"I managed to stand a £1 coin up the Raynaud’s floorboard whilst running!"

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The Expert Explains…

Last year during the London to Brighton Run our eyes caught this Raynaud. An imposing and grand Vis a Vis, which comfortably takes 5 people. We talked to the owner, who told us about the background of the car and the preparations they made to the car to cover longer distances with it.

The Raynaud was built by an electrical engineer in France who we believe only built this one car. The Vis a Vis has solid tyres, a steering wheel and a four-speed gearbox controlled via a second steering wheel. It has two separate single-cylinder engines, horizontally mounted, whose crankshafts are directly coupled within a common gearbox. The entire assembly mounts in the rear of the car with each flywheel mounted outboard against the chassis side rails. Singly, the engines have a capacity of 2 litre resulting in a total capacity of 4 litre.

Jonathan Wood, an expert in the restoration and maintenance of vintage and veteran cars, who has been working on the Raynaud, explained to us how he prepared the Raynaud the famous run.

“On paper, the car appears very capable. However, we were aware that the engine design/layout was potentially flawed, as the car has a history of breaking crankshafts and has never participated in an event or rally in recent years due to its fragility.

At the outset, we set about running the car to understand the vibrations involved and plan the work required. It was immediately evident that the vibrations were severe and during the subsequent dismantling process, we realised that there was no rigidity in the mountings between the two engines and gearbox, resulting in a need for massive clearances to accommodate misalignment and flexing. The crankshaft also had evidence of numerous weld repairs and interestingly, the two engines which we had assumed were identical, were not, they differed in bore size and valve size!

The engine overhaul commenced by matching the bore and valve sizes to ensure an even output from both units. We then concentrated on the bottom end having two clear aims. Firstly, to produce a new counterbalance crankshaft (to reduce vibration) using modern materials to increase strength.

The second was to improve the engine mounting, adding rigidity to ensure and maintain better alignment to allow more regular clearances to be used. An important consideration in the car's overhaul was to ensure the design remained true and faithful to the original. All changes had to remain sympathetic to the original design.

Due to the car's history of regularly breaking crankshafts, we opted to couple the crankshafts together using a low-grade material, splined shaft. This was an intended weak point to protect the new crankshafts. We also opted to remake the lower gearbox casing in steel, providing rigidity and positive location for the engines. The first session of road tests progressed well and following approximately 90 miles of running, without warning, the crankshaft coupling sheared. At the outset, we had concerns that the crankshaft assembly was very long (being as wide as the car) having a flywheel on each end with no support to the middle of the shaft. We, therefore, opted to introduce a centre main bearing at this stage to further add rigidity. In addition to this, we also introduced a flexible drive coupling, having what we thought was ample capability to handle the forces and stresses involved. However, this proved a mistake as the coupling only lasted a matter of minutes running, so this was replaced with a similar spline shaft as previous but maintaining the new central support bearing. Again, we continued to road test the car believing we had overcome the crankshaft weakness.

However, in 2018, on the London to Brighton Run, the crankshaft coupling shaft broke at Crawley. Having now employed all practical improvements we felt necessary, I engaged a consultant engineer for advice on how this issue could be resolved. Wishing to avoid numerous reworks we opted to employ one single modification which would overcome this issue and so we decided to consider a dual-mass flywheel conversion. We provided the engineer with weights and dimensions, of all rotating and reciprocating components, who conducted an analysis using a computer model. The conclusion being that he could reduce the crankshaft period by 30% if using a dual-mass flywheel of the same dimensions of that originally fitted to the car. We felt this was a significant improvement, so commissioned the production of the flywheels as recommended.

Following the initial engine overhaul, I was impressed with the smoothness of the engine and have struggled to understand how the vibration in the engine could cause the failures we were encountering. However, it was immediately apparent, upon running the engine, with the dual mass flywheels how much smoother this was. During an early test run with the car, I managed to stand a £1 coin up, on its end, on the car's floorboards whilst running! I also have noticed that the engine is much quicker to pick up when revved and a notable performance gain is present on the road. These were unexpected but welcomed advantages.

Last year's London to Brighton proved to be very rewarding, as not only did the Raynaud complete the run but did so with a surprisingly good turn of speed impressing both myself and the owner, Mr Holmes. It has taken a huge amount of work, commitment and brainpower to get the car into a reliable and usable condition and we are delighted to have been part of this project.”

Mr Holmes added to this that "despite the issues highlighted the achievement of M Raynaud in building this car at all in 1896 was remarkable. The car is a delight to drive and the gearbox remarkably easy to use. The only change to the gear box set up was to incorporate stops. Under the original system there were no stops and the gear wheel could be rotated continuously in either direction. It was a nightmare to keep mental track of which gear you were in and in which direction to turn the wheel. That is now behind us and subject to a certain virus we are looking forward to this year's Brighton."

We would like to thank Mr Holmes and Jonathan Wood Vintage & Thoroughbred Restorations Limited for this detailed explanation.

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