1" Bore x 1" Stroke Vertical i.c. Engine

[Brian Rupnow]

Hi Everyone---Hope your new year is going well, so far. I fell on the ice in my driveway just after Christmas and hurt my back. Between the pain from that, and my arthritis (which is exceptionally bad this year), I've had a very quiet January. Finally, today, out of boredom I sat down at my computer and started importing files from previous engines to see what would be involved in another i.c. engine. I have never built an engine before with a vertically split crank-case, so after looking at some really lovely examples on the forums, I've started putting things together on cad. I enjoy a quiet day designing, and this is what has turned up so far. Nothing really new or exciting here, but I like to see an engine coming together. I have no cnc here, just manual machinery, so that's what my engine will be based on, build-wise.---Brian

 

[johnmcc69]

Looking forward to seeing it come together Brian!

John

 

[ShopShoe]

Brian,

So sorry to hear about your back. I hope it gets better.

Meanwhile, I'll be following your new design.

--ShopShoe

 

[Brian Rupnow]

I spent this morning sussing out the cylinder head and the valve train. It looks good to me right now, so I'll go eat some lunch and then see if it still pleases me when I come back this afternoon.

 

[Eccentric]

I am liking it Brian. I like the parallel cam shaft/crankshaft layout. Will you use aluminum cyclinder and head with a cast iron liner? Or solid cast iron cylinder? Is the stroke also going to be an 1"?, will this be on the higher compression side then? Sorry about your slip, and I understand about the arthritis, my fingers really flare up when it gets cold.

 

[petertha]

One suggestion I would make is: mill a flat on the head where the inlet/exhaust ports enter so that your pipe can be flanged & bolted to the head. My radial has counterbores with internal threads. They require threaded nuts, up-turned or trumpeted ends on the tubing & some kind of internal seal ring or washer (capable of temp on exhaust). And there typically isn't a lot of meat in the head for internal threads anyways. A flanged pipe & gasket eliminates a lot of these fiddle-fart issues.

 

[Brian Rupnow]

Most of the work today was centered around the cylinder head. The carb shown is a Traxxas 4033, and the valves are 1/8" stem diameter with a 3/8" head. The exhaust is identical to what I used on the vertical hit and miss engine last year, and I'm thinking I may pack it with steel wool to see what effect that has on the sound.

 

[Brian Rupnow]

My life is a lot simpler when I make the cylinder from solid grey cast iron. I could do an aluminum cylinder with an cast iron liner, but all that does is complicate things, and the heat dissipation is never as good. Petertha--I've never had an issue with threaded ports in the cylinder head for the carb adapter and exhaust to screw into. I could make flanged connections as you suggest, but that just makes more work. I find that a dab of 638 Loctite keeps things from coming unscrewed, but it can still be disassembled with wrench if I need to.

 

[Brian Rupnow]

This engine will have the timing gears on the outside of the case. They will get their own polished brass??? cover. I haven't mounted the ignition points yet, but will probably set them up to be between the crankcase and the flywheel.

 

[Brian Rupnow]

That's enough silliness for one day. Tomorrow I'll figure out a mounting plate for the ignition points and a gas tank.

 

[awake]

Looking good, Brian. Are you planning on using a wet sump / splash lubrication? I guess you'll need a vent for the crankcase - ? (I am asking out of ignorance, not as a veiled suggestion!)

 

[Brian Rupnow]

Yes, it will be a wet sump. The design is not complete yet.

 

[Brian Rupnow]

So, here we have it at 99% designed. An interesting little engine, with maybe a few shiny brass (gold??) parts just to set off the iron and aluminum cylinder and crank case. The crankshaft and the camshaft ride on sealed ball bearings, and the cams are inside the crankcase to guarantee splash oiling from the wet sump. For a little bit of added "pretty", I've designed a rather swoopy gas tank support.---After designing and building about a dozen of this type of engine, everything begins to look the same. I will run a Viton piston ring on this engine. Any comments are welcome.

 

[Brian Rupnow]

In this view of the engine, I have hidden the flywheel so you can see the plate which the ignition points are attached to. That plate has a split in it and rotates on a boss attached to the crank case. By unscrewing the blue handle the plate can be turned clockwise or counterclockwise, giving the ability to dynamically advance or ****** the ignition while the engine is running. the drawing shows overall sizes.

 

[CFLBob]

At last an engine where I can figure out the cubic inches of displacement in my head!

Are you conceptually done? There's no RPM control here. I'm leaning toward my next build being a hit and miss., as I find that interesting.

BTW, good to hear you're recovering from the fall. I can joke about it, but falls on ice can be as serious as it gets.

 

[Jasonb]

The Traxxas carb Brian shows has a throttle on it to adjust speed, timing will also have a big effect on rpm.

Looks like Brian has drawn heavily on the 1936 Midget design for this one and that actually just had a straight through venturi on it so all out or nothing. I made a carb for mine with a throttle barrel.

 

[Brian Rupnow]

Jason---You're right. The 1936 Midget was my inspiration for this engine. Bob, I highly recommend the Kerzel horizontal hit and miss. It is a great little engine, and uses a lot of the skills you have honed on the Webster. A word of warning though---don't use a Viton ring on the Kerzel. If you do you'll get great compression but really poor coasting cycles because of the drag.
https://www.homemodelenginemachinist.com/threads/brian-builds-the-kerzel-hit-and-miss-i-c.10091/

 

[Ghosty]

Brian,
This one looks good, will be watching this.
Andrew

 

[Jasonb]

Brian, are you going to be using a lost spark? I see you have your points on the crankshaft so will be getting a spark every turn of the crank rather than every other turn that is more usual for a 4-stroke.

 

[Brian Rupnow]

Jason---I always mount the points to run off the crankshaft, so yes, it is a wasted spark system. Doing it this way gives you a lot more room to mount the points.