Engine block gets a fix

I’m turning my attention to the engine block, which is built in Section 6 (while I decide on paint colours and prep some body panels). The block is built from a stack of 9 layers made up of 15 parts. in Section 7, the stack gets sandwiched between a base plate (part M304 if you’re playing along) and a top plate (M286).

And so, I found a problem: my initial dry fit of the stack of engine layers shows that the block doesn’t seem to assemble long enough: fitting the stack into the sandwich (picture below left) shows a big gap, later measured at 1.5mm. Test fitting some other components – the inlet and exhaust manifolds – shows that the base and top plates are correct, but the stack is too short. When spaced out using the manifolds, the stack fits in the sandwich (below right), which suggests the fix is to shim out the stack. Spacers are needed faily evenly along the length of the stack of layers.

I decided to shim in four places where the shims would not interfere with the combustion chambers, so the shims will be placed in two groups, between the 1st and 2nd, and the 3rd and 4th rotor. This means they will be attached to parts painted ‘Steel Metallic’ which is a bit darker and should hide them a bit. I tested another dry fit using four 1/64″ scrap shims (1.5mm / 4 = 0.375mm = 0.015″; 1/64″= 0.016″ so that’s pretty close, see below left). The shims will all be the same shape, so I stuck a vinyl template to a stack of 0.016″ thick aluminium plates and made four of them (below centre and right).

Note the template for the shim is in my annotated instructions (Visio file, see page, A – Patterns) on the Documentation page.

One more dry fit with the shims fitted and most of the cleanup of the engine block parts done, and it looks good.

Note that a couple of pipes that fit between various layers in the stack will need some minor mods to fit corretly. There is an oil pipe (M199) which can be bent to be a bit straighter, and the inlet pipe from the turbo (M142) will be lengthened a small amount with some solder.

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