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Flat head hit and miss engine???

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  • Flat head hit and miss engine???

    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
    Brian Rupnow
    Design engineer
    Barrie, Ontario, Canada

  • #2
    A little explanation of how the Hit and Miss Engine operates and functions, with a little help from SmallEngineMechanic Mike.Check out Mikes channel at http:...

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    • #3
      Thanks Dunc---All of those engines are overhead valve types, not flat heads.---Brian
      Brian Rupnow
      Design engineer
      Barrie, Ontario, Canada

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      • #4
        Could adapt something like this?
         
        Helder Ferreira
        Setubal, Portugal

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        • #5
          I can see why they maybe don't have flat head hit and miss engines. With the flat head you have the cam shaft with a lifter riding on it and the valve is operated directly by the lifter. No room for any type of hit and miss mechanism.
          Larry - west coast of Canada

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          • #6
            Noitoen--That video was great. That is what I want to design and build. Wish I had some more information about it.---Brian
            Brian Rupnow
            Design engineer
            Barrie, Ontario, Canada

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            • #7
              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.

              Here is a video of a worn out Briggs Model 9 that I converted to Hit and Miss!Hit and Miss Engine Tutorial by 805RoadKing:https://www.youtube.com/watch?v=YUE...

              Brian Rupnow
              Design engineer
              Barrie, Ontario, Canada

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              • #8
                Thinking more about this while eating my breakfast. If you were to design and engine with a relatively long stroke to give as much distance as possible from the crankshaft to the head, then make the valves as short as possible with reasonably short valve guides and mount the cam shaft as low as possible in the engine, it would give you room for much longer valve guides. this would give you the room to come up with the latch mechanism to create the hit and miss engine. It would take a bit of head scratching to come up with a design for the lifter and latch mechanism but you have the equipment and knowledge to work that out.
                Larry - west coast of Canada

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                • #9
                  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.

                  8 horse Briggs & Stratton converted into a hit and miss

                  Brian Rupnow
                  Design engineer
                  Barrie, Ontario, Canada

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                  • #10
                    OK, you can throw my idea out. The orange colored Briggs is a smart idea. I noticed they appear to have a different valve retainer on the exhaust valve. You would have make sure the retainer was secured to the valve stem somehow or the valve could drop down and possibly release the conventional type of retainer.
                    Larry - west coast of Canada

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                    • #11
                      Check out Minneapolis Moline R and Z tractor engines for an unusual design. Heads on the side, manifolds on top. The valves come in from the side. One end of the rocker rides on the cam the other on the valve. I bet a smart guy like you could integrate a lockout mechanism on the exhaust valve without too much trouble

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                      • #12
                        The standard hit and miss has the centrifugal setup engaging "the" valve (exhaust). Intake is "atmospheric" (valve with spring).

                        Can be "wasted spark", or combine the ignition trip with the valve.

                        I see no reason that flat head would be much different from a standard type. Usually the pushrod on overhead valve just operates a lever anyway, so it could just as well operate a valve directly.

                        Should be a fun project.
                        CNC machines only go through the motions.

                        Ideas expressed may be mine, or from anyone else in the universe.
                        Not responsible for clerical errors. Or those made by lay people either.
                        Number formats and units may be chosen at random depending on what day it is.
                        I reserve the right to use a number system with any integer base without prior notice.
                        Generalizations are understood to be "often" true, but not true in every case.

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                        • #13
                          Someone, please explain why an engine is designed to be hit and miss.

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                          • #14
                            Wasn't it originally to control the speed?
                            Helder Ferreira
                            Setubal, Portugal

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                            • #15
                              Yes, originally and still. It serves no other purpose

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