dual sensor starting ignition
02-09-2005, 03:51 PM
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dual sensor starting ignition
Zagnut mention this sometime ago and I hope this is a correct visualization. It has raised a couple of questions that you guys may clarify.
1) does it make any difference if the switch is a make-before-break type or will a break before make switch work okay? Don't want to damage the ignition module.
2) any thoughts on at what degree the starting sensor should be set BTDC?
3) which of the sensor leads on a CH Ignition would you switch? Dave mentioned he switched only the output lead that goes to the SCR. (What is SCR?) Would this be best method for a CH Ign?
The original thread: http://www.rcuniverse.com/forum/m_16...1/key_/tm.htm#
Will post new improved pic shortly.
1) does it make any difference if the switch is a make-before-break type or will a break before make switch work okay? Don't want to damage the ignition module.
2) any thoughts on at what degree the starting sensor should be set BTDC?
3) which of the sensor leads on a CH Ignition would you switch? Dave mentioned he switched only the output lead that goes to the SCR. (What is SCR?) Would this be best method for a CH Ign?
The original thread: http://www.rcuniverse.com/forum/m_16...1/key_/tm.htm#
Will post new improved pic shortly.
02-09-2005, 04:06 PM
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RE: dual sensor starting ignition
Any thoughts on using a HD battery switch and switching two of the leads to the sensor? Cut off the connectors and soder into circuit.
02-09-2005, 05:20 PM
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RE: dual sensor starting ignition
Sounds like a big violation of the K I S S principle...
Any small engine does not need variable timing...28 BTDC works just fine...
I set all my G26 conversions up with fixed timing, no complaints so far....
Small engines under 3 cubic inches don't kick back hard enough to hurt anything if you flip the prop with AUTHORITY.....
Any small engine does not need variable timing...28 BTDC works just fine...
I set all my G26 conversions up with fixed timing, no complaints so far....
Small engines under 3 cubic inches don't kick back hard enough to hurt anything if you flip the prop with AUTHORITY.....
02-09-2005, 05:51 PM
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RE: dual sensor starting ignition
Because I'm using ignitions with adjustable advance there is no need of 2 sensors, I set the maximum advance at full throttle and a smooth curve is automatically calculated for the entire rpm range, the advance is applied gradually without jumps or switching between 10 and 28 or so. I just use 1 sensor at 35/40 BTDC, the first spark is retarded by the ignition so it does not kick back and the start is easy even on big engines.
02-09-2005, 08:55 PM
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RE: dual sensor starting ignition
On a CH ignition you would switch the white wire on the sensors.
Some choices, Big start/run switch to be flipped after starting.
Micro switch hooked to throttle, at some point above idle the run sensor is turned on. Disadavantage to this is a big change in RPM as you blip the throttle trying to land.
Some choices, Big start/run switch to be flipped after starting.
Micro switch hooked to throttle, at some point above idle the run sensor is turned on. Disadavantage to this is a big change in RPM as you blip the throttle trying to land.
