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| AcieraF3:
I have almost finished building an Elmers 25 wobbler engine. The only thing I need to do is drilling the port hole in the cylinder. I was triggered by this discussion in Spuddevans project report: Now, I went back and looked at your cylinder with the pivot in it. Are you going to forget to drill the entery hole for the air into the cylinder? :poke: Just wondering. :) Well spotted!! Actually I deliberately have not drilled it yet. I figure on assembling the whole gether, positioning the crank so that the cylinder is in the right position for the exhaust hole in the frame to line up with where the inlet hole is meant to be on the cylinder, and then spotting through to accurately mark up the postion. Does that make any sense outside of my head? Tim My question is: what is the position of the crank so that the cylinder is in the right position for the exhaust hole. A sketch would be very helpful. thanks all :Doh: |
| spuddevans:
--- Quote from: AcieraF3 on November 16, 2011, 06:48:48 PM ---My question is: what is the position of the crank so that the cylinder is in the right position for the exhaust hole. A sketch would be very helpful. --- End quote --- Hi there AcieraF3 :wave: I'm not sure if what I did was the correct way, but it worked for me. What I did was to assemble the engine, and position the crank with the crankpin at the very top of its rotation. That will position the cylinder at the right angle. Then I just made a little mark with a drill held in a cordless drill, guided by the exhaust hole in the frame. Then I dissasembled it and then drilled the inlet/outlet hole in the cylinder on the mill. It may not have been the proper way, but it worked for me. Let us know how you get on, even better, take some pictures and show us :worthless: :D Tim |
| Stilldrillin:
The correct position of the crank for alignment, is at 70*. Not the 90* that most engines are drilled at....... :scratch: This gives an overlap of the holes, allowing longer opening time of the port. :thumbup: David D |
| AcieraF3:
--- Quote from: Stilldrillin on November 17, 2011, 08:19:26 AM ---The correct position of the crank for alignment, is at 70*. Not the 90* that most engines are drilled at....... :scratch: This gives an overlap of the holes, allowing longer opening time of the port. :thumbup: David D --- End quote --- David, what do you mean exactly by 70 degrees. A small sketch would be very helpful. :Doh: thanks |
| Stilldrillin:
--- Quote from: AcieraF3 on November 17, 2011, 02:38:17 PM --- --- Quote from: Stilldrillin on November 17, 2011, 08:19:26 AM ---The correct position of the crank for alignment, is at 70*. Not the 90* that most engines are drilled at....... :scratch: This gives an overlap of the holes, allowing longer opening time of the port. :thumbup: David D --- End quote --- David, what do you mean exactly by 70 degrees. A small sketch would be very helpful. :Doh: thanks --- End quote --- Ace. I really hoped you wouldn't say that! :palm: Please excuse the 'orribly horrible scribble........ Drilling the valve plate at the 70 degree position, allows the cylinder port to slightly pass, (but not close) the valve port, before returning. Giving a longer opening time..... :thumbup: Hope this makes sense! :scratch: David D |
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