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When to IRAN Slick Mag?

B

birddog486

Well Known Member
I know on the certified stuff they recommend a 500hr inspection but I've heard experimental guys go to TBO without touching the Mags except checking timing.

I'm currently time building in the RV-7 anywhere from 100-150 hours a month and at 500hr on the slick. I'd rather not pull the mag now but need some opinions on this.

The engine came from Lycoming 6-2019 and has one Slick 4373 and a Pmag with no problem starting and has about 60 RPM mag drops.
 
I believe the Slick mags actually have an AD on them where they have to be rebuilt at 500 hours, so it's more than just a recommendation. Yeah, we're Experimental, I know. But is that really where you want to roll the dice? There are plastic gears and other other components in a mag that really should be looked at periodically, even if it doesn't require a total overhaul or replacement.
 
Yes, in the old days, we ran Slicks until they had a problem. Then it became apparent that many of the problems were related to wear (and other factors I suppose) that could be caught and fixed at about 500 hours, so that is where Slick put the overhaul time. Sure, you can run them longer (run them until failure in fact….) legally in your experimental, but whatever is wearing out in there is wearing something else as well. We used to refer to Slicks as “throw-away” mags because they weren’t; economical to fix once they failed.

Remember that your mag doesn’t know if it is installed in a certified or experimental aircraft/engine - its going to wear the same way.

So I suppose that if your plan is to wear them out with the intent of replacing them with EI (or something else) when they have died, and you’re willing to have an inflight mag failure (because after all, you have two of them….but they might be the same age….), then you can run them until you have a problem - its legal. Smart? Depends on the kind off flying you do….

Personal anecdote - one of our airplanes years ago, just got progressively harder to start over the years - particularly when cold. It was such a slow progression that we just didn’t really notice it. It was my wife’s plane when we met, and she had bought it, not built it, so we really didn’t have any history on the mags - but it generally ran fine. Well….one day we got tired of the hard starting when cold, and replaced the mags - and the thing started great, very time! Took the old mags apart, and they were toast - the parts to bring them back to “serviceable” were more expensive than new mags. This was long before the “500 hour” recommendation BTW….

Some of that might help you with your decision….
 
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When you pull the mag don't forget to pull the PMAG for it's recommended 100hr inspection as well. :eek:

Disregard maintenance at your own (and possibly others) peril!

If you're opposed to doing maintenance maybe you should find another hobby.
Assuming you're training for a purpose, I wonder how you'll feel about the maintenance done on the aircraft you've been hired to fly?
 
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Walt said:
When you pull the mag don't forget to pull the PMAG for it's recommended 100hr inspection as well. :eek:

Disregard maintenance at your own (and possibly others) peril!

If you're opposed to doing maintenance maybe you should find another hobby.
Assuming you're training for a purpose, I wonder how you'll feel about the maintenance done on the aircraft you've been hired to fly?
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Jeez, tough crowd on a Sunday morning. Maintenance is not being Disregarded! Just to put you at ease Walt, The Pmag and the Massive plugs are inspected every other oil change as I've been averaging 10 days between changes. The NGK's are just tossed.
 
birddog486 said:
I'm currently time building in the RV-7 anywhere from 100-150 hours a month and at 500hr on the slick. I'd rather not pull the mag now but need some opinions on this.
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The question I would be asking is how much you value dispatch reliability and how much you fear being AOG away from home.
 
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RV8JD said:
Not to mention there are some important SB's out on the Slick mags. The SB's will be checked/accomplished during the 500 hour IRAN. Here is a sampling of some of the more critical ones:



BTW, Aircraft Magneto Service is a reputable shop:


As is Quality Aircraft Accessories:

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Thanks for the references, luckily this mag is new enough there's no SB's on it yet.
 
As some have correctly, pointed out, the 500 hour interval is for an inspection, not an overhaul.
The inspection document describes what to check, what requirement needs to be met, and what to do if it’s not. Generally means replacing the failed part.

An overhaul is specified as a requirement, if a prop strike has occurred. This is different from what it was years ago when it was just specified that you do a 500 hour inspection. An overhaul on a slick mag if done per the documentation is not economical because the individual parts are so expensive. You can buy an entirely new mag for cheaper than you can do an actual buy the book overhaul which requires replacement of many internal parts.
 
Ironflight said:
Yes, in the old days, we ran Slicks until they had a problem. ……
Some of that might help you with your decision….
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Yep. I have a friend who, ‘in the old days’, owned a 182, and flew his Slicks until he had an in-flight failure of the left mag. He landed, had it replaced. On the very next flight the right mag failed. Made him re-think the ‘run to failure’ mode.
 
do it

I have seen lots of marginal parts come out of the mags@ 500 hrs. replace them at 2,000 hrs with some cash back.
 
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