Rolls-Royce and the 8-litre Bentley

It is well known that in 1930 Rolls-Royce was alarmed at the performance and appeal of WO Bentley’s fine 8-litre model, which was in direct competition with its Phantom II Rolls-Royce. This was overcome by buying the financially ailing Bentley Motors in a carefully disguised deal, and later on by refusing to let WO use his name on a Lagonda he had designed. The closure of the old Bentley Motors Company meant that the production run of 100 8-litre Bentleys came to an end and R-R were able to produce the new ‘Silent Sports Car’ based on 20/25hp Rolls-Royce components without rival or hindrance.

Before that happened, however, Rolls-Royce Ltd reacted to what they saw as a serious threat from the 8-litre Bentley.

In November 1930 Percy Northey, the long-serving R-R test driver, had business at Brooklands from where he returned with WO Bentley (whom he calls ‘Willi’ Bentley) in a new 8-litre. He was, he reported to AF Sidgreaves, MD of R-R Ltd, more cheered up than otherwise, by the experience. This was presumably because he noticed that the radiator of the Bentley ‘jellied’ as they drove along the Kingston-by-Pass, in the same way as R-R had suffered with the PII, and it was obvious that WO was much concerned. The 8-litre’s engine was quite reasonably free from vibration but there was a familiar boom at about 52 mph in top gear, but it was kept within reasonable bounds, unlike a similar problem with the PII engine. Moreover, the hypoid back axle was not quiet; WO admitted to Northey that there was a noise from it at 40 mph. The 12 foot wheelbase chassis pitched, was uncomfortable when running along the Kingston-by-Pass, and the Bentley was not as quiet as a Rolls-Royce PII, although there was less periodic body boom.

It is interesting that Bentley was happy to give Northey a lift to London, although he did not offer to let him drive the new car. Apparently only two 8-litres had been made at the time, so this was an experimental car, which was noticeable to Northey by the mass of dials on its fascia, five of which would not be needed in a standard car. (Deliveries of the 8-litre did not commence until 1931).

Any consolation that Mr Sidgreaves derived from Northey’s communication was dampened when HH The Maharajah of Rewa called on the Sales Department to tell Mr McKechnie of the Conduit Street sales staff that he was taking his PII back to India only because he could not get a good price for it in exchange for an 8-litre Bentley. (“The richer they are, the more careful with their money!”). After driving all kinds of cars, including the Mercedes and the Bentley, he decided the latter was the best car he had ever driven, far superior to the PII in every respect. The Maharaja told R-R that unless they had a good answer to the 8-litre Bentley they would find themselves ‘not in the premier position’. He felt that after they had driven it, as he had at 100 mph, the Indian Princes would buy 8-litre Bentleys. (In fact, none did, although at least four new 6 1/2-litres had been sold to Indian potentates).

This aroused Sidgreaves to write to Mr Royce (not then knighted), saying the 8-litre was becoming a formidable competitor to the PII. He quoted the remarks of the Maharajah of Rewa, said there had been other comments of a similar nature, and reminded Royce that he had borrowed a six-cylinder Bentley for test from a coachbuilding agent in the early days of the PII, and that Hives and Rowbotham, of the Experimental Department, had found its engine extraordinarily good in respect of smoothness and torque (curiously, the Rolls-Royce MD, although so concerned, described the Bentley as a ‘6-litre’ instead of a 6 1/2-litre). He reminded Royce that his suggestion to buy a Bentley and examine its engine had not met with the great man’s approval. The MD told Royce that many things about the Bentley were nothing like as good as those of a Pll but that the 8-litre engine was superior and he did not think any of the R-R technical people had tried one. Perhaps Royce had implied that he did not like secret trials of competitors’ cars, because the next development was a letter from T Barrington of Bentley Motors Ltd saying he would talk to WO and that if a visit was made to Cricklewood, while Bentley might not be about and the R-R visitors would have to take ‘pot luck’ as to the cars available, the Bentley people would like to try a real Phantom Rolls-Royce. This was a sort of ‘exchange-drive’, better thought Barrington than ‘back door methods’.

So at the end of January 1931 EW (later Lord) Hives and AG Elliott from the R-R Design Department arrived at Cricklewood with the latest Continental PII which possessed one or two special features not yet on the production cars and was being taken down to Royce at Le Canadel a few weeks hence. They also told Mr Barrington that if a London trial car was preferred, this could be arranged at any time. In return, they came away with an 8-litre Bentley. Opinions on it were dispatched to Royce, but most of the comments by Elliott do not seem very profound. For instance, he noticed the long distance between the rear crankshaft bearings flanking the camshaft drive eccentrics, saying the extra length of the shaft would be a disadvantage but was presumably made up for by the diameter of the additional portion and the double bearings. Similarly, Elliott told Royce, “There is a wheel flying round at the front between engine and dynamo which might be some form of slipper with the amature as a damper, as it would be unwise to couple the latter direct to the crank”. They were impressed with the 8-litre’s ability to rev. WO told them the master vibration period was at 3800 rpm (111 mph) but he had run up to 4400 rpm. The R-R testers had got to 75 mph in 3rd gear, thought to be nearly 3700 rpm (no tachometer?) and the engine was remarkably smooth, both driving and ‘over-running’. Slow running was not good below 10 mph but this was blamed on the SUs (‘which have a tendency to be sloppy when closed down’). The 13ft wheelbase Bentley had the worst pitching at low speeds ever encountered on a big car, but in spite of soft suspension it held the road well at high speed. The front shock absorbers were Hartfords, with additional friction discs at the frame and axle anchorage points (this is new to me — WB), the rear ones hydraulic.

The next blow for R-R was when Jack Barclay, the well-known agent, said he had difficulty in selling the Continental Pll against the 8-litre Bentley, which would do 100 mph with a comfortable saloon body. Hives was sceptical and got Barclay to meet them at Brooklands with his Bentleys, a 6 1/2-litre and an 8-litre. R-R replied with 27EX with twin carbs and the compression ratio up from 4.6 to 5.0 to 1 and 26EX, the prototype Continental. All four cars were saloons. Timed over the half mile with cut-outs open the 8-litre Bentley did 99 mph, the 6 1/2-litre 90 mph, 26EX 83.5 mph and 27EX 84.9 mph. The respective lap speeds were 97, 87.2, 83, and 83.7 mph. The 8-litre was geared at 88 mph at 3800 rpm and the Royces at 79 mph at this engine speed. The R-R’s had to have electric Autopulse pumps to supplement the Autovacs.

Some side-by-side acceleration tests then occupied this day in April 1931 (useful old Brooklands!) which showed the 8-litre better on speed and acceleration than the standard Continental PII, the 6 1/2-litre Bentley faster but not quite as accelerative as the PII. Hives concluded that the 8-litre Bentley was the best competitive car they had tried, far more impressive than eight, 12 and 16 cylinder rivals; at 75 mph the Bentley’s absence of roar or fuss was ‘very remarkable in comparison with the 12-cylinder Maybach’.

The reply to all this from Le Canadel emphasises what a wily old engineer Sir Henry Royce (not yet knighted) was! He said the results did not surprise him. They should expect a Bentley to beat them on speed but in the past (this was April 1931) they had been poor town cars. He had heard of valves, steering, bodies, repair costs, life and permanent silence going against them. As for power, they could hardly hope to beat the four-valve job but twin carbs, a slightly higher compression ratio, and a long duration camshaft would get nearer to it. Royce said many times he had been very dissatisfied with their maximum bhp. He then went off at a tangent, professing ‘a supercharged 12-cylinder the real thing to do’ — so there could have been a Merlin under the bonnet!

Hives spoke to Mr Royce about borrowing a blower 4 1/2-Bentley (to examine its supercharger) as well as an 8-litre. Discussing crankshaft vibration periods, the wily Royce reminded his engineers that you had to run 10,000 miles before looking for this, and the Bentley they tried was probably a newish car. He thought the R-R damper so lightly set it could not be very effective, and had had designed a new dry centrifugally-loaded damper for them to try. Royce remembered the old 30 hp R-R with 1.5″ crank and cast iron pistons and thought it must have passed the master period with its very tight friction damper.

Hives retorted that while the Bentley period was not as bad as the Pll’s, they were in a worse position as it came within the car’s speed range, whereas the 8-litre’s was outside the speed range. A R-R crankshaft failure on Brooklands was due to heavy balance weights. R-R was keen to know how Bentley got over a weak crankshaft. They found the fabric dynamo joints gave some trouble and were destroyed after running through the period several times and slack developed in the damper serrations, with loss of damping efficiency. Hives noted that the 8-litre had 2 1/8″ crank journals, the 4-litre 3″ dia journals, and that on four Bentleys tried the carb needle valves restricted petrol flow so that the engines could not reach the critical period in top gear. Elliott told Royce he did not agree with Day the chassis designer and Evernden, assistant chief engineer, that an 8-litre was rougher than a PII, as the former had only been taken round Brooklands in one at 90 mph and the latter had never tried one! The testing of a Bentley went on, to the extent that Hives reminded his MD that the 8-litre had done 18,000 miles and showed some wear and tear, piston knock was pronounced, and the back axle noisy. He didn’t want to be blamed for this when returning the car!

That concludes this summary of correspondence in the R-R Memorial Foundation’s files relating to the 8-litre Bentley v the Rolls-Royce Phantom II. (After the take over of Bentley R-R was concerned with developing the Derby-built cars to replace the old 3-litre and 4 1/2-litre Bentleys, allowing the Pll to meet the requirements of former 8-litre owners.) With hindsight, the 8-litre Bentley engine has been far more of a competition power unit than ever the R-R Phantom was, pace, even today, the exploits of Stanley Mann, Tim Llewellyn, Keith Schellenberg, et al.

(I am indebted to Ken and Mermie Karger, Editors of The Flying Lady magazine of the Rolls-Royce OC Inc of America for allowing me permission to use material from the R-R Foundation archives which the RROC’s past President Ted Reich had extracted.) WB