How I built a Porsche engine | Thank Frankel it’s Friday

I can change a wheel and the oil of all my old dears save the Caterham whose oil filter always seems to overtighten itself. I can remove and clean spark plugs and once replaced a set of HT leads, an achievement of which I am perhaps more proud than I should be. But anything more, even something as simple as changing a set of brake pads? Forget it.

But this Christmas I did it all: conrods, pistons, crankshaft, cams, camshafts, rocker gear, valves, valve springs, gearing it all together, making sure I’d got the timing right and, and and… sometimes I wish this column didn’t come with pictures attached because I’d back myself to get to the last paragraph before you twigged this was a model engine out of box, not a real one out a car. But as you know that already there doesn’t seem much point.

Yet still I am proud. Because I really did think assembling my wonderful Christmas present from the aforementioned missus really would be beyond me. Because this was not just a static exhibit: if I got it right, when I pressed the button on its stand, all those moving parts would go into action, operating in precisely the same way as a real 911 engine. And yes, it was always going to be the Porsche flat six, not just because it’s my favourite engine, it’s also air cooled which meant I wouldn’t have to do any plumbing either.

After I’d laid it all out, I was more daunted still and frightened already of that moment when I’d finished, pressed the button and nothing happened. Because I knew I lacked the skill, patience and energy to try to unscramble such a hideously complicated egg.

So I got to work and much to my surprise it was manageable. Not easy by my standards, but I progressed and soon I had rods on a crankshaft at one end and pistons on the other already snugly tucked into their cylinder bores. If I turned the crank by hand, they shuttled back and forth most satisfactorily. Which is when I started to get cocky, and the precise moment it all started to go wrong.

Instead of obeying the instruction manual, I interpreted it, doing some things in a different way, others in a different order, because there seemed no reason not to. But of course there was. And when something didn’t work I never knew if the problem was with that component or the one assembled far earlier in the process upon which it was supposed to act. Four times I got to the point where I genuinely thought it was going in the bin. And four times, reversing my steps to the beginning of the previous stage and doing it as Porsche instructed, I felt my heart soar as pieces slotted precisely into place. Because, and I know this will surprise you, Porsche has a better idea of how to put together even a plastic 911 engine than I.

And so it got built. The hardest parts? Once I’d stopped tiny valve springs leaping like grasshoppers out my fingers to be lost forever in the carpet pile (Porsche isn’t stupid, it provides a couple of spares), it was the assembly of the cylinder heads, specifically getting the rockers to act on the cams and then getting the timing right.

But on the third day – I’ve read somewhere that it can be done in three hours – I’d done all that, bolted on the cam covers, attached the entire decorative manifolds, exhaust bumps and injection trumpets and was ready. There was a slight delay as three viable AA batteries were found, but at last the moment of truth was upon me. I plugged in the lead for the engine and another for the sound synthesiser, held my breath, shut my eyes, pressed the button and… bugger all.

Actually that’s not entire true. One LED sparkplug illuminated, shining a thin orange light on my incompetence. But that was all. So deluded was I, I convinced myself the batteries were duff after all and walked all the way to the village shop to buy some more. They made no difference. Pressing the button again created a rather tinny sound of a synthesised 911 engine going through the revs, but without the accompanying movement of the engine’s internals it was pointless. In fact it was embarrassing.

I’m not quite sure what made me remove the power cable pin and plug it into the as yet unused hole next to it, which I knew to be nothing more than a headphone socket. Desperation I guess. But suddenly there was a whirring sound and, to my utter astonishment, I saw a crankshaft start to turn. I saw pistons move and spark plugs spark as they reached top dead centre. Peering even further in, I could see valves sliding, springs compressing, camshafts turning. To no-one’s greater amazement than my own, it worked perfectly.

So I think I now need to build an actual engine, one in which real combustion takes place. I’ve always been rather taken by those single cylinder static engines you see at country fairs, so that’s what I’m going to do next. And if you think I was proud of building a functioning plastic Porsche engine, just wait until I’ve done one that is actually, well, an engine.