Some more supplies came in late this past week and I was able to start work on the cylinder heads.

Some 3" carbide burrs and a porting kit from Eastwood.

I worked on the #8 combustion chamber, polishing the bulk of the casting texture out and blending the transition into the intake valve seat.  This required a very steady hand, with the sandpaper in some instances only a few tenths of a millimeter away from the valve seat, spinning away at a few thousand rpm.  I didn't bother to get all of the texture out, as any material removed is effectively reducing my compression ratio.  Following the sandpaper rolls on the die-grinder, I wet sanded by hand with #220 grit and then polished it to help reduce the rate of carbon build up.  As a final step I broke the edges of the bowl with some scotch-brite to help prevent detonation.  If there are burrs there they will heat up and act like glow plugs.

In this photo you can faintly see the outline of where that casting ridge surrounding the intake valve was. 

I also took some time to clean up the valves a bit - I polished the front and back sides of them and also lapped the valve seats.  The exhaust valve took a good bit of work as the seat was pretty pitted from the temperatures it sees.  But You can see the freshly cut surface where the intake valve contacts the seat - should provide me with a good seal.  I filled the chamber briefly with water and didn't have any leaks, so I'm not expecting problems.  I will do a more thorough test when all cylinders are done to verify that all chamber volumes are close to each other and that I don't have any leaking valves.

One down, 7 to go.  Then on to the exhaust and intake ports.  I'm not expecting the others to take as long now that I have an idea of how to do it.