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| Another version of how not to build a model engine |
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| sorveltaja:
My previous post's problem was caused indeed by the temporary breaker points, that I made :wack:. As I looked back the replies, there was good suggestions, such as using TIM4, or piezo igniter. 5bears's TIM4 has the Hall IC, HAL506UA, that has became obsolete. Nowadays it seems to be a 'hard to find' -part. Couldn't find the replacement either :scratch:. The piezo ignition is ruled out, because it requires far too much force to make a spark. With bigger engines, that have the grunt, it wouldn't be any problem though. What's left, is to fit an automotive points to the engine: |
| sorveltaja:
Dark piece in the middle is roughly cut piece of 1.5mm mild steel. Here with holes to attach the contact breaker. Aluminum part is for tightening the assembly to crankcase backplate: ...and yes it fits!! ::): The steel plate has some excess material in it, so after before cropping, it looks like this: |
| NickG:
S, Looking good, what sort of cam are you going to use? I know the webster engine uses car points and he just has a cylinder of metal with a flat milled on it - seems to work well. Nick |
| sorveltaja:
Nick, I was going to make a roller for ignition cam, but it would have been too complex. Simpler the better :beer:. Brass was used for the cam, and polished it a bit: |
| sorveltaja:
Addition: After previous testing, that was made using ethanol, the engine had couple days of rest. When it was time to fit the breaker points to it, I noticed that the crankshaft was really stiff to rotate. So I sprayed some wd-40 from spark plug hole, and gave it spinning. Stiffness was gone. I should have done that right after testing. That problem never occurred after using pure gasoline... Correct me if I'm wrong, but ethanol, if I dare to say, is water based liquid :scratch:. If even small amount of it is left inside the engine, rust and corrosion is to be expected :wack:. |
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