. After a few laps to warm things up I pushed a stop-watch into my mechanic’s hand and asked him to time the next three laps. Intent on making reasonable times I believe that I left the road on every corner on every lap ! On one occasion a photographer had to leap very smartly over the straw bales at Coppice—and then I chased him some way up the escape road ! All in all I was very glad when those three laps were over, but when I returned to the pits it was to be greeted with the remark, ” How do you start this watch?”
In the actual events no one could get near the “works” Austins, but it was great fun. The Bugatti went well. Ignoring the rev limit in the excitement, I went up to 5,000 rpm in the gears and got 4,700 rpm in top going down to Starkey’s–about 100 mph—and was elated to pass a K3 MG “Magnette” which had started off the same mark. The things that stand out most in my mind, however, were, first : after leaving braking to the very last moment (as I thought) for Coppice Corner, being passed by Charles Martin in the “3.2” Alfa, on the inside still apparently going at full bore and having time to grin at me as he passed ! And, secondly, the way in which everyone managed to miss the driver of a Maserati who had stalled his engine on the point of Coppice Corner and was alternately jumping out to push the car off and jumping back to take cover !
After that the road equipment was refitted and the car used for touring until the next meeting on the Donington Inner Circuit. At this meeting the car, entered for both sports car and racing events, went well and managed several places. The most interesting race was one over 10 laps for cars of all types. We found ourselves on scratch with Mays’s 2-litre Alvis and “Bloody Mary”. Bolster, of course. shot away at the start and, having gained a considerable lead, dispensed with his bonnet, which came down like a falling leaf and took quite a lot of avoiding. After that we all three proceeded to run through the field, Bolster gaining a great deal on acceleration, losing some of it by motoring on the grass at the corners, while the Alvis drew away from me on the straight, but lost on the corners where the Bugatti was much more handy. We finished in that order after 10 very enjoyable laps. Next came a memorable week-end, a combined BOC/VSCC meeting at Donington on the Saturday and Wetherby “Open” hill climb on the Sunday. The Bugatti went “like a bomb” at Donington, winning two events, being second in two and taking two “vintage” awards. Carrying full road equipment, except for a silencer, 100 mph was touched on the run down to Starkey’s Corner, while the magnificent way in which it handled allowed places to be made up on every corner. After being driven home that night the Solex carburetters were replaced by the SUs, the small rear wheels were fitted and the next day the 11/2-litre sports class was won at Wetherby.
After this the car was sold, as I felt that I had graduated to something faster. This took the form of a late-pattern Type 35C -the supercharged, 2-litre, single-camshaft model. The car bought had a distinguished record on the continent which, of course, indicated a hard life, but unfortunately I could not resist trying it out at Donington before stripping it down. The inevitable happened. While going quite well as the scratch car, there was a bang and a cloud of smoke, and a rod came out. A very full winter of spare-time work ensued, the car being stripped right down.
The chassis of this model is, of course, the same as that of the Type 37, except that it has the magnificent tubular front axle and aluminium wheels, with the large brake drums integral. The engine, however, is very different in detail, the crankshaft being built-up with four ball and two roller main bearings and roller bearings for the big-ends. The two cylinder blocks, each of four cylinders, are of the same pattern as the Type 37 but lighter and of 60 mm bore. The cam box is in one piece and carries at the rear the ingenious drive for the magneto, whereby the position of the armature can be altered relative to the camshaft, thus giving advance and retard without affecting the optimum spark. The big Roots blower is driven from the nose of’ the crankshaft by a train of gears and draws from a large Triple-Diffuser Zenith carburetter. The first prohlem of the overhaul was the crankshaft. After some time a somewhat worn secondhand shaft was obtained. The fault, with the earlier editions of this type of shaft was that they were fitted with hollow rollers throughout. When these rollers had seen considerable service they appeared to become somewhat compressed (they resembled Hyatt bearings and were in no way solid), with the result that they skidded round their journals instead of rolling. This wore flats on the rollers and, in the end, caused the bearing to lock solid and rods to break. The later shafts were fitted with normal, solid rollers and were most reliable provided that the engine was first warmed-up slowly to thin the oil and prevent any chance of the rollers skidding. The correct procedure for the overhaul of these shafts was to send them off to Molsheim, but that sounded most expensive, and so the large, taper cotter-pins which lock the sections of the shaft together were pressed out and the shaft dismantled. The journals, rods, and roller cages were all carefully examined, oversize, solid rollers were made up by a local firm, the shaft was re-assembled and finally locked-up after being trued between centres of a lathe. The aligning of the shaft was, of course, a job for a skilled turner but, after some careful work, it was done with the required accuracy. This shaft was used for two seasons of racing and was then transferred to a sports engine, in which it ran some 4,000 miles—-so the roller-bearing shaft does not seem to be quite the bogey that it is usually made out to be.
After all components, including the supercharger, had been dismantled and overhauled, the engine was re-assembled with re-bored blocks and new Martlett pistons, giving it a compression ratio of 7 to 1. The Bugatti valves were replaced by solid KE865 valves, fitted with Terry Springs. The chassis was in good order. The axle ratio was 4.5 to 1, the lowest fitted. All steering arms, rods, etc, were plated and the body panels cellulosed the correct shade of blue.
It was decided to run the car only in hill climbs and sprint events during the first season, since these do teach both the tuning and driving of a car without incurring too much expense. The first event was at Prescott, but the combination of a partly-tuned car and an inexperienced driver (who was thoroughly frightened by such a hill) resulted in a pretty poor time. Next came the first Wetherby meeting of the season. This was much easier on the driver ; the car had been further tuned, and second fastest time of the day was recorded. And so the season went on. As the car was tuned and I got the feel of it, so times improved until we managed to get third places at Poole and Prescott and, at last, fastest time of the day at Wetherby.
Throughout the season the rev limit was kept down to 5,000 rpm (5,500 rpm is the official limit, though it can very easily be exceeded). The fuel used was Discol with 25 per cent PMS.2 added ; Castrol R oil was used and Champion R7 plugs. On the 4.5 to 1 final drive ratio 5,000 rpm represented about 80 mph in third and 95 in top.
For the next season the engine was checked over carefully and the compression ratio lowered to 6 to 1. With a view to running at Donington the axle ratio was changed to the more normal 3.8 to 1. In order to run the engine in wings and silencers were fitted and, amongst other runs the BOC Opening Rally was attended. For this season a 2-wheeled trailer had been made, the whole outfit being towed behind a V8 Ford. This proved a most comfortable and efficient method,
The season started well with fastest time of the day at Wetherby, followed by a third at Prescott. The car seemed now to have found its form—-5,000 rpm came up very easily. This now gave about 92 in third and 117 in top, together with good acceleration throughout the range. A return was therefore made to Donington for an Inner Circuit meeting organised by the United Hospitals Club. Starting from scratch in the first “allcomers” event, third place was taken after never as much as seeing the winning car, owing to the handicap. In the second such event the car was re-handicapped without my being told anything about it, with the result that I started with the same bunch of cars as before. After a grand struggle with a 2.6-litre Alfa and two 2-litre Bugattis, we managed to run through the field and cross the line first, only to be disqualified for starting too soon. This disappointment was somewhat mitigated by being awarded a cup for the fastest standing and flying laps of the meeting.
The car was handled with care (owing to the memories of our last visit !), but went extremely well and handled as only a Bugatti can. Between 115 and 120 mph was reached going down to Melbourne according to the rev counter.
Unfortunately, my TA unit went to camp for a month after this, and a number of events were missed. However, I managed to get leave to attend the Open Meeting at Wetherby. Here the car (and especially the driver) was outclassed by such exponents as Fame, Baron and Lemon Burton, but a run was made in under 30 secs, which was quite a lot faster than the old record, and only goes to show the effect of example ! After camp the car was taken down to Prescott and managed to win the 2-litre class (No, Mays was not there !).
Next came the Poole Speed Trials and the International Meeting at Prescott. At Poole only one run was made before it rained and, since it was the first of a number of runs, it was not made “flatout.” Being thoroughly frightened of going quickly in the rain, this time was not improved on, and we were lucky to get third place in the class, a fraction of a second behind Arthur Baron with the “3.3” Bugatti. The Prescott meeting was a good show, but not for me ! After some quite reasonable times in practice (and thinking of the bad tactics employed at Poole the day before) a really determined run was started. Going up to the first hairpin below Pardon Farm at quite a respectable speed, I attempted to change down to bottom to round the corner, only to find that there did not seem to be a gear available! I had, of course, been relying on the engine as well as the brakes, which were then fairly hard on, and was foolish enough to look down at the gear gate. The reverse stop had lifted and the lever was being pushed against the (Iuckily) blank side of the gate. When I looked up there appeared to be trees hanging over the radiator, so I put up a panic show on the brake pedal, which just stopped the car in time, but which also twisted the front axle between the off-side spring mounting and the swivelpin. So that was the end of that climb, the car being quite unmanageable on the right lock. Altogether it was rather a disappointing week-end.
Next came a rush to get the car ready for a meeting at Donington less than a fortnight later. The damaged front axle was sent away to be straightened, but owing to various delays, could not be ready in time. A secondhand axle was obtained the night before the event and fitted during the night. We arrived at Donington in time to do only the necessary minimum of practice laps and used them to make brake and shock-absorber adjustments. In the first race we were flattered by being put on the same mark as a 11/2-litre Maserati, with another of these cars and the BHW on scratch 3 sees. behind.
For the first lap all went well, but on the second lap the blower release-valve started to lift and, unwilling to risk damaging the engine, I retired. The race itself was marred by the death of Sir John Bowen, who crashed in the Maserati. As a result of this accident the meeting was curtailed. The cause of our trouble was found to be weak mixture. For sprint events the mixture was cut down as much as possible to avoid “gulping” when getting off the mark. For road-racing the mixture was made considerably richer to keep things cool inside the cylinder heads. In the excitement of changing the front axle this had been overlooked and the jets for sprint work left in the carburetter.
Of the two events which remained in the curtailed programme, one was a scratch event in which we took second place behind the BHW, and the other a handicap event in which we started from scratch and managed to win. And that, though we did not know it, was the last race to be run at Donington for a very long time. It is very much to be hoped that we shall see a lot of club meetings on both circuits after the war— they are such very good value. In fact, I wonder if we can hope to see a club organise a “Vintage Grand Prix” there, with, say, entries of cars of the types that ran in Grand Prix races between 1920 and 1930?
My regiment was at war stations before the next event for which we had entered was run and, later in the year, while on leave, the engine was taken out of the Bugatti and carefully stored.
Early in 1940 I was given staff duties which necessitated the use of a car, and so a Type 43 was purchased. This, it will be remembered, is a very sporting edition, consisting of the “2.3” Grand Prix engine in a somewhat longer chassis. Except for the sump and engine bearer arms and the increased stroke (100 mm instead of 88 mm), the engine is identical with that of the 2-litre, and this had great advantages when it was found that there was play in the rollers of the “two-three.” The crankshaft assembly, pistons and cylinder blocks from the Grand Prix car were fitted to the Type 43, and twin Zenith carburetters were fitted in place of the blower in view of the petrol restrictions.
This car was fitted with a very comfortable 2-seater body rather on the lines of an American roadster and was very fully equipped, even to the extent of having a radiator muff ! Some 4,000 miles were covered with the car in this state. 4,000 rpm could be reached, or 82 mph, with the 4.1 to 1 axle ratio fitted as standard, while no trouble at all was encountered. Towards the end of the year the urge to refit the blower could not be resisted, and so this was done, the jets of the triple-diffuser Zenith being replaced by adjustable jets which could be cut down for town work and quickly opened up for fast runs. In this state the car was not pushed, but 4,500 rpm was available, which meant a little over 90 mph. With a little tuning and decent fuel there seems no reason why this model should not do more than 100 mph.
On being ordered overseas this car was laid-up alongside the Grand Prix, to await the day when it will tow the GP to further events and, incidentally, act as a very useful set of mobile spares !
[This article contains many useful hints to Bugatti owners, but Capt Clark has kindly offered to help anyone in connection with Brescia and Types 35, 37 or 43 Bugattis, and, in view of his long experience with, and successful operation of, these cars, this offer should prove most acceptable. Letters can be forwarded.—Ed]