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Old 09-20-2013, 05:37 PM
Flyin' Around
United States, SD, Vermillion
Joined Jan 2006
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EVOLUTION 58 GX2 timing ???

I have a new Evo 58cc GX2 putting it in a Pitts 50cc. Installed the engine and setting up prop position for starting and noticed there are two magnets on the hub. One is about 10 deg before TDC and the other is about 50 degree after TDC. Anyone know the reason, or purpose.
phil
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Old 09-21-2013, 10:37 AM
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Joined Nov 2009
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Pe Reivers was the expert on these engines and unfortunately he is no longer with us to answer your question. I can tell you a little about the two magnets but my answer will pale in comparison to whatever knowlege Pe could have gave you.

All I can tell you is what little I know about my engine and valec ignition, which was a early mvvs/evolution ignition. It also has 2 magnets on the hub, these magnets are polarised, on north one south. The ignition there for knows which magnet is which when they pass the sensor.

I can only presume this refines the timing angles a buit better by having a much more precise idea of how the motor is running?. Pe also stated at one time that one magnet "resets the ignition so a spark will be produced as it then passes the next magnet" And perhaps has other safety features like possibly prevent a spark from being produced if the first turn of the motor is to slow, or the wrong way? I know my ignition will not spark if left on for to long a period of time as a safety feature. And I know on some of the later version ignitions will auto shut down if it sences reverse running, my earlier version does not have this feature.

Hopefully others can give some info as I also would like to be educated a bit more on the advantages of two magnets.
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Last edited by raydar; 09-22-2013 at 10:23 AM.
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Old 09-21-2013, 10:43 AM
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Super08's Avatar
Fort McMurray AB
Joined Mar 2008
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Just set the prop to the position you wish with the engine coming up on compression. As for the use of two magnets if I recall it monitors RPM by how long it takes between the first and second magnet to pass the sensor. Then the ignition unit then knows how much timing to use.
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Old 09-21-2013, 10:52 AM
Who put that tree there?
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Fort McMurray AB
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Yes if Pe was still with us he could answer with specifics and you could take each and every word as gospel.. He knew every detail there was to know about the MVVS line.
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Old 09-21-2013, 03:56 PM
Flyin' Around
United States, SD, Vermillion
Joined Jan 2006
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evo 58

thanks guys for the response, I think your all right. Sure wish Pe was still around. Anyway reading the instructions of the ignition, it does shut-down on reverse running, also no activity for 1 1/2 minute, also senses something with the rpm. So what you all have said seems to be the reason for the two magnets, thanks a lot.
phil
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Old 09-21-2013, 10:54 PM
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Australia, VIC, Sale
Joined May 2008
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OK - in Laymans Terms.
(This is an extract of information given in a long discussion I had off line with Pe about ignitions in general)

The two magnets serve a few major purposes.
1 - to give an accurate indication of the engine RPM
2 - To determine the direction the engine is running (so the ignition will automatically shut off if it is running the wrong direction)
3 - to "Reset" the ignition to allow a better dwell period for the next spark to build up.

One magnet is North Pole, the other is South Pole. If you are installing an ignition that doesn't require the second magnet - simply set the sensor up to the magnet that makes it fire. If it is a sensor like the RCExcel uses - you can turn the sensor itself over to make it fire on either of the magnets (but not both).
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Old 09-21-2013, 10:58 PM
Who put that tree there?
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Fort McMurray AB
Joined Mar 2008
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That is what I did to my friends 58. Runs like a charm on the Rcexl ignition and seems to start better as well. I had to make a little custom bracket to hold the hall sensor for the correct timing using the same two bolt holes from the factory sensor.
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Old 09-21-2013, 11:25 PM
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I filed the hub lugs down on mine and used one of Miltons Universal clamps to mount the sensor.

Pe used a cable tie on his 116 - it worked well but it just didn't look right to me LOL
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Old 09-22-2013, 08:32 AM
Doo It! Doo It!
Grapevine, Texas USA
Joined Oct 2009
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I went with a CH-Ignitions setup on my Evolution 58cc engine. CH-Ignitions makes a nice aluminum timing sensor holder for the engines. The engine runs great with it all too. The static timing was set to 30 degrees BTDC.
ref http://www.flyinggiants.com/forums/s...ad.php?t=83169
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Last edited by earlwb; 09-22-2013 at 08:34 AM. Reason: add more info
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Old 09-22-2013, 09:14 AM
Who put that tree there?
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That is a very nice bracket CH has made up.
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