Delage GP engine 2

DELAGE GRAND PRIX ENGINE PROJECT

Part two by Mike Sayers

These are the first CAD layout drawings of the front and rear elevations with help from stepson, Paul, who took the original pencil drawings and sketches and converted them into really good CAD drawings. Everything is accurately dimensioned. When a CAD drawing is set up correctly any dimension required can then be accessed.

Below: Side elevation and section through the front cylinder; twin overhead cam engines always have a very bulky cylinder head. The ports are at 50° angles. It is a very awkward shape with no two faces parallel to each other and all at angles other than 90° making mounting for machining unusually difficult.

The idea was to rotate the part about point A. The starting point will be a piece of cast iron roughly shaped to the section. Then a mounting diameter at point A, will be machined with a centre in it, at both ends of the block. The block can then be mounted in the dividing head of the milling machine, and it can be rotated around axis A-A. Each face can then be brought to bear under the cutter. That will account for all the major faces and the hole drillings. The whole job can then be done in the dividing head between centres. It is going to be a complicated job, but it is achievable. The only concern is the water spaces. On the inlet side hardly any water space exists around the port and, fortunately, there is little need for any on the model. On the exhaust side it is different. There are large water spaces at C and D. These can only be replicated by drilling the largest diameter holes that will not break into the exhaust ports along the full length of the block. Holes should then be able to be drilled between the cylinders to communicate with the major water spaces and outlet points.
That is the approach decided upon. The block has a larger volume of material than the Bentley, so the preheating arrangement will be the gas barbecue which will be cleaned thoroughly, and also a digital thermometer to check the temperatures of all the metal parts. The silver soldering will be done in the same manner as for the Bentley using oxy-acetylene. It will be a bit more awkward with the cooling down phase, being gas fired, but it will have to be done in the best way possible.

Part one here. Part two here. Part three here.
Bentley series starts here.

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