FOUR LITRE BENTLEY ARTICLES
THIS ARTICLE WAS FIRST PUBLISHED IN THE BDC REVIEW
THE 4 LITRE ENGINE STORY part 1 By Alan C Smith
INTRODUCTION
There is very little of the Bentley story that has not been told over and over again. One area that hasn`t really been extensively explored is the 4 Litre, especially the engine.
The mere mention of the 4 Litre is enough to make the top lip of the hardened Bentleyphile curl. We read and hear it`s not a ” real ” Bentley. Wally Saunders is quoted as saying ”We all said at the time it smelt, that 4 Litre. It seemed very funny to us that certain of the high-ups insisted on that shocking thing over WO`s head. There was one man in particular who`d come in from another firm; he had a lot to do with the 4 Litre. It sort of stank to us, almost as if he was there to break the company. And it did, that 4 Litre did help to break up the company. Most of the remaining money went on that awful car, and they must have known from the start it would be no good, must have. I mean, what else could we think?” An obvious reference here to Barrington. WO puts the boot in, with his comment ” What we did instead was to design and market a new car, the 4 Litre of unhappy memory” Many believe that WO had nothing to do with the 4 Litre design and WO himself, in his writings, can be seen to shy away from his involvement in the project, although he does leave some clues about this.
Is the vitriol thrown at the 4 Litre justified? Was it as bad as everybody says? According to Hassan, the 4 Litre ”Was a very good engine.” Who can we believe?
This is the first of several proposed articles in which I will attempt to explore the myths
surrounding the gestation, life and the ultimate demise of the 4 litre engine.
Unfortunately the people we need to question about the 4 litre are no longer with us. And even if they were, could we rely on possibly sanitised memories stretching back 70 years.
One of the problems encountered by the researcher looking into the written word is that a biography, due to the compression of a whole life into a book, can contain inaccuracies or omissions A typical example is WO`s autobiography, when closely examined, we can see that the chronology of the events around the 4 Litre era is unreliable. Another reason for distortions, could be due to the subject wanting to put a better face on past events.
I will have to make some assumptions, based on deductions from the collected facts, from various sources ( some new ). And hope the readers with better knowledge will respond to put the record straight if necessary. It is not my intention to create or distort history, merely to try to find out what really happened in those dark days before the demise of the company. To this end I am also drawing on my own experience as a design engineer in automobile and other industries. For over 40 years I have witnessed many such Board Room wrangles and office political intrigues such as we will see happened at Bentley Motors. As in any investigation delving into the past, the process of finding answers to questions will inevitably result in the creation of yet more questions that need to be answered.
THE MAIN CHARACTERS
Firstly let me assemble, and try to put life into the principal characters in this real life drama. The following mini biographies will help the reader who may not be so familiar with Bentley history.
WO BENTLEY
His life is well documented, but what kind of a person was WO ?
Born in 1888 he came from a privileged background.At school he had the courage to fly to the help of others being bullied, fists flying. His skill in engineering developed early, and his apprenticeship at GNR in Doncaster taught him discipline and duty. Tuning the engines for his motor cycles,and later the DFP cars, gave him valuable insight into engineering problems allied to performance, and his discovery of the aluminium piston was the key to his future.
In 1915 he contacted the War Department and offered his secret. The result was, that without any formal qualifications, solely due to his discovery of the Aluminium piston backed up by the DFP racing results, he was invited to join the RNAS. And went on to design his own version of the Clerget rotary engine in which he was able to iron out the reliability problems that had plagued the French designed engine. This engine became the famous BR1. He then went on to design a more powerful version designated the BR2. Which gave the allies air supremacy in 1918
WO has been described as a genius for this feat, and when one considers his limited experience at that time, it was a brilliant achievement. This gave him the confidence to design and manufacture his own car in collaboration with Burgess and Varley.
Although Bentley motors never really belonged to him , WO was autocratic where engineering decisions were to be made, and did not respond well to being told to do things, which he considered wrong, by non engineer board members. He was painfully shy, which he hid behind an aloof manner, but could be stubborn and abrasive when pushed.
HARRY RALPH RICARDO
Also from a privileged background, Ricardo was born in 1885 not more than 2 miles from where WO was to be born three years later. Educated at Rugby where he designed and built a steam engine, he attended lectures at The Royal Institution given by Sir Dugald Clerk, then regarded as the highest British authority on internal combustion engines. Clerk`s theories on the principles of stratified charge stimulated Ricardo to design and build his first internal combustion engine at the age of 17.
Further educated at Cambridge University where the experience of designing and building his own 900 cc motor cycle turned his career away from civil engineering to mechanical engineering. After Cambridge whilst holding down a day job at Rendel & Robertson the family firm ,around 1906 Ricardo designed the dolphin 2 stroke marine engine, which modified, later propelled the Dolphin car exhibited at Olympia in 1908.
This was not a success, but Ricardo redesigned the engine for a cyclecar called the Vox produced from 1911 to 1914.
In 1914, now a partner in Rendel & Robertson, Ricardo was sent to the USA to visit various engineering companies and later to Europe where, whilst in Germany visiting Professor Hugo Junkers,he was advised to leave the country just 2 days before war broke out.
In 1915 frustrated by having no purpose ( Just as WO was), whiling away the time finishing off a 300 hp aero engine design, he met Lieutenant T B Barrington a volunteer engineering officer in the RNAS.
Ricardo was engaged by the RNAS to design a 600 hp engine for a single engined biplane submarine killer. This unlikely project was shelved, and Ricardo went on to design the engine for the MK 5 Tanks. The specification of the engine called for a max power of 150 hp and no aluminium or high tensile steel were to be used in it`s construction. Interestingly, the epicyclic transmission was designed by Wilson.
After the armistice, the subtantial royalties earned from the tank engine, enabled Ricardo to build his premises ”Bridge Works” at Shoreham. Completed in 1919, this enabled Ricardo to carry out his important work on fuels.
In 1917 Ricardo developed and patented ”The Turbulent Head” for side valve engines. Later used by car manufacturers around the world.
Ricardo wrote his book ”The Internal Cumbustion Engine” Published in 1923 – 1924. later rewritten as ”The High Speed Internal Combustion Engine” which remained in print through many editions for almost fifty years.
Around 1927, jointly with the French company S.I.C.,Ricardo patented ”The High Power Head”. Based on ”The Turbulent Head” but with overhead inlet valves.
This brings us up to the period we will be looking at.
What about Ricardo himself? There are few clues to his personality, apparently he spoke with a slight stammer, and in common with WO, was shy and retiring.
To this day Ricardo Consulting Engineers Ltd. are still at the forefront of engine technology.
COLONEL THOMAS BARWELL BARRINGTON
We do not have a lot of information about Barrington. Perhaps one of our readers can throw some more light on his life. Barrington had served his apprenticeship at Rolls Royce and the first we really know about him is that in 1915 he was serving as a Lieutenant in the RNAS as second in command to Commander Briggs.
After the War he returned to Rolls Royce at Derby as Assistant Chief Engineer and in 1920 renewed his association with Ricardo by engaging his help in the design of pistons for the 40/50 & Condor engines.
It is obvious that they were friends and kept in contact, and after Barrington had left Rolls Royce in the mid 1920`s, they again collaborated in 1927, when Barrington was working for Sheffield Simplex.
The next we know is that Barrington commenced a three year contract with Bentley Motors dating from 1 st November 1929.The question is, who headhunted Barrington for Bentley Motors? More of this later.
THE CONNECTIONS
Now that we have assembled the main characters, let us look at the time they first interacted. The date 1915,the place London and the catalyst Commander Wilfred Briggs of the Royal Naval Air Service.
The RNAS, established in 1914, was part fighting force and part research organisation responsible for the air defence of Great Britain in addition to its coastal defence. The RNAS was merged with the RFC to become the Royal Air Force in 1918.
Briggs was the commanding officer of a section dedicated to Aero engine design and procurement. It was the same Briggs who, at the outbreak of war, requisitioned the Mercedes Benz Grand Prix racing car then on display the Mercedes London showroom. The car was transported to Rolls Royce at Derby where eventually WO was able to examine it`s dismantled engine and later incorporated some of the design features into the three litre engine.
Leiutenant T B Barrington was Brigg`s second in command. In Ricardo`s opinion Briggs was a go-getter and an optimist who lacked technical knowledge and relied on Barrington for engineering expertise. WO gives a glowing account of Briggs in his autobiography. It seems that Briggs was very skilled in getting the best out of people and organisations.
Ricardo worked on the design of the engine for the”flying destroyer”which was later dropped. WO went to Gwynnes at Chiswick to help with the Clerget rotary engine which they made under licence. We do not know if WO and Ricardo knew each other at this time. They Certainly met at the 1922 TT race and kept in touch thereafter.
At the 1922 TT race Vauxhall fielded a team of three cars fitted with a Ricardo designed 3 Litre 4 cyl. Engine of advanced design. Incorporating double overhead camshafts and four valves per cylinder with an output of 129 hp at 4500 rpm. One of these cars took third place beating WO in the Bentley by six seconds.
Now did WO and Barrington know each other? Barrington as Briggs`s second in command would have been around when WO visited Briggs. Also, as Briggs had no Technical knowledge, Barrington would have appraised WO`s ideas and design drawings to give an opinion about them to Briggs.
BIRTH OF THE 4 LITRE ENGINE
WO states in his autobiography ”For several years the volume of cheap, mass-produced cars had been growing, and there were fewer and fewer people prepared to pay the vastly higher prices for a hand built vehicle”.
The problem with the Bentley engines, which were all based on the original three litre engine, was that they were becoming outdated and gave a poor performance in terms of bhp/litre and bhp/lb of engine weight compared to more modern designs. A radical approach to address this problem would have to be taken.
The board at Bentley motors could see the trend and therefore approved a programme to design a smaller, cheaper, more efficient and quieter engine to power a smaller non sporting town carriage. In fact, a potential competitor to the Rolls Royce 20 / 25. This probably would have been a one man low priority design project given the existing activity in the drawing office around 1927.
As this was basically an experimental engine we can imagine that WO, although disapproving of the side valve specification, would have gone along with the board of directors as it was not affecting his current projects. He probably hoped that the 4 Litre project would just die and fade away.
The actual starting date for the design is not known exactly. Harry Weslake intimates that Bentley Motors were working on an unsuccessful single cylinder side valve engine in 1927/28. This produced 11 bhp from 600cc, which meant an output of 66 hp from a six cylinder engine of 3.6 litres. A very poor result for this capacity, probably much to the satisfaction of WO, who could then advise the board that the engine needed overhead valves.
The fact that they were experimenting with a single cylinder engine meant that the preliminary design of the whole engine had already been laid out. We do know that the detail drawings for the engine were being drawn up in early 1929 under Burgess`s supervision.
Wally Hassan in his book states that three separate heads were tried, from the designs of Weslake, Whatmaugh and latterly Ricardo.
In 1929, with the recession in America starting to bite, the programme for the four litre would have become accelerated. The problem was, that the engine in its present advanced state was not viable, Burgess was sick, and WO was not able to or would not design the cylinder head, which in his opinion was a retrograde step for Bentley Motors.
WO in his autobiography states ”I declined as politely as I could to have anything to do with the top half, I don`t know anything about pushrods, I`m afraid, I said. I think you`d better get someone else to look after this cylinder head”. The implication here, is that because of the poor results given by the Weslake and Whatmough cylinder heads for the 4 Litre side valve version, the board had approved the use of pushrod actuated overhead valve gear for the cylinder head to improve the power output.
It`s difficult to comprehend why WO would refuse this task, as the design of the pushrod OHV should have been relatively simple for him, and certainly more in line with what he considered to be right. What were his reasons? Had he lost confidence? Remembering that WO was a conceptual designer and had relied upon Burgess, since the beginning, to produce the main design and detail work, as he had relied on Petty Officer Aslin in the RNAS. Now Burgess was sick and unable to help him, had WO lost it? Or was he just being stubborn, refusing to carry out work which he considered to be inappropriate. Whatever the reason, the other board members must have been very concerned by WO`s attitude, as this was a direct refusal to carry out their instructions. Under normal circumstances this would be grounds for dismissal , and there was nobody else to step in to carry on the conceptual design. Given the urgency of the project this was commercial suicide!
We can speculate that this was the moment that Barnato has hinted at, when the board actually considered letting WO go. Feelings must have been running very high at that time, but it`s difficult to see how they really could dismiss WO without damaging the company in the process.
Now we come to the appointment of Barrington as chief designer.
On the 24 th of August 1929 Ricardo received a letter from WO enquiring if Ricardo might be interested in entering into a consulting agreement with Bentley Motors. With the aim of jointly designing and developing an entirely new engine capable of producing a higher specific output in terms of horsepower per litre and pound of weight than had been possible in previous Bentley engines.
WO received a reply to the affirmative on the 2 nd of september. Later in September WO visited Ricardo at his premises at Bridge Works in Shoreham. We can speculate, that whilst discussing the details of the High Power Head which had already been fitted to a Chenard et Walcker with excellent results by CIS the joint patent holders, who owned the marque. WO mentioned that he was looking for a chief designer, as Burgess was terminally ill and unable to work. Perhaps Ricardo suggested Barrington as a possible replacement, as they were friends, and Barrington had probably mentioned to Ricardo that he was looking for a change of employers. And of course, as we have seen, WO knew him.
The timing is plausible, as there would have been just enough time from the middle of September to the 1 st of November, When Barrington started at Bentley motors, for the appointment to be aproved by the board of directors, the contract of employment to be negotiated, and Barrington to tender a month`s notice to his employer.
Bentley Motors waited until after Burgess`s death, announcing Barrington`s appointment on the 7 th of December, understandably out of respect to Burgess, who passed away on the 30 th of November.
Ricardo duly had some proposal sketches for the cylinder head prepared and sent to Bentley Motors, where under the supervision of Barrington, the production design drawings were prepared.
Again we can speculate that WO had boxed himself into a corner this time, as it is highly probable, that after the problems the board had with him, they chose to bypass WO, and communicate directly with Barrington about the design of 4 Litre. A cylinder head was made to suit the single cylinder test engine which was used to check the viability of the design before committing resources to the finished version.
There is still in existence a copy of the single cylinder power curve dated 31 st January 1930. the maximum power obtained was 22 bhp @ 4050 rpm. Multiply this by six and we arrive at a figure of 132 bhp, only 15 bhp short of a standard 6 ½ engine.The board must have been jubilant, what a result, with the possibility of even higher output yet to come. Poor WO would have been discredited and completely marginalised now.
This has been leading up to a question about why WO never mentions Barrington in any of his books? Possibly WO thought that Barrington had contributed to his and the company`s problems, and very likely they did not actually get on. This is not surprising given WO`s realisation that he had unwittingly relinquished his function in the company to Barrington, and no longer had any real say in design. Some sources say that they did not know each other. This is not credible as the Drawing Office was on the floor above WO`s office, they must have had some contact, assuming that WO still had some official areas of influence. Also at board meetings, WO would have been present, and probably posed technical questions when Barrington presented his progress reports. WO certainly would have had access to the engineering drawings, and as often happens, probably kept a discreet eye on things by going round looking at the designs on the drawing boards during the evenings and week ends, after the staff had gone. Frank Ayto the Chief Draughtsman would have kept him well informed of any happenings in the drawing office.
PRELIMINARY CONCLUSIONS
What conclusion can we draw from the above first episode?
The power output claimed by Bentley Motors for the 4 Litre engine was 120 hp at 4000 rpm. Comparing this with the power output promised by the single cylinder engine, obtained by multiplying the output of 22 hp by six, giving a total output of 132 hp at 4050 rpm, there is a discrepancy of 12 hp. So what happened to the missing horsepower?
The Ricardo design although potentially very efficient, was very new, and only the Chenard Walcker engine had been fitted with the high power head previous to its application to the 4 Litre.
With hindsight, Bentley motors should have used proven technology given the prevailing time and cost restraints. The reason the 4 Litre engine was not able to be developed to give the output promised by the single cylinder engine, was because the initial Ricardo design gave no latitude for change or tuneability, this would require a redesign of the block and cylinder head, but of course it was too late for this, Bentley Motors went into liquidation.
If WO had done as the board requested, and designed a push rod overhead valve cylinder head with four valves per cylinder, and spark plugs located at the top of the combustion chamber. The 4 Litre engine would have arguably then produced more power than with the Ricardo high power head, which is basically just a compromise between side and overhead valve layouts in terms of cost and performance. Also, very importantly, the OHV head would have been capable of further tuning and development.
We could take the view that Ricardo must shoulder most of the blame for the failure of the 4 Litre engine, as the design of the cylinder head was critical to performance, and was translated directly into design drawings by Bentley Motors drawing office from Ricardo`s design sketches. Basically, Bentley motors were doing the development work for Ricardo, on a design that was not yet fully proven. If the Chenard Walcker engine was so sucessful, why wasn`t this reflected in the 4 Litre? Ricardo`s engineers would have been in contact with Barrington, and as normal with a consultancy agreement, would have received the main layout drawings from Bentley Motors for their perusal. And would have duly reported back to Barrington, if in their opinion, there was anything untoward with the design .
Perhaps we should also blame WO for refusing to countenance the pushrod OHV, and agreeing to incorporate the Ricardo head. It is most probable that he was the one that recommended this course of action to the board, as there is no doubt WO had the start up meeting with Ricardo. This was a crucial and wrong decision which ultimately flawed the final result. As we know, there was only one chance to get it right, and they didn`t.
In the next episode I will reveal what I found in Ricardo`s Files when i visited their works at Shoreham. Also we will look at the design of the 4 Litre engine itself and try to resolve some anomalies.
Anybody owning a 4 Litre engine or who has experience of the engine or just interested please read my letter in ”Letters to the Editor.”
Below is a copy of the letter that I sent to the BDC Review editor at the same time as the article
Dear Richard,
Unfortunately the members who own 4 Litre Bentleys have the least technical support of any other model in the Bentley range. In the Technical Facts, only five pages are dedicated to the 4 Litre, and as far as I know, there are no other sources of information available. This is a situation which must be adressed.
I would like to contact anyone owning a 4 Litre engine. Who has owned a 4 Litre engine and has some experiences or knowlege to impart. Anyone that has any engine spares which could be used as patterns where drawings do not exist. Any Restorers or private individuals who have restored a 4 Litre engine. Anyone who has, or is making parts for the engine. In fact any information at all that will help 4 Litre owners in the future, to source parts and rebuild their engines.
I am prepared to collate any information supplied and make it available to all the interested parties, including the club, so it can be included in the Technical Facts.
It would be very interesting to know how many engines survive, so would all engine owners please please contact me with their engine numbers. These can be found on the front of the crankcase near the top of the timing case where the front cover joins it. Please also quote the crankcase part number. This will be found on the left hand side of the engine to the rear of the water pump stamped onto a square raised boss.
If there is enough interest it would be possible to form a little support group within the club as is done in the VSCC. Perhaps with an occasional newsletter.
Richard Evans has given me some information about problems with No. 5 big end, has any body else experienced this? I have in my posession a sump oil tray which has a repaired hole in it at the No. 5 rod position.
Dan Rens, the 4 Litre racer, is just finishing his engine rebuild and hopefully the car will reappear soon.
Yours Faithfully,
CLICK HERE FOR PART TWO
INTRODUCTION
There is very little of the Bentley story that has not been told over and over again. One area that hasn`t really been extensively explored is the 4 Litre, especially the engine.
The mere mention of the 4 Litre is enough to make the top lip of the hardened Bentleyphile curl. We read and hear it`s not a ” real ” Bentley. Wally Saunders is quoted as saying ”We all said at the time it smelt, that 4 Litre. It seemed very funny to us that certain of the high-ups insisted on that shocking thing over WO`s head. There was one man in particular who`d come in from another firm; he had a lot to do with the 4 Litre. It sort of stank to us, almost as if he was there to break the company. And it did, that 4 Litre did help to break up the company. Most of the remaining money went on that awful car, and they must have known from the start it would be no good, must have. I mean, what else could we think?” An obvious reference here to Barrington. WO puts the boot in, with his comment ” What we did instead was to design and market a new car, the 4 Litre of unhappy memory” Many believe that WO had nothing to do with the 4 Litre design and WO himself, in his writings, can be seen to shy away from his involvement in the project, although he does leave some clues about this.
Is the vitriol thrown at the 4 Litre justified? Was it as bad as everybody says? According to Hassan, the 4 Litre ”Was a very good engine.” Who can we believe?
This is the first of several proposed articles in which I will attempt to explore the myths
surrounding the gestation, life and the ultimate demise of the 4 litre engine.
Unfortunately the people we need to question about the 4 litre are no longer with us. And even if they were, could we rely on possibly sanitised memories stretching back 70 years.
One of the problems encountered by the researcher looking into the written word is that a biography, due to the compression of a whole life into a book, can contain inaccuracies or omissions A typical example is WO`s autobiography, when closely examined, we can see that the chronology of the events around the 4 Litre era is unreliable. Another reason for distortions, could be due to the subject wanting to put a better face on past events.
I will have to make some assumptions, based on deductions from the collected facts, from various sources ( some new ). And hope the readers with better knowledge will respond to put the record straight if necessary. It is not my intention to create or distort history, merely to try to find out what really happened in those dark days before the demise of the company. To this end I am also drawing on my own experience as a design engineer in automobile and other industries. For over 40 years I have witnessed many such Board Room wrangles and office political intrigues such as we will see happened at Bentley Motors. As in any investigation delving into the past, the process of finding answers to questions will inevitably result in the creation of yet more questions that need to be answered.
THE MAIN CHARACTERS
Firstly let me assemble, and try to put life into the principal characters in this real life drama. The following mini biographies will help the reader who may not be so familiar with Bentley history.
WO BENTLEY
His life is well documented, but what kind of a person was WO ?
Born in 1888 he came from a privileged background.At school he had the courage to fly to the help of others being bullied, fists flying. His skill in engineering developed early, and his apprenticeship at GNR in Doncaster taught him discipline and duty. Tuning the engines for his motor cycles,and later the DFP cars, gave him valuable insight into engineering problems allied to performance, and his discovery of the aluminium piston was the key to his future.
In 1915 he contacted the War Department and offered his secret. The result was, that without any formal qualifications, solely due to his discovery of the Aluminium piston backed up by the DFP racing results, he was invited to join the RNAS. And went on to design his own version of the Clerget rotary engine in which he was able to iron out the reliability problems that had plagued the French designed engine. This engine became the famous BR1. He then went on to design a more powerful version designated the BR2. Which gave the allies air supremacy in 1918
WO has been described as a genius for this feat, and when one considers his limited experience at that time, it was a brilliant achievement. This gave him the confidence to design and manufacture his own car in collaboration with Burgess and Varley.
Although Bentley motors never really belonged to him , WO was autocratic where engineering decisions were to be made, and did not respond well to being told to do things, which he considered wrong, by non engineer board members. He was painfully shy, which he hid behind an aloof manner, but could be stubborn and abrasive when pushed.
HARRY RALPH RICARDO
Also from a privileged background, Ricardo was born in 1885 not more than 2 miles from where WO was to be born three years later. Educated at Rugby where he designed and built a steam engine, he attended lectures at The Royal Institution given by Sir Dugald Clerk, then regarded as the highest British authority on internal combustion engines. Clerk`s theories on the principles of stratified charge stimulated Ricardo to design and build his first internal combustion engine at the age of 17.
Further educated at Cambridge University where the experience of designing and building his own 900 cc motor cycle turned his career away from civil engineering to mechanical engineering. After Cambridge whilst holding down a day job at Rendel & Robertson the family firm ,around 1906 Ricardo designed the dolphin 2 stroke marine engine, which modified, later propelled the Dolphin car exhibited at Olympia in 1908.
This was not a success, but Ricardo redesigned the engine for a cyclecar called the Vox produced from 1911 to 1914.
In 1914, now a partner in Rendel & Robertson, Ricardo was sent to the USA to visit various engineering companies and later to Europe where, whilst in Germany visiting Professor Hugo Junkers,he was advised to leave the country just 2 days before war broke out.
In 1915 frustrated by having no purpose ( Just as WO was), whiling away the time finishing off a 300 hp aero engine design, he met Lieutenant T B Barrington a volunteer engineering officer in the RNAS.
Ricardo was engaged by the RNAS to design a 600 hp engine for a single engined biplane submarine killer. This unlikely project was shelved, and Ricardo went on to design the engine for the MK 5 Tanks. The specification of the engine called for a max power of 150 hp and no aluminium or high tensile steel were to be used in it`s construction. Interestingly, the epicyclic transmission was designed by Wilson.
After the armistice, the subtantial royalties earned from the tank engine, enabled Ricardo to build his premises ”Bridge Works” at Shoreham. Completed in 1919, this enabled Ricardo to carry out his important work on fuels.
In 1917 Ricardo developed and patented ”The Turbulent Head” for side valve engines. Later used by car manufacturers around the world.
Ricardo wrote his book ”The Internal Cumbustion Engine” Published in 1923 – 1924. later rewritten as ”The High Speed Internal Combustion Engine” which remained in print through many editions for almost fifty years.
Around 1927, jointly with the French company S.I.C.,Ricardo patented ”The High Power Head”. Based on ”The Turbulent Head” but with overhead inlet valves.
This brings us up to the period we will be looking at.
What about Ricardo himself? There are few clues to his personality, apparently he spoke with a slight stammer, and in common with WO, was shy and retiring.
To this day Ricardo Consulting Engineers Ltd. are still at the forefront of engine technology.
COLONEL THOMAS BARWELL BARRINGTON
We do not have a lot of information about Barrington. Perhaps one of our readers can throw some more light on his life. Barrington had served his apprenticeship at Rolls Royce and the first we really know about him is that in 1915 he was serving as a Lieutenant in the RNAS as second in command to Commander Briggs.
After the War he returned to Rolls Royce at Derby as Assistant Chief Engineer and in 1920 renewed his association with Ricardo by engaging his help in the design of pistons for the 40/50 & Condor engines.
It is obvious that they were friends and kept in contact, and after Barrington had left Rolls Royce in the mid 1920`s, they again collaborated in 1927, when Barrington was working for Sheffield Simplex.
The next we know is that Barrington commenced a three year contract with Bentley Motors dating from 1 st November 1929.The question is, who headhunted Barrington for Bentley Motors? More of this later.
THE CONNECTIONS
Now that we have assembled the main characters, let us look at the time they first interacted. The date 1915,the place London and the catalyst Commander Wilfred Briggs of the Royal Naval Air Service.
The RNAS, established in 1914, was part fighting force and part research organisation responsible for the air defence of Great Britain in addition to its coastal defence. The RNAS was merged with the RFC to become the Royal Air Force in 1918.
Briggs was the commanding officer of a section dedicated to Aero engine design and procurement. It was the same Briggs who, at the outbreak of war, requisitioned the Mercedes Benz Grand Prix racing car then on display the Mercedes London showroom. The car was transported to Rolls Royce at Derby where eventually WO was able to examine it`s dismantled engine and later incorporated some of the design features into the three litre engine.
Leiutenant T B Barrington was Brigg`s second in command. In Ricardo`s opinion Briggs was a go-getter and an optimist who lacked technical knowledge and relied on Barrington for engineering expertise. WO gives a glowing account of Briggs in his autobiography. It seems that Briggs was very skilled in getting the best out of people and organisations.
Ricardo worked on the design of the engine for the”flying destroyer”which was later dropped. WO went to Gwynnes at Chiswick to help with the Clerget rotary engine which they made under licence. We do not know if WO and Ricardo knew each other at this time. They Certainly met at the 1922 TT race and kept in touch thereafter.
At the 1922 TT race Vauxhall fielded a team of three cars fitted with a Ricardo designed 3 Litre 4 cyl. Engine of advanced design. Incorporating double overhead camshafts and four valves per cylinder with an output of 129 hp at 4500 rpm. One of these cars took third place beating WO in the Bentley by six seconds.
Now did WO and Barrington know each other? Barrington as Briggs`s second in command would have been around when WO visited Briggs. Also, as Briggs had no Technical knowledge, Barrington would have appraised WO`s ideas and design drawings to give an opinion about them to Briggs.
BIRTH OF THE 4 LITRE ENGINE
WO states in his autobiography ”For several years the volume of cheap, mass-produced cars had been growing, and there were fewer and fewer people prepared to pay the vastly higher prices for a hand built vehicle”.
The problem with the Bentley engines, which were all based on the original three litre engine, was that they were becoming outdated and gave a poor performance in terms of bhp/litre and bhp/lb of engine weight compared to more modern designs. A radical approach to address this problem would have to be taken.
The board at Bentley motors could see the trend and therefore approved a programme to design a smaller, cheaper, more efficient and quieter engine to power a smaller non sporting town carriage. In fact, a potential competitor to the Rolls Royce 20 / 25. This probably would have been a one man low priority design project given the existing activity in the drawing office around 1927.
As this was basically an experimental engine we can imagine that WO, although disapproving of the side valve specification, would have gone along with the board of directors as it was not affecting his current projects. He probably hoped that the 4 Litre project would just die and fade away.
The actual starting date for the design is not known exactly. Harry Weslake intimates that Bentley Motors were working on an unsuccessful single cylinder side valve engine in 1927/28. This produced 11 bhp from 600cc, which meant an output of 66 hp from a six cylinder engine of 3.6 litres. A very poor result for this capacity, probably much to the satisfaction of WO, who could then advise the board that the engine needed overhead valves.
The fact that they were experimenting with a single cylinder engine meant that the preliminary design of the whole engine had already been laid out. We do know that the detail drawings for the engine were being drawn up in early 1929 under Burgess`s supervision.
Wally Hassan in his book states that three separate heads were tried, from the designs of Weslake, Whatmaugh and latterly Ricardo.
In 1929, with the recession in America starting to bite, the programme for the four litre would have become accelerated. The problem was, that the engine in its present advanced state was not viable, Burgess was sick, and WO was not able to or would not design the cylinder head, which in his opinion was a retrograde step for Bentley Motors.
WO in his autobiography states ”I declined as politely as I could to have anything to do with the top half, I don`t know anything about pushrods, I`m afraid, I said. I think you`d better get someone else to look after this cylinder head”. The implication here, is that because of the poor results given by the Weslake and Whatmough cylinder heads for the 4 Litre side valve version, the board had approved the use of pushrod actuated overhead valve gear for the cylinder head to improve the power output.
It`s difficult to comprehend why WO would refuse this task, as the design of the pushrod OHV should have been relatively simple for him, and certainly more in line with what he considered to be right. What were his reasons? Had he lost confidence? Remembering that WO was a conceptual designer and had relied upon Burgess, since the beginning, to produce the main design and detail work, as he had relied on Petty Officer Aslin in the RNAS. Now Burgess was sick and unable to help him, had WO lost it? Or was he just being stubborn, refusing to carry out work which he considered to be inappropriate. Whatever the reason, the other board members must have been very concerned by WO`s attitude, as this was a direct refusal to carry out their instructions. Under normal circumstances this would be grounds for dismissal , and there was nobody else to step in to carry on the conceptual design. Given the urgency of the project this was commercial suicide!
We can speculate that this was the moment that Barnato has hinted at, when the board actually considered letting WO go. Feelings must have been running very high at that time, but it`s difficult to see how they really could dismiss WO without damaging the company in the process.
Now we come to the appointment of Barrington as chief designer.
On the 24 th of August 1929 Ricardo received a letter from WO enquiring if Ricardo might be interested in entering into a consulting agreement with Bentley Motors. With the aim of jointly designing and developing an entirely new engine capable of producing a higher specific output in terms of horsepower per litre and pound of weight than had been possible in previous Bentley engines.
WO received a reply to the affirmative on the 2 nd of september. Later in September WO visited Ricardo at his premises at Bridge Works in Shoreham. We can speculate, that whilst discussing the details of the High Power Head which had already been fitted to a Chenard et Walcker with excellent results by CIS the joint patent holders, who owned the marque. WO mentioned that he was looking for a chief designer, as Burgess was terminally ill and unable to work. Perhaps Ricardo suggested Barrington as a possible replacement, as they were friends, and Barrington had probably mentioned to Ricardo that he was looking for a change of employers. And of course, as we have seen, WO knew him.
The timing is plausible, as there would have been just enough time from the middle of September to the 1 st of November, When Barrington started at Bentley motors, for the appointment to be aproved by the board of directors, the contract of employment to be negotiated, and Barrington to tender a month`s notice to his employer.
Bentley Motors waited until after Burgess`s death, announcing Barrington`s appointment on the 7 th of December, understandably out of respect to Burgess, who passed away on the 30 th of November.
Ricardo duly had some proposal sketches for the cylinder head prepared and sent to Bentley Motors, where under the supervision of Barrington, the production design drawings were prepared.
Again we can speculate that WO had boxed himself into a corner this time, as it is highly probable, that after the problems the board had with him, they chose to bypass WO, and communicate directly with Barrington about the design of 4 Litre. A cylinder head was made to suit the single cylinder test engine which was used to check the viability of the design before committing resources to the finished version.
There is still in existence a copy of the single cylinder power curve dated 31 st January 1930. the maximum power obtained was 22 bhp @ 4050 rpm. Multiply this by six and we arrive at a figure of 132 bhp, only 15 bhp short of a standard 6 ½ engine.The board must have been jubilant, what a result, with the possibility of even higher output yet to come. Poor WO would have been discredited and completely marginalised now.
This has been leading up to a question about why WO never mentions Barrington in any of his books? Possibly WO thought that Barrington had contributed to his and the company`s problems, and very likely they did not actually get on. This is not surprising given WO`s realisation that he had unwittingly relinquished his function in the company to Barrington, and no longer had any real say in design. Some sources say that they did not know each other. This is not credible as the Drawing Office was on the floor above WO`s office, they must have had some contact, assuming that WO still had some official areas of influence. Also at board meetings, WO would have been present, and probably posed technical questions when Barrington presented his progress reports. WO certainly would have had access to the engineering drawings, and as often happens, probably kept a discreet eye on things by going round looking at the designs on the drawing boards during the evenings and week ends, after the staff had gone. Frank Ayto the Chief Draughtsman would have kept him well informed of any happenings in the drawing office.
PRELIMINARY CONCLUSIONS
What conclusion can we draw from the above first episode?
The power output claimed by Bentley Motors for the 4 Litre engine was 120 hp at 4000 rpm. Comparing this with the power output promised by the single cylinder engine, obtained by multiplying the output of 22 hp by six, giving a total output of 132 hp at 4050 rpm, there is a discrepancy of 12 hp. So what happened to the missing horsepower?
The Ricardo design although potentially very efficient, was very new, and only the Chenard Walcker engine had been fitted with the high power head previous to its application to the 4 Litre.
With hindsight, Bentley motors should have used proven technology given the prevailing time and cost restraints. The reason the 4 Litre engine was not able to be developed to give the output promised by the single cylinder engine, was because the initial Ricardo design gave no latitude for change or tuneability, this would require a redesign of the block and cylinder head, but of course it was too late for this, Bentley Motors went into liquidation.
If WO had done as the board requested, and designed a push rod overhead valve cylinder head with four valves per cylinder, and spark plugs located at the top of the combustion chamber. The 4 Litre engine would have arguably then produced more power than with the Ricardo high power head, which is basically just a compromise between side and overhead valve layouts in terms of cost and performance. Also, very importantly, the OHV head would have been capable of further tuning and development.
We could take the view that Ricardo must shoulder most of the blame for the failure of the 4 Litre engine, as the design of the cylinder head was critical to performance, and was translated directly into design drawings by Bentley Motors drawing office from Ricardo`s design sketches. Basically, Bentley motors were doing the development work for Ricardo, on a design that was not yet fully proven. If the Chenard Walcker engine was so sucessful, why wasn`t this reflected in the 4 Litre? Ricardo`s engineers would have been in contact with Barrington, and as normal with a consultancy agreement, would have received the main layout drawings from Bentley Motors for their perusal. And would have duly reported back to Barrington, if in their opinion, there was anything untoward with the design .
Perhaps we should also blame WO for refusing to countenance the pushrod OHV, and agreeing to incorporate the Ricardo head. It is most probable that he was the one that recommended this course of action to the board, as there is no doubt WO had the start up meeting with Ricardo. This was a crucial and wrong decision which ultimately flawed the final result. As we know, there was only one chance to get it right, and they didn`t.
In the next episode I will reveal what I found in Ricardo`s Files when i visited their works at Shoreham. Also we will look at the design of the 4 Litre engine itself and try to resolve some anomalies.
Anybody owning a 4 Litre engine or who has experience of the engine or just interested please read my letter in ”Letters to the Editor.”
Below is a copy of the letter that I sent to the BDC Review editor at the same time as the article
Dear Richard,
Unfortunately the members who own 4 Litre Bentleys have the least technical support of any other model in the Bentley range. In the Technical Facts, only five pages are dedicated to the 4 Litre, and as far as I know, there are no other sources of information available. This is a situation which must be adressed.
I would like to contact anyone owning a 4 Litre engine. Who has owned a 4 Litre engine and has some experiences or knowlege to impart. Anyone that has any engine spares which could be used as patterns where drawings do not exist. Any Restorers or private individuals who have restored a 4 Litre engine. Anyone who has, or is making parts for the engine. In fact any information at all that will help 4 Litre owners in the future, to source parts and rebuild their engines.
I am prepared to collate any information supplied and make it available to all the interested parties, including the club, so it can be included in the Technical Facts.
It would be very interesting to know how many engines survive, so would all engine owners please please contact me with their engine numbers. These can be found on the front of the crankcase near the top of the timing case where the front cover joins it. Please also quote the crankcase part number. This will be found on the left hand side of the engine to the rear of the water pump stamped onto a square raised boss.
If there is enough interest it would be possible to form a little support group within the club as is done in the VSCC. Perhaps with an occasional newsletter.
Richard Evans has given me some information about problems with No. 5 big end, has any body else experienced this? I have in my posession a sump oil tray which has a repaired hole in it at the No. 5 rod position.
Dan Rens, the 4 Litre racer, is just finishing his engine rebuild and hopefully the car will reappear soon.
Yours Faithfully,
CLICK HERE FOR PART TWO