Before starting on the bottom end assembly, the motor mounts were machined to support and help steady the block. A baseplate will come later after I've finally decided between a fuel pump and a conventional gravity fed tank. The mounts could have quickly been made from angle stock, but with none on hand they were wastefully machined from thick bar stock. After bead-blasting they were gold anodized using the home anodizing setup described in my Offy build. While the chemicals were still laid out, the bell housing was clear anodized to darken its color and to reduce the chances of oil and grease stains later on.
But, the anodizing didn't go smoothly this time. The two front mounts turned out great on my first try, but my beginners luck ran out on the rear mount. Initially its color was off just a bit, and not knowing any better I decided to re-do it. After again bead blasting and etching it in lye, I wasn't able to get an anodizing current to flow through it. I expected the problem was likely a poor electrical connection to the part which in my experience in an ongoing problem with this process. However, nothing I did including replacing the electrolyte and wire brushing the lead electrodes would reestablish current. The unregulated power supply I'd been using had a maximum output voltage of some 24 volts, and my typical 1-2 amp anodizing current was well within its capability.
The part's surface was redone a third time and with multiple electrical connections but still no joy. Finally, switching to a constant current supply with 2X more output voltage solved the problem, but strangely it had to be cranked up to nearly 50 volts to get 800 ma. of anodizing current. After 20 minutes in the tank I noticed the part had taken on a slight golden tinge similar to its original color. After the color dip and sealing steps, ohmmeter measurements showed the part was finally anodized, and its color was as nice and uniform as I could ask for.
I couldn't find any online discussion about what I'd run into, but I had a suspicion the subsequent bead blasting's hadn't removed the entire initial anodized layer after all. Although my ohmmeter measurements had indicated zero surface resistance, my probes were making contact to only a relatively few microscopically high points that had actually been cleaned off by bead blasting. This tiny effective area wasn't indicative of the entire part's surface, and the very thin insulating islands remaining between them required a high punch-through voltage in order to get significant current flowing. After thinking about it, I was amazed that the part turned out as well as it did.
During assembly, the ring'd pistons were attached to the crankshaft through the top of the block. The shop-made installation tool shown in one of the photos was used to eliminate potential damage to the rings. The dimensions of its two-piece design aren't critical, but the i.d. should closely match the piston's diameter. An o-ring held the halves in place around the piston and the rings squeezed down inside their grooves so the piston could be safely slid into its cylinder. The only tricky part was lining up the rods with their journals inside the narrow spaces between the crankshaft webs.
With the crank fully assembled, the block was sealed to the pan with a two-piece .015" thick Teflon gasket set. Adhesive backed vinyl was used to seal the pan to the front and rear main (ball) bearings. The shape of the flywheel along with the rings' friction will make it awkward to precisely position the crankshaft during timing adjustments. So, the adapter that will eventually be used to drill start the engine was machined next since it can also be used to manually rotate the crank.
The drill starter consists of a machined body into which a one-way clutch was pressed. The inner bearing for the clutch was machined from drill rod and then hardened. Its hex shaped end matches the socketed rear of the flywheel. The inner bearing is loosely retained to the body with a 6-32 SHCS. - Terry
