Author Topic: EW magneto timing adjustment  (Read 3158 times)

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Offline geomellish

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EW magneto timing adjustment
« on: 30 Mar 2016 at 11:00 »
I need to re-time the EIC magneto to my EW350.  The magneto engages with the engine on two 90 degree dog ears. It seems to me that the only way to alter the timing of the magneto to the engine is to rotate these dog ears to an appropriate position on the magneto then fix them in place onto the cone shape drive using a small central bolt. Please see photos.

The magneto cone drive has a hole for a key/lug (missing), the dog eared piece has a slot for a key.  If I replaced the key the timing would be about 150 degrees out and in any event I can't see any method of adjusting the timing if the dog ears are fixed in one position.

Am I not getting something obvious?  Without a key in place I can't believe that the dog ear piece wouldn't slip on the magneto drive.

Offline steveale

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Re: EW magneto timing adjustment
« Reply #1 on: 30 Mar 2016 at 19:22 »
I read somewhere that you can loosen the points screw on some models with a taper shaft on the points side(non-keyed) and re-set the points break for the proper timing from that side.  Not sure if this mag has that type of shaft however and I will defer to the more knowledgable/experienced in this area.

Offline eddie

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Re: EW magneto timing adjustment
« Reply #2 on: 30 Mar 2016 at 19:59 »
If you rotate just the points, the magneto will NOT work correctly - if at all! The points need to be timed relative to the poles of the armature so that they open at, or just after, the point of maximum flux.
  If the mag on the EW does not time up correctly, I would suggest that the locating pin should be fitted in the mag armature and the drive dog replaced. Then remove the timing cover, and remesh the timing gears to give the correct timing. Leaving out the locating pin is likely to result in the timing slipping at some stage - especially on these mags with the small bolt retaining the gear on the small taper.

  Regards,
               Eddie.

Offline steveale

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Re: EW magneto timing adjustment
« Reply #3 on: 30 Mar 2016 at 20:48 »
Thanks Eddie, your insight on the points alignment makes absolute sense.  That's why you shouldn't rely on a single source when it comes to the internet.  :-)

Offline geomellish

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Re: EW magneto timing adjustment
« Reply #4 on: 31 Mar 2016 at 09:27 »
Thank you Eddie. When you say remesh the timing gears - is this fairly simple, ie can you just release and pull the upper gear out and re-insert it without messing anything else up?

I must say I wasn't expecting to have to start taking the engine apart just to re-time the magneto....

Regards, George


Offline eddie

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Re: EW magneto timing adjustment
« Reply #5 on: 31 Mar 2016 at 10:04 »
George,
             It looks as if you will need to draw the pinion off of the stub shaft that drives the magneto, then refit the magneto with the drive dog keyed to the armature. With the mag correctly timed, the pinion can then be refitted on the stub shaft. As the cam followers fit either side of the camwheels, it is pretty well impossible to upset the valve timing while you are doing this, but make sure you have the mag timed to the correct cylinder. To do this, remove the FRONT HT lead from the magneto and check that you can see the brass segment on the slip ring when the points are about to open with the mag fully advanced. Turn the engine forward until the REAR cylinder is at TDC with the valves rocking, turn the engine backwards about a quarter of a turn, then forward again to the correct timing point (about 40 degrees BTDC), then refit the timing pinion.

  Hope this helps,
                          Regards,
                                        Eddie.