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  #1  
Old 06-04-2020, 05:14 PM
ac_oldman ac_oldman is offline
 
Join Date: Mar 2018
Location: San Francisco, CA
Posts: 50
Default magento install/timing questions

I know the timing pin is removed prior to rotating the prop. Is it to be removed prior to rotating the magnetos for timing as well? I'd imagine so, but there's a post on this site that says otherwise.

Is it safe to keep the spark plugs in all but the #1 cylinder while timing magnetos, provided the wiring harnesses are both disconnected? will it damage a magneto to be timed while the wiring harness is disconnected?

Is it really a requirement to snap the impulse coupler prior to timing if you're doing a fresh install, prepped the prop to -25deg TDC prior to the install, and the mags agree with the prop timing mark?
I think snapping once timing is set to verify the IC retard is required.
any harm in snapping with a disconnected wiring harness?

test "bench timing" two mags, initially roughly timed with the pin in then removed, their grounds connected to each other and a buzz box should behave identically to timing once installed, correct? just to get the hang of it.

Last edited by ac_oldman : 06-04-2020 at 05:42 PM. Reason: adding reasoning for bench timing.
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  #2  
Old 06-04-2020, 06:00 PM
DavidAhrens DavidAhrens is offline
 
Join Date: Feb 2007
Location: Bakersfield, CA
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Default Magneto install

Maybe you can find someone local to walk you through the process? It isn't hard but I can tell from your questions you could use a little training. I wish I was closer to you, would be gald to help.
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  #3  
Old 06-04-2020, 06:29 PM
ac_oldman ac_oldman is offline
 
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Agreed! I do have someone who's helping me, this is prep work .
The kitplanes guide is excellent! However, I haven't found any written answers to any of the above - always good to have more information available for myself and others.

Sometimes there's disagreement between people who are familiar - for example, the timing pin question, where different posts seem to say different things.
Do you have any of the answers?

Last edited by ac_oldman : 06-04-2020 at 06:35 PM. Reason: fewer smileys.
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  #4  
Old 06-04-2020, 06:51 PM
Dave12 Dave12 is offline
 
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Default

Quote:
Originally Posted by DavidAhrens View Post
Maybe you can find someone local to walk you through the process? It isn't hard but I can tell from your questions you could use a little training. I wish I was closer to you, would be gald to help.
Agree completely. It?s not complicated, but experience is required.
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  #5  
Old 06-04-2020, 09:09 PM
DennisRhodes DennisRhodes is offline
 
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Keep in mind that the mags you are playing with are minimum $1000 each and a pin inadvertently or otherwise left in while the engine is rotated will destroy that mag . Take the advice given by above posters and it will be the best money you spend.
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  #6  
Old 06-04-2020, 09:34 PM
lr172 lr172 is offline
 
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Pin is used for initial placement of mag on engine. It should be removed before timing or rotating the engine or the mag.

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  #7  
Old 06-04-2020, 09:47 PM
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Steve Melton Steve Melton is offline
 
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there have been several people killed by prop strike while timing mags. pull one spark plug from each cylinder before beginning.
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Last edited by Steve Melton : 06-05-2020 at 06:56 AM.
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  #8  
Old 06-04-2020, 09:54 PM
ac_oldman ac_oldman is offline
 
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but if the wiring harness is disconnected from both mags how can it fire?

how does removing 1 from each help - wouldn't you need to remove both?
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  #9  
Old 06-04-2020, 09:56 PM
ac_oldman ac_oldman is offline
 
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oh, I think I finally figured it out. spark plug out == no compression, even if you have one spark.

But I still think my no-harness-connected would work fine.
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  #10  
Old 06-04-2020, 10:01 PM
ac_oldman ac_oldman is offline
 
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oh, no it wouldn't - there's a chance re-attaching the wiring harness might twist the magneto, so you'd want to check the timing again... except this time your harness is live.
maybe disconnecting all the leads would be easier than removing the plugs.
(though I will likely remove the plugs - no point risking it vs convention).

edit: yeah, what the heck would I do with the disconnected leads that will have a huge potential on them and potentially break the magneto if shorted. bad idea. convention.

edit: I understand the confusion now - when I said "leads" in this post, I meant the ignition harness to spark plug connections, not p-leads. I could understand why people would think this is crazy stupid.

Last edited by ac_oldman : 06-06-2020 at 01:17 PM.
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