Once the rough cylinder bores were made and had their faces milled to the proper height from centerline a boring head was used to make the proper diameter bore. The bore was about .005 - .010 oversize to allow for cylinder distortion. I've heard that people who make the bore too tight end up breaking their cylinder base at disassembly time because it distorts and clings to the sides.
A ledge or counterbore was made to help center the cylinder spacers. (Arrow) Female threads for the cylinder studs are helicoiled. Might as well do them now rather than later when oneof the studs pulls out of the soft aluminum.
My case will have pressure lubricated tappets riding in replaceable bronze liners. The counterbore in the lifter bore is for an oil seal. (Vee packings) Coming up with a sealing arrangement that works with stock components took some head scratching. VW stock valves leave about .45" clearance between the valve tip and the case - NOT a lot of room to work with! Things would have been much easier if I chose to have custom valves made shorter than VW valves. Ease of repair using readily available parts is one of my design objectives. My design dilemma was keeping valve lash adjustment simple while maintaining oil containment. Since the valve train will be enclosed and the Vee packings need to be held down figuring out a servicable solution took time. This is one of the reasons this project is moving forward at a snails pace. My solution to the valve adjustment is to use replaceable hardened discs of varying thickness rather than a locking screw.
Once everything was finished I was dying to see what the finished product would look like. A cylinder was plugged in and a chunk of aluminum resembling the head was laid on top. It's really amazing to see how small the diameter of the engine is. It's easy to forget the engine's details when you get to see one once a year. (HCI at Sun n Fun) Most radials we see are too big to wrap your arms around. (Too heavy too) This one can actually be hand mounted providing that your back is in good shape. (Not that anyone would want to do such a thing)
