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I have made the twin carburettors to the drawing for initial running. I intend to fit this engine to a model DH51, for which I have designed a manifold for a single carburettor which will lie horizontal over the timing gear housing.

A simple tube bender was made per Erics drawing and the induction tubes bent, trimmed to length and soldered to brass flanges and T pieces.

Rocker pillars and exhasut stubs are from steel. With the parts so far made, it's starting to look like an engine!

The materials kit from Hemingway included valve springs, so I didn't need to wind them as I have dne for previous engines. Valve caps are from aluminium and the tiny C clips from silver steel and hardened.

Tappet adjusters were made from 10BA cheese head screws with sockets for the pushrods cut with a 1/16" ballnose. A bronze bush was pressed into each rocker and reamed to finished size.

Another simple rotary table fixture was used to machine the steel rockers. Note the roll pin which allows each rocker to be returned to the fixture in its original position for subsequent machining operations. The heel radius was formed by moving the fixture on the rotary table to bring the...

Valves are made from 316 stainless steel. They were initially roughed out in a series of steps, then stress relieved before final turning with the slide rotated so that the seat face can be finished at the same setting as the stem diameter.

In order to ensure that the cooling fins would align properly all the way round, I made a fixture block to raise the parts high enough above the vice that I could cut fins on all four sides at one height setting. In another devaition from Erics design, I made the heads 1/16" taller than drawn...

The cylinder heads appear highly complex, but once they are broken down to a logical series of operations, there's nothing particularly challenging in them. I made a D bit to cut the small radii which give the appearance of four seperate heads.

Pistons are straightforward turning and milling.

The rods were made in a conventional manner, using a simple fixture on the rotary table. The shells are fitted with Locitie 620. Note that they are slightly rotated relative to the split line of the rod. This helps with alignment of the rod and cap on subsequent assembly.

The drawings show split connecting rods with bronze shims in an Omega shape foming the bearings. In a departure from Eric's drawing, I decided to make conventional bronze shells. I split some bronze bar in half along its length with a slitting saw and clipped the halves together in the 4 jaw...

The cylinders are from EN16T. The fins are formed using a 0.020" wide grooving tool, which I ground on an HSS parting tool. I am fortunate to have access to a surface grinder, which makes it a lot easier to produce the correct clearances. The bored were finished with an expanding lap, made from...

The camshaft blank was turned from silver steel. A fixture was constructed to time the 16 cams correctly. It took me some time to understand the way Eric Whittle had chosen to number the cams and then differently number the dowel positions on the fixture. The drawings call for the camshaft to be...

More crankshaft turning operations: Reducing the webs and the finished crankshaft.

I chose this engine specifically because I thought it was beyond my skill level. I do try to pick projects which will force me to learn new skills and improve existing ones.

A small eccentric clamp at the end of the crankshaft provides centres at the two journal offsets. The flat allows for accurate repositioning of the crankshaft when it is moved along for the next journal.

The crankshaft was roughed out on the mill, leaving the journals square.

The crankshaft is first turned as a blank, with both ends left oversize. An eccentric turning fixture was made to support the crankshaft while machining the journals.

To ensure that the centre main bearing is concentric with the ballraces, it is finish bored with a bar which runs in the ballraces.