Building up the Aerovee engine block

To some people, the thought of having to build your engine for your aircraft that you are building as well just seems crazy. I actually happen to agree with Jeremy Monnet's philosophy in this regard, as it gives you a greater sense of satisfaction and knowledge regarding maintaining and understanding the power plant.

The first stage is assembling the crankshaft. As this engine is highly modified from the original 1200cc VW unit and uses a custome crankshaft and rods to allow for the increased bore and stroke it means that the clearances inside the crankcase are very close. Aerovee machines the cases but depending on what conrods have been supplied from the race shop depends on how much the rods have to be machined to clear the camshaft. The AD gives the dimensions regarding how much metal has to be machined off, which I must admit I found a little scary. I chickened out and took the bare minimum off and then tried the crank in the cases. Naturally I should have just followed the instructions to the letter and then I would have avoided pulling it out again a couple of times until the desired 0.045" clearance was achieved between the camshaft and crankshaft. I found that I had to machine the centre main bearing location hole as well because the shell didn't quite line up properly in the case.

So far I have spent 7 hours with the result that both the heads are on with the valve push rods installed on the right side. These require a bit of work in order to machine them to the right length depending on what compression ratio you set the cylinders to. I have erred on the side of caution, which means that I 'rounded' down the compression ratio. It would have ended up slightly higher than 8.0 to 1 so I have made it a little under just to play it safe.