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Rockerblock I.C.--Something a little different-

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  • #16
    I almost got caught. Look at the creative carving I had to do on the bottom of that water jacket to clear the revolving crankshaft.
    Brian Rupnow


    • #17
      The way the rocker allows the major parts to fold in on themselves and which led to the cam and valve arrangement I have to say that this is ending up looking anything BUT ungainly. It's actually turning into a seriously compact and natural sort of design.

      EDIT- You posted the cutaway while I was typing... OK, maybe a touch TOO compact!
      Chilliwack BC, Canada


      • #18
        Originally posted by brian Rupnow View Post
        One "fly in the ointment" on initial drawing Bri, you have your crank counterweight set up conventional,,, it needs to be 180 degree's reversed, it needs to be on the rod throw part of the business side, not a perfect solution because you will still get "block rock" but you will keep the two main forces in check and not cause them to hammer together at the same time in the same direction.

        on the bright side the rods basically cancel each other out so counterweights only need to be as much as piston weight...
        Last edited by A.K. Boomer; 04-07-2017, 03:06 PM.


        • #19
          I love where this is going. However, I would add a bit of height to eliminate that cut-out in the bottom of the water jacket. It just looks too thin....'

          1973 SB 10K .
          BenchMaster mill.


          • #20
            Pete--There is no pressure in the water reservoir. As long as it doesn`t cut thru and leak water, there isn`t any problem. Speaking of the water jacket, my plan for sealing the jacket to the o.d. of the cylinder is shown in this section view of the water jacket. An annular groove cut at each end, just slightly shallower than the cross sectional thickness of a .094 Viton o-ring. Hopefully an o-ring in each groove will seal any water leaks. I will be able to get two or three bolts thru from the flange on the cylinder into one end of the water jacket to keep it from turning on the cylinder.
            Brian Rupnow


            • #21
              A.K. Boomer--I have to think on that one about the counterweights a bit. When I built my opposed cylinder engine, I didnt use counterweights on the crankshaft, because the opposed cylinders balanced each other.
              Brian Rupnow


              • #22
                Well Hot-Dog!! I even managed to sneak an ignition cam and my old stand by Chrysler ignition points in behind the offside flywheel.
                Brian Rupnow


                • #23
                  There. That's a solid 8 hours playing. I have to dwell a bit on whether or not I have the crankshaft counterbalances on the correct side of the crankshaft or not, but other than that and a gas tank, the engine design/modelling is finished. Now I have to go shovel out the end of the driveway. We got 5" of April Fools last night. Yuk!! I was hoping we were done with that white stuff!!
                  Brian Rupnow


                  • #24
                    That's fast work by anyone's standards esp. when you consider your engineering it all on the fly.

                    I think this engines going to be fun to watch run with the main rocker exposed like that.


                    • #25
                      Some shallow vertical finning on the jacket would look pretty cool and increase the surface area to the air. Not traditional I know.....
                      Chilliwack BC, Canada


                      • #26
                        Originally posted by lakeside53 View Post
                        how about a wankel?
                        I always thought it would be cool to build an engine based off of one of those pump tops - like those old drills with the spiral shaft that can be made continuous at the end of its stroke to work the main unit back the other direction,

                        you would end up with incredible ratio of flywheel revolutions for every power stroke, would be dead simple except for the valve actuation although im sure something could be done if thought about it...
                        you would not even need a pivot at the pistons end, you actually might end up with an engine that can run at extremely low stroke exchange - even though the flywheel would still be cranking out quite a few RPM's

                        would be interesting to see what would happen.


                        • #27
                          Taking your points backwards:

                          "...drastically altering the compression stroke piston speed in comparison to the power stroke piston speed...". What is the potential advantage here? And what would you want? Faster compression and slower power stroke or the opposite? And WHY?????

                          " no longer have to put the piston skirts through the radical loading that's accompanied by the crank angles...". Just what are the piston skirts? How are they "radically loaded in other designs? And just how does this design decrease this radical loading?

                          Finally, I took AK's remark differently. I thought he meant that parts that were oscillating in opposite directions helped the balance. So they weren't just nice to look at, but functional. Hence, the two connecting links in this design could be in almost perfect balance both left-right and up-down.

                          I guess my main question is just how is this design an improvement over the standard piston-link-crankshaft design? You got some splaining to do, Lucy.

                          Originally posted by A.K. Boomer View Post
                          It's cool - no reason in the world it should not work and I agree with BC when it comes to hobby engines the more extravagant links to get the job done the better...

                          This engine does have a unique advantage over a standard piston engine Brian,,, you no longer have to put the piston skirts through the radical loading that's accompanied by the crank angles,,,

                          You also have the option of drastically altering the compression stroke piston speed in comparison to the power stroke piston speed, could be something fun to play with...
                          Paul A.
                          SE Texas

                          Make it fit.
                          You can't win and there is a penalty for trying!


                          • #28
                            I always think it sucks to design a nicely proportioned engine, and then stick a gas tank on it. Gas tanks don't leave you with a whole lot of options. They have to be near the carburetor, they have to set below the carburetor throat (but not too far below), they shouldn't block any other equipment which needs frequent adjusting, and they shouldn't be directly in line with the exhaust. That being said, you just do the best you can and hope it doesn't ugly things up too much. This is not an improvement over the normally configured gas engine. It's just a different, artsy fartsy way of doing it.
                            Brian Rupnow


                            • #29
                              You're right the gas tank really does take away a lot.

                              An alternative would be a small pump driven by a cam lobe and a small supply bowl as part of the carb or just beside it. Instead of a float use a return line that is a bit larger than the pump feed line with the level of the return at the desired fuel height. That way you can get away with something no larger than a thimble. And perhaps even smaller. The pump doesn't need to be a high volume as long as it can move a touch more than the engine needs when running under a load. The supply bowl would also need a small vent hole to atmosphere in the top. In fact using a metal thimble with the K&S brass lines soldered to it would make a really cool looking supply bowl if it were right on the carb.

                              That way you can have a flat tank inside the wood base. And you'd be able to see the rocker arms and valves far more clearly.
                              Chilliwack BC, Canada


                              • #30

                                Suggest that you rotate the exhaust pipe /muffler to vertical.