thank you for the comments and questions
Before I could call the cylinders complete, I though I should make the bronze valve cages and drill the remaining holes and tappings. I chose to make the valve cages in one setup to maintain concentricity to the valve guide. I liked how the plan called out a depth of the chamfer, and this was accomplished with my 1" dial indicator and mighty magnet setup instead of advancing the compound. Nicer finish I believe.
instead of pressing them into the valve block I made them a snug fit and relied on sister Loctite again. I bead-blasted the assemblies after cross-drilling the intake ports and plugging the visible passage way. The intake manifold connects to the bottom.
lastly the chamfer on the bottom of the cylinder sleeve was done and the head sealing surface wet sanded atop my granite surface block.
Crankcase Bearings
It was nice to do some simple mill and lathe work on aluminum for the bearing housings. This engine uses sealed ball bearings at each end and a bronze split bearing in the center. I built the parts per plan including the 4-40 flat head counter sunk screws that hold the bearing covers to the crankcase. I never realized that standard thread screws were 82 degree included angle and not 90 degree like metric ones. Luckily one of my hand held deburring tools is a zero flute 82 degree countersink. All the other bits are 60 and 90 degrees.
Started by drilling all the holes with the DRO and boring head in the mill vise. Then I indicated the rough cut square blanks on an expandable arbor and made them round.
Had to hold them on the outer diameter and dial in again to bore the bearing recesses and finish to depth. The bearings are a snug fit inside the holders.
Now it is finally time to bore the journals in the two crankcase halves. I had previously run a 1/8 ball end mill down each half to establish the centerline when I was milling the flanges and decking the mating surfaces. Used a heavy duty "angle plate" to secure everything directly on the mill table so I would have Z axis room to use my longest boring bar. Indicated on the 1/8 center witness point using magnification and a wiggler. Verified everything was square and plumb with respect to the mill axis'. I was able to reach both the end and center web of the crankcase. I also drilled the camshaft and rocker arm pivots in this setup. Lastly I reduced the cruddy looking extra roundy end of the camshaft support and it looks a lot better compared to the other end. I left extra because of the perceived inaccuracy brazing these on the crankcase. Still have to repeat on the other side of the crankcase.
Quit early so I could order some 4-40 x 1/4 flat head screws and share this weekend's work.
Happy Veterans Day weekend to all that have served this great country!
