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Buying backup mag, okay to replace either with an impulse mag?

S

SwimmingDragonfly96

Well Known Member
Obvious newb question. From conversations with lots of folks, seems like I have an impending mag failure on my hands. I'm not sure which mag I'm having problems with, so I was curious if I could get the impulse coupled mag as a replacement for whichever one fails?

I have the slick 4370/4373 combo, and I'm thinking of having the 4373 in my back pocket for when the time comes.

Thanks best community ever!
 
For the impulse mag to replace the non-impulse would require the addition of a spacer and longer studs. Not a casual change.
 
Impulse coupling mags can be susceptible to failure more so than a non-impulse magneto due to additional moving parts. How much time on the mags? The Slick mags require a 500 hour inspection, about $500 each. My mags will be due shortly, and I will be replacing the impulse mag with a Surefly, which will last the life of the engine while improving "hot" starting. What makes you think magneto failure imminent?
 
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Jpm757 said:
Impulse coupling mags can be susceptible to failure more so than a non-impulse magneto due to additional moving parts. How much time on the mags? The Slick mags require a 500 hour inspection, about $500 each. My mags will be due shortly, and I will be replacing the impulse mag with a Surefly, which will last the life of the engine while improving "hot" starting. What makes you think magneto failure imminent?
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Intermittent mag failure during my last flight. Inspected p-leads and wiring, and all things seem to be pointing to one of my mags. They only have 300 hours on them, and I figure having a drop in replacement compatible with both will reduce down time if I stagger the OH/IRAN times of the two mags. Basically have three mags, with two on the plane, and the other one OH'd and ready to go for down the line replacement.
 
As poster #2 said, not exactly a drop in replacement.
As poster #3 said, impulse mags have traditionally been more problem prone.
And as I’ll note, at some point in your ‘drop in ready to go replacement’ scheme, you may end up with a non-impulse mag in the left spot. You’ll have to re-wire your ignition switch to start on the right. (Not a big deal, just don’t forget).
 
On the other side of the coin, I ran dual impulse mags on my RV-6 for many years and never had a problem. One advantage is that you get to start on both mags!
I always use toggle switches on mags so rewiring the switch doesn't come into play.
 
I bought a spare mag to carry in my cherokee as insurance against my high time mags failing away from home. Question was whether to stock a 4370 or a 4373 as the back up. I found some documentation verifying that its not problem to mount up 2 impulse coupled mags on my O-320 so that's what I sourced. You do need a set of longer studs, the ~1.5" extension and two gaskets to put an impulse mag on the right side.
 
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