Flat head hit and miss engine???

[Brian Rupnow]

Does anybody have information on a flat head hit and miss engine? I don't think I have ever seen one. Maybe they never existed. I am looking for a different type of i.c. engine to build. I have built many overhead valve hit and miss engines, side shaft hit and miss engines, horizontal engines, vertical engines, tee head engines, angle head engines, one two cycle engine, Atkinson engines, flame licker engines, sterling cycle engines, opposed piston engines, oscillating cylinder engines, and one flathead conventional engine. I woke up this morning thinking about flat-head hit and miss engines, and I don't ever remember seeing one.---Brian

[Jasonb]

I suppose you could class a lot of the vertical hopper cooled engines like the Baker Monitors and FM Eclispe as flat head as they have the valve stems facing down though often into a separate "valve chamber" at the side rather than the top of the crankcase.

[Brian Rupnow]

Jason--You certainly do some beautiful work. What is the purpose of the ball on top of the cylinder on the red engine? Does it just hold cooling water for the cylinder head?

[Brian Rupnow]

Here is an interesting video of a Briggs and Stratton reconfigured to be a hit and miss engine, but the hit and miss is controlling only the ignition. This is not a true hit and miss engine, more of a "Make and break" engine such as used for Dorys on the east coast in the 1940's.

<a href="https://www.youtube.com/watch?v=Z9SsaJrXEDA" target="_blank">http://www.youtube.com/watch?v=Z9SsaJrXEDA</a>

[Jasonb]

Yes, same with the others the Eclipse is probably the closest you would get to a "flat head" if you ignore the hopper part of the casting

As does the smaller VJ Monitor, socket for the tapered valve cage being machined

[Brian Rupnow]

Here is a video much closer to what I have in mind. There is a set of centrifugal governors tucked in behind the flywheel that are moving a lever which locks out the exhaust valve and holds it open during the "miss" cycles. Although this engine still utilizes the original camshaft to open the intake valve, the intake could be atmospheric, so that no intake cam would be needed.

<a href="https://www.youtube.com/watch?v=heh0ci7DEFk" target="_blank">http://www.youtube.com/watch?v=heh0ci7DEFk</a>

[Jo]

Why don't you design yourself one from scratch Brian, that way it will be exactly what you desire

Jo

[Brian Rupnow]

Jo, I don't have any trouble designing something from scratch. That's what I do. Sometimes though, it's coming up with the idea of what I actually want to design that puzzles me. I thought of this idea last night while laying in bed. Almost 99% of the ideas I have, have been designed or built before. A web search generally turns up something close to what I have been thinking of. If I ever had a truly original idea, I'd be living on a south sea island with last years Playboy playmate eating pineapples.---Brian

[Art K]

Brian,
I look forward to see what you come up with. It should be a fascinating project! BTW if you're interested in a care package of files I inherited more than I will ever use.
Art

[Brian Rupnow]

Art---Good to hear from you. I'm okay for files now, I just laid down $102 yesterday for six new files.

[Brian Rupnow]

All Right!!!--Making this up as I go along. I'm going to design (and maybe build) a model flat head hit and miss engine. I have so many models of so many engines now, that I seldom start from scratch. My software lets me borrow any part from any previous engine and save it in a new file. As long as I rename the part when I save it to a new file, any changes to it will not affect the original model. I have borrowed heavily from my last horizontal hit and miss engine, because a lot of the parts can be re-used with no changes. Some of the parts will change, but any changes made in this new file won't affect the original files from which the part was borrowed.

[Brian Rupnow]

Yoweee---Do I know what I'm doing???--Not a bit. But I've got the morning in anyways---

[Brian Rupnow]

Hah!!!--Knew I could do it. The secret is all in the manifold block that attaches to the side of the cylinder. Intake valve stem faces up and is atmospherically actuated. Exhaust valve stem faces down and will be operated by exhaust cam or held open by hit and miss device.

[Brian Rupnow]

Okay, after some serious layout and shortening my con rod by 2", it appears that to have really effective cooling I will need the flywheel outer diameter to be made from a piece of 8" nominal schedule 40 pipe. I can probably cheat a bit and use a piece of 7" o.d. heavy wall tube. that depends on what my supplier has in stock.

[Jasonb]

If you narrowed down that pale blue valve block you would have more of the fins clear and in the airflow, as it is that blocks quite a few fins. Fins along the top of the head would also aid cooling.

Do either the exhaust pipe or carb actually need to be turned through 90deg, you could just put them at the end of the block where you have for passage drilling blanked off.

Inlet valve could also face downwards more like a "Flathead" Briggs rather than copy the Monitor's layout

Also interested to see how your valves work and what internal passages there are in the block