Horizontal Air Cooled Engine

[Brian Rupnow]

I had a stroke of good luck this morning. After tapping something like 20 holes, and assembling things, I discovered a length of 01 steel with two cams cut on it. The last time I set up to cut cams I decided to cut over-length while I was in the set-up for use on a potential future engine. The future has arrived!!!

[mikehinz]

Brian, I very much like the look of this engine!  I'll be following along closely!

Mike

[Brian Rupnow]

Thanks Mike.---I picked up my cast iron today to make the cylinder. The only material that my supplier had in stock was 2.1" diameter ($25 for 4"). I haven't made the cylinder yet, but this gave me an idea. Without changing anything, I can make it look like this if I want to. This shape harkens back to some of the early model two cycle airplane engines that were made in the 1930's to 1950's. I kind of like it.

[mikehinz]

Brian, that's an interesting shape for the cylinder!  Very retro looking.

BTW, what's the bore and stroke of this engine?  I didn't see it your previous posts?  And as a bonus what's your valve steam and head dimensions?

Thanks!

Mike

[Brian Rupnow]

This engine is 7/8" bore x 1.25" stroke. The valve stems are 1/8" diameter and the head of the valve is 3/8" diameter.

[Art K]

Brian,
I like the progression, improving on an earlier design, seeing the faults/problems & correcting them. Looks good!
Art

[Brian Rupnow]

Hi Art--Hope you are doing well!! Are you building anything these days?---Brian

[Brian Rupnow]

This morning I made up the main baseplate. This plate has an interesting feature in it. In order to keep everything small, a scallop was cut from the baseplate to clear the 40 tooth cam gear.

[Brian Rupnow]

This afternoon I machined a cast iron cylinder. I like that shape a lot. I've got a temporary clamp on there right now, because I haven't drilled any bolt holes yet. I'll do that tomorrow.

[Brian Rupnow]

Since I have to build a complete cylinder head, I may as well get crazy and make a finned cylinder head. It isn't a lot more work to do this. It just means the overall height of the cylinder head increases by 1/4". The valves get 1/4" longer, and the blue rocker arm support gets 1/4" taller, and the pushrods get 1/4" longer.

[Brian Rupnow]

Today I drilled clearance holes in the cylinder base flange and drilled and tapped holes in the other end of the cylinder, and attached the cylinder to the frame. I really suffered getting the cylinder bolted to the chassis, and I'm going to change the design drawings of this to give a bit more wrench clearance. I also made the fan housing and installed it. I'm not really sure of how the finished fan and bearings are going to be attached, but for now I will just call it a work in progress.

[Art K]

Brian,
You are making good progress. I like the addition of cooling fins to the head. I'm sure it will run much cooler. I am doing well, staying healthy although I've lost some elderly church friends to Covid. I also have been busy at work, 50 hour weeks since a year ago January. I have been slowly progressing on a mill enclosure but that is about all I'm getting done in the shop. We sold my parents house this summer so that consumed a lot of time and energy both mental and physical. I did get plans for George's flat head V8 and have begun cad on the bell housing. This is taxing my skill level in cad.
Art

[Brian Rupnow]

This cylinder head is a complex little guy to machine. None of the individual steps are difficult by themselves, but the hard part is having something to hold onto while you do them.---And if you don't do things in the correct sequence, you can easily "paint yourself into a corner". I do have a plan, and the first part of my plan is using my four jawed chuck in the lathe to turn a "stem" to hold onto with the chuck mounted on my rotary table for all of the following steps.

[Brian Rupnow]

There is a lot of work to this cylinder head, and I am only about half done with it. However, it's a beautiful day here, sunny and 64 degrees F, so I'm going to put my tools away and take my good wife somewhere for lunch. This is probably one of the nicer days that November will offer, before we have snow up to our armpits. The slots were cut with a slitting saw.

[Brian Rupnow]

So here we have most of a days work. I took good wife out for lunch, then came back and started laying out, drilling, and tapping holes and the main 1" counterbore in the cylinder head. So far, so good. I am rather amazed at how small this thing is. That's a standard size pocket calculator laying in the foreground to give you some ides of a size comparison.