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Magneto life

dothetime

Well Known Member
One of my mags a slick 4301 just crapped out, giving me a reason to install the
Pmag I have had on the shelf.
I have 750 on the Hobbs, I know about the recommended 500 hour inspections.
So I am curious how many hours were on your mags when they quit working.
Thanks
Dave
 
So I am curious how many hours were on your mags when they quit working.
Thanks
Dave

One lasted couple thousand hours and was replaced still ticking. Another one seized after only 200 hours it was in affected SB group.
 
Accomplish the SB, for reliabilty

One of my copper electrodes type (pre SB 1-15A) distributor gears failed at about 425 hours.

Accomplish the 500 hour inspection and comply with the SB that replaces the copper electrode with stainless ones. They will be Bullet proof after that.
 
I have had them fail after 200-300 hours; however, they usually dont just fail. It is not uncommon for them to satrt to have timming drift after 50 hours. Most people don't realise this unless they check the timming at both Compression AND Exhaust. The standart timming check is to sync them on the compression stroke, but if you keep spinning the prop, they should also be synced on the exhaust stroke, because that is where they are firing the other two cylinders.
Magnetos also often get weak without failing (again in the 200-300 hour range).
Look up ignition stress tests and you will find procedures for testing your ignition system.
 
One lasted couple thousand hours and was replaced still ticking. Another one seized after only 200 hours it was in affected SB group.

Interestingly enough, the mag that was in the affected sb range, did not fail due to the issues covered in the sb. It actually failed due to a seized bearing. We don’t hear about failed bearings very often.
 
130 hours on an impulse couple Slick

I had two problems with an impulse coupled Slick. Hot starts went from easy to impossible in only a couple of flights, but then the mag failed a run up check (engine just quit on the LH mag). Sent the mag in for repair--the impulse coupler had failed and the internal timing was way off. Went back to analyze engine data and it was evident I'd had a problem for awhile, but never knew it because the mag always passed run up checks. Swapped the mag for a SureFly SIM, so now I have a spare.
 
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