Not-a-number

It took several days to figure out how to machine the bowl/chamber. Was a challenge for sure, both in the programming and the surface finish. But it has come out nicer than I thought it could considering how long and chattery the tool could be. Ive talked to the engine machine shop that I will have hone it and it seems like it might be a good idea to have them finish bore it anyway. Then itll be done in a proper boring machine with proper tool by someone who knows what theyre doing. So Ill leave about 0.1mm on the bore but finish the rest.

Have completed the sparkplug cup area. Theres a cup that presses over the top of the dome and orings to the top of the block. Usually its a press fit and bonded on but I think Im going to Oring top and bottom and retain it differently. Just so I can take them out. Now starting on the bores. Roughing them with a long facemill and then with a boring head. You can get some pretty nice tooling on AliExpress for a couple hundred bux these days!

Been working on the 2 cylinder to work out the programming/process. Learning a lot. For the most part its rigid enough to get a good surface finish, but a couple of faces want to ring no matter what. Luckily a couple of jacking screws sorted it. It may or may not be a problem on the full block but if it is its not a big deal. Unless I forget to remove them before the 4th axis moves!! Now onto the harder part of boring and doing the combustion chamber. Boring should be ok but doing the bowl will be tricky. Waiting on a special tool holder for it.

The large plate moved around quite a lot due to how much material was swarfed. So iv spent a lot of time measuring all over and cleaning it up to get it accurate. Measured and clocked it up once assembled and all looks good now. Definitely looks serious!

Making a ton of swarf on the main saddle plate. Have one more plate to go.

There is ‘mostly’ a lot of machine allowance. But the ports have no allowance. So they will be where I need to datum in a way. I’ll start off by setting up out of the 4th axis trunnion and machine the face that mates to the crank case. That height will depend on the port positions and primarily the valve seat position. There’s not a lot of play there and it’s a hard thing to get to to check if it’s going to have allowance. Then when it’s in the trunnion it would just be determining port/valve positions along the length. It’s going to take a lot of measuring before starting.

Completed the main tailstock end. Onto the final long plate now. Its working out well. I have a Renishaw probe on the mill thats a game changer for datum setup and tool height setting. Really accurate. Not like the good old days when I used a wobbler and a cigarette paper borrowed from a work mate!!

Started on a 4th Axis Trunnion for the cylinder block (and other things later) All the plates are dowelled so hopefully later it can be a bit modular with switching out plates. The tail stock bearing is a Nissan Tiida wheel bearing. Dont see why that shouldnt work but we'll find out how ridged it is soon! Firstly I did a mounting plate for the 4th axis to shift it off the table ~150mm to get more room.

Acquired a pair of Zenith carb castings off a guy in the Netherlands. He finished his 59 a few years ago and had these left over.

Got 2 great sump castings and a 3rd with a small defect that would be fine once welded.

Looks like its come out great! They will do another one and Ill pick them up next week. Next up I think Im going to machine the blocks. Need to make a big trunnion for the 4th axis!

All boxed up at the foundry and moulds filled. They added their expertise with risers and runner system. See how it goes in the next couple of days.

Added the base/surround plates to them. Doesnt look like much but they need to be very flat as they are the datum face for the core. So if either side is bowed itll lift the core up higher than it should. Bonded a couple together on a surfaced table but even then it bowed afterwards. So they are now mounted to some box section. Now they are completed! Happy with how they turned out. Ill be taking them up to the foundry next week to try them out!

Sump inner and outer patterns basically finished. The interlocking/keyway loose pieces seem to fit quite well. We'll see if they come out of the sand ok! If they do then the entire sump mould assembly will only be 2 pieces of sand (though about 80kg a piece!) Outer Mould Pattern Inner Mould Pattern

Inner core patterns designed and all printed. Now to bog and paint them! It takes a lot of finishing!