Maclachlan Austin - 80 Years old and still racing

Story, photos and a brilliant video by John Sutton 

Above: The Maclachlan Austin at Silverstone (Thanks to Rupert Lloyd Thomas for revised caption. See footnote at end of article.)

This amazing little car started its life as a Gordon England “Brooklands” model and was bought new by R. M. Papelian in 1926.  He took it to America where it raced successfully against much larger cars and created a lot of favorable comment in the Press under the heading “Pint sized auto with speed to burn”.  It was pictured with the caption “This amazing little auto makes 80 miles to the hour and 40 to a gallon of gas”. 

Having suitably impressed the Americans the car was returned to England and purchased by A. N. L. Maclachlan (known as Mac).  At the time Mac was up at Oxford and having entered the Inter-Varsity Speed Trials was looking for a faster car than his then current tuned Austin 7 “Chummy”.   

I take up the story from Mac’s article in Motor Sport of November 1945. This was his first real racing car and he was thrilled by its performance.  With the wings removed and the aero screens folded down it would do a genuine 80 mph and would run up to 5,700 rpm in second which was about 55 mph. 

The Gordon England “Brooklands” model was available to the public following successful development on the track.  The doorless bodies of these “production” cars were made by Boyd-Carpenter in his coachworks and were very light and flimsy.  A friend of mine, Bill Alderton, had one from new and he recalled that the body fell apart after about 18 months of road use.  It was an ash frame to which light aluminium panels were attached with panel pins.  The panels were butt joined over the ash and the join covered by a half- round aluminium strip.  They had a full undershield and the bulkhead between the engine and passenger compartment was made of leather!  The chassis were slightly lowered and the sports springs had zinc interleaves to cut down the friction.  Hartford shock absorbers were an addition.  The 750 cc engines were tuned with a very high lift camshaft which limited the revs and a special cast iron cylinder head which raised the compression ratio to 5.45 to 1.  The crankshafts were converted to a pressure feed oiling system and a rev counter drive was added to the front of the camshaft. The exhaust system emerged from the near side of the bonnet and ran outside the body with a regulation “Brooklands” expansion box and fishtail which made the car look very racy.  The back axle ratio was 4.4 to 1 on 19 inch wheels. 

Above: As it is today	Above: As it was then	Above: Early stages

After using the car on the road for a short time Mac started preparing it for competition.  The engine was de-carbonised and the valve ports and cylinder head were carefully polished.  All unnecessary weight was taken off the car and after testing to get the best ignition and carburetor settings the “Tiddler”, as it was now known, was ready for the Speed Trials.  His efforts were rewarded at Ewelme Down where it made fastest time in the 1100 cc class, with a time of 51.8 seconds, against a fastest-time-of-the-day of 45 seconds. 

Youthful enthusiasm and lack of experience of rev. limits soon resulted in a broken crankshaft.  Fortunately it broke across number 2 big end journal and the only damage was to the white metal bearing.  A visit to Laystalls produced a new crankshaft together strict instructions not to exceed 5,000 rpm.  Having learnt this lesson well Mac never broke another crankshaft in the Austin. 

The car continued to be used as everyday transport apart from one or two trials, whilst Mac was apprenticed to Thornycroft at their Basingstoke works, after coming down from Oxford University.  However competition was not possible as he could not get time off.  I recall my apprenticeship for Vickers Armstrong at Brooklands where we worked from 8.00 am until 6.00 pm on week days and 8.00 am to noon on Saturdays with evening classes as well.  Those were the days!  He did manage to do the London-Land’s End Trial with a friend in 1928 and got a Gold Medal for his trouble.  He remembered romping up Beggar’s Roost at maximum revs in bottom gear. 

By now the car had done about 25,000 miles and the cylinder bores were getting worn, so the engine was dismantled and completely overhauled, with new main and big end bearings, hardened liners to the bores and standard size Specialloid pistons. 

About this time Mac had several experimental cylinder heads made, and also tried out a number of proprietory aluminium heads, eventually fitting a Ricardo designed head with a compression ratio of 6.8 to 1.  This gave considerably more power, and on a test lap of Brooklands without screens or wings the car achieved a lap of 79 mph.  (of course the car was running un-supercharged at this point in its history and it is interesting as a side note to record we have now discovered that the aluminium heads are less effective than cast iron because they take too much heat away and give incomplete combustion.  One wonders how much more performance Mac would have achieved with the same designed head in cast iron!)  The car was so well streamlined that putting on the small aero screen and wings took 8 to 10 mph off the maximum speed. 

By the autumn of 1928 the body had got very tired (Mac describes it as “spent”) and the chassis was also a bit dicky, so the body was completely removed and the front axle, brakes and steering were overhauled, the body being scrapped.  He had, by then, become the proud owner of a “Hyper Sports” Supercharged Lea Francis 4 seater and was toying with the idea of making the Austin into a genuine sprint car.  After much cogitation a rough design was got out and, with the aid of one of the body shop carpenters, a new body frame was built and covered with Rexine fabric.  This made a very light construction.  At the same time the seating position was lowered, a new petrol tank fitted where the passenger seat used to be, and the radiator lowered and sloped back, the original bonnet being cut down to suit.  As a result of this the performance on hills and acceleration became really brisk and on getaway he could hold all but the fastest motorcycles. During the winter of 1928 the car went up to the Austin works for a series of bench tests with various cylinder heads, and the table below gives a summary of the results: 

The Ricardo head gave a flatter power curve with higher peak revolutions.  At that period the standard touring Austin Seven gave approximately 13 bhp at 2,800 rpm, and for the time the performance was good, as ordinary No 1 petrol was used for the tests, with a Solex carburetor having a 23 mm choke and 110 main jet. 

The first sprint Mac entered, with the car in its new guise, was at Lewes in March 1929 and the performance was good enough to get a first in the 1100 cc class with a time of 26.4 seconds.  The next event was a dirt-track race near Portsmouth, organized by the Portsmouth and Southsea Club – the field consisted of two Salmsons, an Amilcar, a Morgan and the Austin.  After a rather slow get getaway, due to wheel spin, a tremendous “dice” ensued, and on the last lap he managed to snatch the lead in a cloud of dust and cinders, to win by a length amid loud cheers.  Although very exciting Mac felt that this particular form of entertainment was very hard on the car and he never tried it again.  Later that year he ran in the October Brooklands Meeting and bagged a third in a Mountain race at 58.2 mph. 

In December 1929 Mac sailed for South Africa on business and so the Austin was put away until he returned home in June 1931.  By this time the blown “Ulster” Austin had appeared, and one of these was owned by his friend J. C. Elwes at Basingstoke.  Elwes had already done well at Brooklands, and together they were to race with their Austins and later with his J 4 MG and Aston Martins, in a good many events.  It was Elwes who fired Mac’s enthusiasm to make the “Tiddler” really fast, and they decided to convert the engine to the “Ulster” type.  Accordingly, an “Ulster” crankcase, crank, timing case, blower drive and No. 4 Cozette supercharger with Solex carburetor were obtained and the engine rebuilt, using an Alta aluminium cylinder head with a compression ratio of 6 to 1.  The bodywork was improved, heavier brake cables fitted, and the car had its first try out at Lewes in the spring of 1932, where it won the 1100 cc class with a time of 24.8 seconds.  Then came Shelsley Walsh and a tie for first place with E. R. Hall’s MG, the time being 49.2 seconds.  Mac mentions that when “Ulsterising” the engine, cast iron clutch linings, stronger clutch springs and a close ratio constant mesh gearbox pinions were fitted.  These raised first and second gears so that, with the 4.9 to 1 rear axle ratio, second was 7.07 to 1 and first 12.5 to 1.

The next event was the September Brooklands Meeting, and he gained first place in the Senior Mountain Handicap at 62.86 mph.  The Autocar magazine report said: “Maclachlan’s Austin traveled with such vim that it speedily took command of the situation, though it’s victory was as near as no matter snatched away by Shuttleworth’s Bugatti”.  This last-named car shot past him just as he crossed the finishing line and he had seen it out of the corner of his eye coming up the finishing straight very fast, and was in a fever of apprehension as to whether he would cross the line in time to win the race.     

During the 1933-34 seasons the Austin ran virtually unchanged, apart from a few detailed improvements, but increasing knowledge of the various courses enabled him to put up improved performances at most events.  The 1933 Whit Monday Meeting at Brooklands produced a second in the Mountain race at 63.8 mph, and the June Shelsley Walsh Meeting a first in the 850 cc racing car class in pouring rain, whilst the Brighton Speed Trials also gave a win in the 850 cc class, with J. C. Elwes driving.  The best performances in 1934 were 23.8 at Lewes and second in the 850 cc class at Brighton. 

By now Mac was really beginning to know his way up Shelsley Walsh and round the Mountain at Brooklands, and in May 1935 got up the former in 45.6 seconds, being third in the 850 cc class, whilst at the Whit Monday Brooklands Meeting he was second in a Mountain race at 67.5 mph; these were both great advances on previous best efforts.  However he felt that the limit had been reached with the existing boost of 9 lb/sq. in., so it was decided to make the car really potent.  His ambition was to get up Shelsley in under 45 seconds and Lewes in about 20 seconds, and possibly get round the Mountain at about 70 mph.  So during the summer the car was completely stripped and a design for the new layout drawn up.  In order to reduce the major alterations to the minimum possible the general idea was to make a genuine single-seater with a light streamlined body, with the driver seated over the rear of the propeller shaft and well back as this would throw the weight well back when accelerating and reduce wheel spin.A Centric 160 supercharger displacing 800 cc per revolution was driven off the front of the existing blower drive, which was fitted back to front in the timing case.  This gave about 17 lb/sq. in. boost and necessitated mounting the radiator rather far forward on an extension of the chassis frame.  A new induction system was built up out of steel tube, the clutch pedal moved to the near side, and a new remote gear change fitted.  The rear springs were mounted over instead of inside the chassis frame, lowering the rear of the car about 2½ inches, and a brand new “Ulster” dropped front axle assembly and spring was installed.  The castor angle was increased and the steering box mounted over the gearbox, with a long drag link.  The larger “Ulster” size brake drums and shoes were also fitted and an entirely new direct acting cable brake system, with heavier cables, made up.  New rear wheels with 17 inch by 4.25 tyres completed the chassis alterations. 

By this time Shelsley Walsh was looming up Mac decided to run the Austin as a chassis only to get some idea of what was going to happen.  A few preliminary runs to get ignition and carburetor settings about right showed that there was tremendous urge, and he set off full of hope.  The first practice run was very fast, but on the second, near the top of the hill, water started shooting out of the side of the engine and loud noises came from inside!  The head was taken off and disclosed that the gasket had gone, and more seriously one of the cylinder walls had collapsed and damaged a piston.  As Mac had been entered in the Austin Works Team something had to be done, so he rushed the car to Longbridge and worked all night fitting a new block, head and pistons: these were of the standard “Ulster” pattern.  They finally got through about 9.00 in the morning and went straight back to Shelsley very tired and dirty.  On the hill all went well and, in spite of feeling somewhat insecure, perched on the open chassis, he managed to put up a time of 45.4 seconds. 

It was obvious to Mac that he was “on to a good thing” but that the “Ulster” block and head were not going to be good enough for the high boost.  So Austins were approached and produced a new block, head and crankcase with extra holding down studs; the head had 25 studs of 3/8 in. diameter and was of aluminium, whilst the block had ten 3/8 in. studs holding it on to the crankcase.  The cylinder head gasket was made from 0.008 thou. thick copper foil.  When re-building the engine the opportunity was taken to put in a new 1½ journal “Ulster” crankshaft and con rods, also Austins produced some very beautiful slipper pistons with two 1/16 in. rings.  (we now believe these components to have come from the works “Rubber Duck” racer which had recently been brought up to the latest specification with a 32 stud cylinder head and block). 

The next stage in the development was the bodywork, and here Harrington’s of Hove, co-operated most successfully, making a lovely little single seater in aluminium on a framing of ½ in steel angle, a new fuel tank holding about 4½ gallons being fitted in the tail.  Initially it had a rather long nose, but this was subsequently shortened to give a great improvement.  (I believe Mac was a director of Harringtons at that time)   This work took place during the winter and by the spring of 1936 all was ready for arty out.  Several long runs with soft spark plugs, mudguards and a petrol-benzol mixture served to run-in the engine and a further series of full-power runs on a quiet stretch of road enabled the best ignition and carburetor settings to be arrived at.  (Imagine doing that today!).Unfortunately, some trouble with the fuel feed occurred at the Lewes Speed Trials in May, and the best time achieved was 22.4 seconds, the engine cutting out several times up the course.  However the performance showed that when properly going it should be able to get down to nearly the hoped-for 20 seconds.

At the next Lewes meeting all went well and the “Tiddler” made fastest time in the 1100 cc class and was third in the 1500 cc class, with times of 20.38 and 20.23 seconds; the latter time Mac was never able to improve upon.

After this came Shelsley Walsh with a time of 44.4 seconds on a showery day, when the hill was far from dry.  This was probably the Austin’s best performance as it was the fourth fastest time of the day, Raymond Mays’s ERA making FTD in 41.4 seconds.  Walter Baumer and Charles Goodacre made phenomenal climbs in 42.6 and 43.2 seconds respectively in the works Twin Cam Austins, but Mac had the satisfaction of beating Charlie Dodson in the other Works Austin and the redoubtable Hans Stuck in the Auto-Union.     

  The next event was the Poole Speed Trial in August 1936, and Mac rates this as one of his most enjoyable outings even though he had never previously competed there.  He records “Not only was the course most interesting but the organization was excellent and the day and surroundings lovely”.  There was quite a bit of “dicing” as the “S” bend near the finish was really most exciting, and Sydney Cummings von the Vauxhall Villiers finished up in the bushes after a terrific skid.  This was a most successful day for Mac, with wins in the 750 cc and 1100 cc classes and a third in the 1500 cc class.  The best time was 23.42 seconds which compared very favourably with an FTD of 22.82 seconds put up by George Hartwell in the ex E. R. Hall, Zoller supercharged MG Magnette.  At the last Lewes Meeting, after a tremendous tussle with Bert Hadley in the works side valve Austin Mac eventually emerged victorious by the narrow margin of 0.03 of a second with a time of “20.53 seconds.  On this occasion Waddy’s very clever four wheel drive two engined “Fuzzi” won the class with a time of 20 seconds dead. 

Above: B Leith

During the following winter the radiator, which as previously mentioned was too far forward, was cut down in size and set back above the front axle and supercharger.  The restyled bonnet greatly improved the look of the car.  The object was to reduce the weight on the front wheels and improve the handling by reducing the understeer.  At the same time new rear wheels with 16 inch by 5.25 in low pressure tyres were fitted, the previous 17 inch rear wheels being transferred to the front.  These large tyres enabled Mac to use a very low pressure of 15 psi at the front and 10 psi at the rear, which improved the cornering and grip and also made the car a lot more comfortable.  Mac records that it was very difficult to make the tail slide and there was remarkably little wheel spin when getting off the mark- the car appeared to shoot forward the moment the clutch was taken up. During 1937, 1938 and 1939 the only events in which the car ran were the Lewes and Brighton Speed Trials, as he found it impossible to get away to more distant meetings.  At nearly all these meetings Dennis Evans, in his very rapid “Montlhery” MG and the “Tiddler” had a tremendous series of ding-dong battles, first one then the other winning.  The outstanding duel and performance took place at Brighton in September 1937.   The Austin started off with 25.91 seconds, in the 850 cc class, Hadley taking 26.47 in the works Twin Cam racer and Evans 26.59.  In the 1100 cc class Hadley Broke the record with 25.7 seconds, Evans did 25.8 and Mac took 25.94 seconds.  In the 1500 cc class Mac got off to a really good start and broke the record with 25.56 seconds, which equates to 70.42 mph for the standing start half-mile, with Evans doing 26 dead and Hadley 26.02 seconds.  On the last run Mac crossed the finishing line at 6,400 rpm in top gear, which was just over 100 mph.  The last pre-war event in which the car ran was the Lewes Speed Trial in May 1939 and this gave another win in the 1100 cc class with a time of 21 seconds and a second place in the 1500 cc class with 20.5 seconds. 

After this catalogue of results Mac added some technical details about the car:The chassis is the original “Brooklands” model No 16476 and was registered YN 5058 on the 1^st March 1926.  The only modifications were the addition of the “Ulster” front axle, brakes and springs.  The rear springs were mounted on top of the chassis rail with additional clamps on the chassis extensions to increase the spring rate.    The gearbox was the original, with close ratio constant mesh gears, as was the rear axle, with the exception of the crown wheel and pinion.  This was the 4.9 to 1 “Chummy” ratio in place of the original 4.4 to 1 “Brooklands” ratio.  Mac also experimented with the 5.25 to 1 “Van” ratio but found the 4.9 to 1 ratio best as it gave better acceleration and 40 mph in first gear and 72 mph in second using 6,500 rpm.            The engine set up has already been described above and retained the original “Brooklands” high-lift camshaft.  The compression ratio was 5.8 to 1 and the maximum boost was about 17 lb/sq. in. The Centric supercharger is fed by a Solex 35 MOH, similar to those used on the un-supercharged Type 35 Bugattis.  The original BLIC magneto was retained and never missed a beat.  Latterly the Austin ran on Anglo M.G. /2 fuel   He used KLG  L.B. 1 spark plugs for warming up and road testing and long reach Champion N.A. plugs for competition.  The latter had a limited life but ensured that the car did not foul its plugs on the start line. As war approached the car was put into storage.  It had been, up to this time, one of the most successful sprint cars and regularly outclassed much heavier metal. 

 Post war Mac competed in a number of sprints at Dancers End, Luton Hoo and Brighton.In 1950 the car was sold to John Broad who was also campaigning an ERA.  He continued to win events during his ownership and then sold the car through Chiltern Cars who advertised it in Motor Sport in September 1953 for £265.  It was acquired by Ken Jack of Palace Gate Garage at about this time but there is no record of his having competed with it. 

Above: Luton Hoo Mac 1948	Above: Brighton, John Broad

From some time in 1957 I became acquainted with the Austin as I was a co-founder of the Surrey Sporting Motor Club and had just started racing my Austin 7 special.  One of our members was Jackie Epstein (son of the famous sculptor Jacob Epstein) who was working at the Palace Gate Garage in London and was responsible for maintaining the Austin.  He was having difficulty replacing the crankshaft which had broken and knowing that I had a suitable one pursued me to sell it.  At the time I was serving my apprenticeship with Vickers Armstrong at Brooklands and I recall having a telephone conversation with Jackie from a phone box in Byfleet outside the Hand and Spear pub where we used to go for lunch.  The gist of the conversation was “are you going to sell the parts for the Austin” to which my reply was “no”.  Jackie’s response was “well you’d better buy the car then” to which I said “OK” and we agreed a price of £150.

Now that was a lot of money when on a weekly wage of £4.50 and a good running Austin Seven could be bought for £12.  On returning to the pub to finish my lunch and tell my friends of my “deal” they all thought I had taken leave of my senses especially as I was not at all sure what I had agreed to buy.

As it happened I had the misfortune, the year before, to be run down by a passing motorist whilst pushing my Austin 65 to a garage on the Brighton road at Carshalton, having run out of petrol.  My left leg was very badly fractured and my own car ran me over as I fell.  The hospital were going to amputate the leg but my father insisted on getting a second opinion and a wonderful surgeon by the name of Stoker agreed to repair it with Monel metal plates and several long screws.  The operation was a complete success but I was off work for about 7 months.  Being only 20, and in those days a minor, my father acted on my behalf in claiming from the offending motorist’s insurance.  I finally received a payment of £600 which enabled me to buy the Austin and a brand new Morris Minor drophead. 

I collected the Austin, on a fixed tow bar, with the help of friends and began to research it’s history.  It was only at this stage that I realized what a historic car I had acquired.  The downside was that it needed a lot of work to make it raceworthy.  I investigated having a new crankshaft made by Laystall but the cost at £1000 was way outside my means and makes the current cost of a Phoenix crank and con rods look pretty good value.  The solution was to take a good Austin “Nippy” crankshaft to Tony Densham, who had recently set up in business as Sutton Rebore, and have it drilled to take pressure lubrication.  This crankshaft has never failed.  Another problem I found was the camshaft centre bearing in the crankcase which was designed to take the supercharged low lift camshaft which is similar to a standard one.  When Mac had fitted the “Brooklands” camshaft he had used the standard short rollers which had skewed on the centre bearing.  I was not happy with this and as the crankcase had also lost most of it’s front main bearing retaining lip I decided to have that repaired and at the same time line bore the camshaft centre bearing housing to take a late un-supercharged outer race.  This also made engine assembly much easier.

No chassis modifications were made but in those days most competition Austin Sevens were being fitted with Morris Minor brakes modified by Bowden Engineering of Ottery St. Mary in Devon and I decided to convert the “Mac”, as it became known, to this system.  Originally the pedals were arranged with a centre throttle and the brake pedal on the right.  I felt this was far too risky for a sprint car as I was used to the conventional layout, plus it was easier to fit the hydraulic brake master cylinder if the whole assembly was moved to the conventional position.  When I acquired the car it was fitted with the original 4.4 to 1 rear axle but the torque tube had fractured next to the banjo housing, it being the very early type, and so I had Stuart Rolt build up a 4.9 to 1 axle with the later and stronger casings.  These have scroll adjusters each side of the differential carrier and are much easier to set up than the earlier axles which have to be shimmed. 

I did very few meetings during the 1950’s and 1960’s with the Mac because I was a regular competitor in 750 Formula with my first Austin Special and then with the Marcos GT which is featured elsewhere in the Motormarques Archives.

John Miles and Stuart Rolt borrowed the Mac with the proviso that they built up their own engine which was a converted magneto unit.  This was rather un-successful as it was soon apparent that the power required to drive the supercharger was more than the standard cast iron timing gears could handle and they stripped as soon as the engine was revved up.  At this time I was working for Commer Cars (part of the Rootes Group) on truck chassis design and the gearbox section was below the design office.  So for 200 cigarettes the production line was programmed to make two sets of special timing gears for the Austin.  As there is no requirement for a dynamo the gears came out with 27½ degrees helix angle (the same as a Commer gearbox!) which gave a much stronger tooth form.  They were heat treated on the teeth with soft centres so that they would bed firmly onto the camshaft taper.  These new gears have continued to give excellent service. 

In the late 1980’s I decided it was time to get to grips with the Mac and so a major overhaul and refurbishment was undertaken.  The engine was fitted with a new Phoenix crankshaft and con rods, the oil feed was redesigned using a front nosepiece in aluminium using the original as a pattern.  The Morris Minor brakes had become rather a liability as the slave cylinders would seize up if not used regularly and a decision was made to revert to cable brakes.  In order improve on the standard arrangement Austin semi-Girling brakes were fitted but modified to make the shoes fully floating.  At the same time a front to rear compensating mechanism was built which has a chain running over two sprockets on the cross shaft (similar to that on a Bugatti).  This enabled the brake levers to be of different lengths front and rear so that it now has about 70% braking on the front.  A further advantage of this modification is that all the “lost motion” in the system is eliminated and the brakes have a very firm pedal and are now as good as any hydraulic system. 

The car now runs on a fuel mixture we call 80-10-10 which consists of 80% Methanol, 10% Benzine or Toluene and 10% 100 octane petrol.  Spark plugs are NGK 8 and it will start and run on these and idle quite happily.  I tried 100% Methanol with a much lager main jet but it would not idle.   The Centric supercharger was also redesigned as I was concerned that using high engine revs could cause the vanes to touch the outer casing which would be catastrophic.  New interlocking blade carriers were designed and cast and the central shaft diameter was increased in diameter.  The supercharger drive was remade using a Simms CR diesel pump drive in place of the original Austin 12/4 dynamo coupling. 

I was now getting a very good performance and took a number of class awards at Prescott and Shelsley Walsh hill climbs.  In 1999 I was at the Etretat meeting in France and made a very fast first run which gave me a class win but on the second run the engine started to blow back into the supercharger.  Returning to the UK the cylinder head was removed and I found there was trail of rust from number 8 valve running down the bore.  I assumed, wrongly it transpired, that the head gasket was the cause.  The block was removed and taken to Paul Bonewell, an acknowledged expert, for further investigation.  Two days late he called me to say that, having filled the water jacket with WD 40, the block was cracked all around the bottom of the cylinder wall where the water jacket starts.  This was a serious blow as these works 10 stud blocks with 25 studs at the top are unobtainable.   From historical research it would seem that the failure of the cylinder blocks at this point was an old problem which Austins never discovered as it was not at all obvious.  Why else would they have gone on increasing the number of cylinder head studs to 32 when the normal 14 should have been quite adequate on such a small engine. 

Fortunately a very good friend of mine, who has become very active in the Austin Seven world, had patterns made to cast new cylinder blocks to the original specification but with additional metal at the weak points.  I was very happy when he agreed to allow me to have one of the first castings which came from Harlings Foundry in Hastings.  Paul Bonewell machined it and has been a great success without which the car would be static. At about this time there was a project to reproduce replicas of the works slipper pistons mentioned by Mac.  These were made by David Fletcher-Jones, who is a piston expert, so that they would accommodate metric sized rings and also be available in various sizes to allow for overboring the cylinders when they become worn.  He also made some very nice new cast iron clutch linings.  These are essential on the higher output racers as they take the heat away from clutch centre plate and also give a much smoother operation. 

After completing all this work it was disappointing to continue to suffer from blow back in the supercharger and it took quite some time to work out what was wrong.  Eventually it was traced to a magneto problem which I had never encountered before.  Although the magneto had been rebuilt and tested by Tony Stairs (who else!) it developed a strange fault which only occurred after a couple of runs.  The brush which runs around the inside of the distributor cap had started to deposit carbon which caused the ignition firing to become random.  This fault has yet to be explained but maybe after 80 years it just got tired!  Another BLIC magneto has now been rebuilt and fitted but this has the rotor arm type distributor more akin to a modern system and works perfectly.  One thing is for certain; in Motor Racing one never stops learning.  Whilst all this was being investigated and resolved I had a re-think about the engine performance and came to the conclusion that the original “Brooklands” camshaft whilst providing plenty of power low down was not allowing the engine to rev above 6,500 rpm without valve bounce.  There was evidence of this in the cylinder head combustion chambers which had always been a mystery to me in spite of the massive valve springs.  I therefore decided, in consultation with Paul Bonewell, to take an old “Nippy” camshaft from my box of spares and re-profile it with a more progressive profile and very much lighter tappet blocks.  The result of this is the ability to run up to 8,500 rpm which increases the power output to somewhere near 85 bhp!  With the car weighing only 6 cwt this gives a power to weight ratio of over 300 bhp/ton. Problem:  The Vintage Sports Car Club in their wisdom have decreed that in order to run as Vintage (pre 1931) the wheel size must not be less than 16 inches.  Next problem: Nobody makes a racing tyre anywhere near small enough in 16 inched diameter.Currently I am experimenting with all manner of different wheel and tyre combinations, even trying twin rears with soft 17 inch road tyres.   All this is expensive and time consuming and I may yet have to consider a change of axle ratio.  Even after all this I still get a thrill from owning and competing in this fantastic, historic, little car which continues to amaze with its performance and looks.  Here’s to more fun and games in 2007 when I will have owned the Mac for 50 years!  

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