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Wow am so jealous. Always wanted (or should that be) to build a between the war race replica or the old habit of putting a period aero engine in to a period chasis.
Who did you use to make the head? How did they do it, copy of the iron head?
Would the engine develop more power if made using newer material and closer tolerances? Or is the engine unique enough to be quite close tolerance?
Congrats and I am very green eyed.
lynx-
Dropping aero engines into pre-ww1 chassis is great fun but it is difficult to do well from an engineering point of view. i like to preserve the engine so it could go back into a plane (unlikely i know but some of the engines are getting very rare, particularly the big V8s and V12s). You also have to isolate the engine from all chasis flex and twist as they usually mount on very thin cast flanges. In an aircraft the plane tends to roll or pitch rather than send twisting forces through the crankcase. I have a V12 here that makes 900plus HP and more importantly 1200 lb/ft of torque at idle. it has a cast aluminium crankcase with a flat flange running the length of the engine on each side that is less than 20mm thick. if you bolt that to your pre 1918 chassis you will be expecting it to act as a stiffener for the front third of a very floppy steel frame!
The 39 car: Head is similar to the cast iron one. Fortunately we have drawings. Patterns are made in wood and resin. Lots of them. Some of them are for molding cores to go inside the head others give the outside shape. They all fit together like one of those old school wooden puzzles that you make into a cube etc. I think pattern design and making is some of the hardest stuff to get right that I have had to teach myself / learn to understand enough to talk to the guys that do it all day every day.
For actual casting we use NewPro Foundry in Hayes. brilliant attitude to nutters like me. Machining - I do it, some of it is done by a neighbour & friend who is a retired tool maker, other stuff gets farmed out to recommended specialists.
We are working to achieve factory power output - that's quite a bit, more than twice the production road cars. Also the factory cars were originally designed to last out Le Mans. By 1940 they would have been obsolete so long term durability was not an issue.
There are very few "modern" materials in my engine. Most of it is an exercise in blueprinting. I suspect some of our work will give greater long term reliability and or durability due to the precision with which thinks are being fitted. One of the problems with using old parts is that a failure (say a con rod) can be pretty catastrophic. So we have arrow rods and forged pistons. We are still on original compression, capacity and rev limits but we expect, even with hard racing, to get a few thousand miles between inspections. the rods are on modern shell bearings but the mains are old school white metal. We have added modern full flow oil filtration. The engine already had full pressure feed and an oil cooler but no filter. When I have raced cars without filtration in the past the only way I have got good bottom end life is to change the oil after every race meeting.I still do that with my vintage motorbikes. Having spent many £ks on this engine I do not see any point in not having a full flow filter.
Today's jobs : Decide how to go about making a new reproduction drop arm for the steering box - the old one and spares all showing cracks when magnafluxed.
I stripped down the water pump to check everything over. All looks pretty good, ordered new ball races (fortunately a common size). Now I have to work out if we can get a modern seal to stop it dripping water. The original system had a steel shaft running through a long bronze bush with grease being pumped between the 2 to stop water seeping out. I have yet to see a car on which this system reliably prevents water coming down the bush and on my engine when that happens it goes all over the ball races.
Enigmatic
The cars are essentially modified Delahaye 135s. It is a complicated story. The stroke was shortened to reduce capacity to below 3 litres so the Delages could race in the 3 litre class leaving Delahaye to fight Bugatti and Lagonda et al for overall honours without the threat of being beaten by one of their own cars wearing another's badge.
It didn't go quite that way though. Delage led for much of the race until the exhaust manifold casting broke letting the Bugatti through for overall honours, Delage 2nd and first in class.
There were only two racing 3 litres both survive but are rarely seen in public. Neither is as it was pre war. Road going ones were also based on Delahaye 135 but are also very rare. Post war 5 single seaters were built and 4 survive. Under the bodywork they are very like the pre war cars.
My car was found in France. It was a chassis axles and engine. It is within a few numbers of the Le Mans cars and must have been one of the last ones produced before the outbreak of war. We don't know what body it had but probably a 4 door saloon. We have done what the factory would have done - taken a chassis from the production cars and built a racing car. The hard part has been trying to make it exactly as the factory racers in 1939.
Rear axle is a special competition one with a lot of alloy casting replacing cast iron. Live axle on semi elliptic leaf springs. Gear box is an MK35 Cotal. Engine is a 3 litre straight 6 almost identical dimensions to an Austin Healey 3000. Rev limit 5500. Compression 10.2:1. Arrow rods and Ross pistons. Cylinder head is aluminium - the car had a cast iron one when found we made a new one.
Front suspension is independent the design is known as System Talbot and was used by a number of cars including Talbot Lago. Shocks are Repusseau friction. Again these are unique to the 2 racers so they had to be made for my car.
Fuel tank is large and is shaped around the back axle - yes we had to make one of those.
Couple of departures from original to make it a bit user friendly on the road / legal for racing. There is a mount inside the tail so I can carry a spare wheel and there is a plumbed in fire extinguisher - HD44 Solex carbs are legendary for their fire starting abilities.
Finished weight ready to drive should be sub 900kg and top speed 130 mph+