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-   -   Ignition question (https://vansairforce.net/community/showthread.php?t=147206)

bob888 03-02-2017 12:56 AM

Ignition question
 
I have a Slick 6393 mag on left and Electroair ignition on right. The Slick has retard points but I have no need for vibrator or Slickstart because the Electroair can start the engine. Question is what to do with the mag wiring so that it won't fire early and kick back. One possibility is to leave it off until after start but eventually someone will start with it on and potentially cause damage. What have others done about this?

bob888 03-02-2017 12:57 AM

I should add that I have toggle switches and not the usual key switch.

DanH 03-02-2017 07:13 AM

Perhaps ground the magneto p-lead while the starter is engaged?


vic syracuse 03-02-2017 07:29 AM

Personally, I don't like adding any complexity to the ignition switching. It is supposed to be simple and reliable. :)
Can you label it off for start? That's a first choice.

Another way, IF you feel you have to "move a switch" is to use a 3 position toggle, labeled OFF, START, RUN. The middle position will do nothing (you do have to remember to jump the poles on the back of the switch so the mag stays grounded). But it should prevent the switch from being thrown to the run position during a start.

Vic

Auburntsts 03-02-2017 07:31 AM

The easiest solution is to start only on your EI and keep the mag off until the engine is running.

I have two mags and no EI, but the principle is the same. My left mag is a retard breaker and I start on that mag alone. I don't have a traditional keyed rotary ignition switch either so I manually select L, R, or Both for the mags but I do it with one rotary switch vs 2 toggles. My starter is a physically separate switch.

Jasonm 03-02-2017 09:07 AM

Quote:

Originally Posted by bob888 (Post 1154365)
I have a Slick 6393 mag on left and Electroair ignition on right. The Slick has retard points but I have no need for vibrator or Slickstart because the Electroair can start the engine. Question is what to do with the mag wiring so that it won't fire early and kick back. One possibility is to leave it off until after start but eventually someone will start with it on and potentially cause damage. What have others done about this?

I have a similar setup to you and am using the keyed ignition switch like this one - http://www.aircraftspruce.com/catalo...?clickkey=5735

My Lightspeed is on the "Right" side and my mag on the "Left". I simply turn the key to the "R" position and start. The "L" position is not live while starting. To do my mag check I will move the key to the "L", observe the RPM change and then move the key to the "BOTH" position.

rv7charlie 03-02-2017 10:30 AM

I'm pretty sure there's a drawing for this in the Aeroelectric Connection.

Mike S 03-02-2017 10:42 AM

This is really a wiring question, so I moved it to the correct forum----applies to virtually all models not just the 10

Paul from Flyleds 03-02-2017 06:04 PM

Aeroelectric article
We used two mags in the RV-10 and wired them as per Bob's method.




bob888 03-02-2017 08:57 PM

Thanks all. Second question for those with one electronic ignition and one mag...how much rpm drop is acceptable when the ei is cut out for a mag check? I'm seeing 150 rpm drop from 1700 rpm when I switch off the ei.

vic syracuse 03-03-2017 05:50 AM

Quote:

Originally Posted by bob888 (Post 1154622)
Thanks all. Second question for those with one electronic ignition and one mag...how much rpm drop is acceptable when the ei is cut out for a mag check? I'm seeing 150 rpm drop from 1700 rpm when I switch off the ei.


It will vary depending upon the mixture. Max allowed is 175 RPM, so 150 is OK and close to normal. Sometimes leaning will lessen the drop. The key is that the engine is still running smooth, which assures you that all of the cylinders are firing.

Vic

GregMac 03-03-2017 05:57 AM

Ignition question
 
I've got the same retard mag on the left like you Bob, with Lightspeed right. No Slick Start. I've started the IO540 for the first 12 mths (100 odd hours) with both left and right ignitions on. Have the same individual switchs, and have had absolutely no issues regarding kickbacks. I recently contacted Champion (Slick makers) their advice to me was that there was vertually no chance of the UNBOOSTED retard mag firering until the engine had reached started RPM, and then it would fire at the normal 25*. So because the unboosted mag was not contributing and the electronic was effectively doing all the starting then I should consider starting only with the electronic on, I've now adopted that routine and it's working well. Your RPM drops are consistent with what I'm seeing. Cheers from Western Australia

Jesse 03-05-2017 06:13 AM

Quote:

Originally Posted by vic syracuse (Post 1154675)
It will vary depending upon the mixture. Max allowed is 175 RPM, so 150 is OK and close to normal. Sometimes leaning will lessen the drop. The key is that the engine is still running smooth, which assures you that all of the cylinders are firing.

Vic

...and if you can see all EGT's, if they all increase, all plugs are firing.


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