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Great looking piston. I can read the word "balanced" in the finish of the piston in the last pic. Nice lathe work.

The way I currently plan to finish the valve seats and the best way to do it are probably not the same. In the past I have had good luck with a simple technique. I make the valve cage in one setup on the lathe, the last operation before parting it off is to set the cross slide to 45 degrees...

Peter, It is hard to realize how small this engine really is. Look back at the last batch of pictures Terry put up. In one he has a one/two/three block clamped to the work piece for vibration dampening. The one/two/three block looks huge next to the bell housing. I can't imagine getting...

It is so fun to have a home machine shop. You run into an issue, you design a few parts on the computer, go out to the workshop and make those parts, and viola, problem solved. I have a 3D printer and I like to print using HIP filament as support. That is, I use ABS for the main part, then...

Fokety, You already know this, but it is worth repeating. The beauty of the overhead cam engine is that there are no lifters, push rods and rockers to rob the engine of power; fewer parts to expand and contract with the heat, to wear, and to mess up the vavle lash. In my model engine, there is...

Beautiful as always Terry. How did you index the part when you flipped it over from the inside machining to the outside machining? Did you simply touch off the the edges of the squared off workpiece? Greg

Sorry, I misspoke. The tappets are made from 5/16" drill rod, the shank is turned down to 3/16" for a smooth fit in the tappet guide. I used a 1/8" ball end mill to make the pocket for the 1/8" push rods. Charles, what you describe about the size of the tappet head is very interesting...

Tappets Today I got back to making parts for the Wallaby, these are the tappets. They were a pretty straight forward lathe job, I used a 1/8" ball end mill to make the pocket for the 1/8" push rods. These are made from 5/16" drill rod, the shank is turned down to 3/16" for a smooth fit in the...

It is coming together really nice, and I think you did a steallar job on the spinner.

Crankcase Plans I am starting the process of creating the plans for each of the parts. The first few are going to be the most challenging. I am an engineer, not a draftsman, so I am learning as I go. On complex parts like the crankcase, the drawing is broken up into multiple pages and I am...

Thanks Terry, I will incorporate gasket thickness into my design. I see that you use a wide array of gasket types and thicknesses. Vinyl .003" ish, Teflon in.004", .010" and .020". It also seems that some flexibility during assembly is required as tolerance variation may required different...

I made a little display stand out of 1/8" aluminum.

Finalizing the Crankcase Today I worked on finalizing the crankcase which consisted of insuring the crankcase properly interfaces with all of the mating components. What this boils down to is making sure all the attachment holes match the mating components and that all the holes are accounted...

Oil Pump Assembly Today I worked on the oil pump assembly. I am using O-rings to seal the drive shaft and the oil passages in and out of the pump. For pressure regulation there are two grub screws that can be used to limit the passage width to both the top end and the bottom end. I do not...

Bob, I really like your suggestion for the fins on the bottom. I reduced the depth of the fins in the critical area, leaving them full depth where it does not matter. I am sure no one will know the difference, except maybe us. Regarding your comment on calling the engine an "Offenhauser...

Thanks for the kind words @johnmcc69. Peter, I am planning to have the magneto house the hall effect sensors to trigger ignition and the distributor for the spark plugs. I had not thought to make it an actual functioning magneto and have it power the ignition system. That is an interesting...

Magneto The Offy used a Bendix Aircraft Engine Magneto to fire the spark plugs. The engine did not require a battery as the magneto generated its own power. Today I research these and collected lots of good images. My current thinking is to make the magneto a project all by itself. It...

This is why I keep a can of ways oil near my lathe and use it liberally. just kidding ;-)

Oil Delivery System Today I worked on the oil delivery system, including the oil pump and the oil galleries required to deliver oil to top end (Camshafts) and to the crankshaft middle bearing. The engine will have a wet sump oil system, that is oil will be stored in the sump of the engine and...

Cambox Caps To make the cambox cap, start by imitating the shape of the top of the gear tower. There is a radius on the front and back of the caps, but they are different. The rear of the cap mounts flush with the cambox cover. The front however, has a raised lip and the edge has a larger...