Hi Guys; New to model engine building and have a few questions . First off i just finished a hit & miss engine designed by Harold Depenbusch. The ignition parts came in today . My first question is on the hall sensor. Should i epoxey it to a plate in front of the magnet And where is the best location to mount the magnet? On the fly wheel or cam gear. My last question is, Will aluminum fly wheels work ok ? or do they have to be brass or casty iron. Thanks . By the way, grate web site.
Cast Iron would be a good choice. The heavier the better.
The hall sensor in my engine is just super glued in place. They stay very well but can still be removed if it needs to be replaced. They do fail from time to time so try not to get too carried away with mounting. Most fail from poor grounding. Make sure to have a good ground to the chassis of your engine.
Most hall sensors supplied with the ignitions are polarized. The north pole of the magnet has to face the sensor so test the ignition and mark the magnet with a sharpie marker before you install it. Ask me how i know!! Also, try to mount the magnet about .030 - .050 from the sensor. I shoot for .040 and have good luck with them.
I am not fimilar with that engine so maybe someone else can advise a good location for the sensor and magnet.
Thanks for the info. Probably won't get back to the engine until after the holidays. Will let you know how it turns out. As for the fly wheels, aluminum was the only material on hand at the time. Sure hate to make another set, am getting to excited to run the engine.
The magnet goes on the slow gear. Position the sensor for a spark a few degrees before TDC. The weight of the flywheel for a given diameter determines how much energy it stores. On a hit and miss that stored energy is the miss cycles.
Hi Dennis, I agree with Steve, just super glue it in place. I think Steve made a mistake on saying the north pole should face the sensor. I believe it's the south pole. In any case only one direction will work. gbritnell.
Dennis.....The weight of the flywheel has a great effect on how your engine will run.....If you need more weight on the flywheel, you can always turn a steel band and shrink (fasten) the band over your aluminum flywheel......The more weight the engine will run smoother, and you will have a slower running low end speed...Dale Detrich
Thanks for all the info guys. Started the engine the other day and it runs good. The aluminum fly wheels were to light, so i machined six 3/8 groves around the outside diameter and pored lead in and machined flat. they are a little light yet, but for my first one it runs good. started building another one. now that i know what i'm doing, i'll make this one real nice. thanks again.