Piper SB411C

[murphey]

"Adapter Kit for Magneto Isolation Drive"

It's an SB, it's not "Mandatory" for Part 91. (No, I'm not kidding, it's in bright red letters!) In brief, it's a $3100 kit

"To provide a more maintenance free magneto drive system, a new magneto drive adapter and rubber cushion has been designed to isolate the magneto from the vibratory forces that could be transmitted by the driving components."

Now, can anyone provide a valid reason why this is such a wonderful idea, when overhauling both mags is less than $2K? Why I should go this route when the current mags were overhauled less than 50 hours ago?

I found one and only one reference in the FAA database, dated 2007:

"BEARING LW14227 CAGE DESTROYED AND APPROXIMATELY 50 PERCENT MISSING. THIS IS THE ENGINE SIDE BEARING OF THE LW15416 MAGNETO DRIVE ADAPTER (MAGNETO ISOLATION DRIVE FOR RT MAGNETO)ENGINE HAS 857 HOURS SINCE FACTORY OVERHAUL IN 2000."

 

[Tom-D]

These are used on the TSIO-360-series, on the PA 28R-201T, and are usually replaced at mag overhaul or replacement

and yes they do save wear on the mag drive gear. that sells used at $500

 

[Skylane81E]

The better question is why didn't it come that way in the first place

 

[murphey]

Because the SB wasn't issue until 2009 and this is a 1968 engine?

 

[Skylane81E]

Yes but many engines of that vintage did come so equipped. This SB is a good idea, but the cost seems a little extreme.

 

[murphey]

Yes but many engines of that vintage did come so equipped. This SB is a good idea, but the cost seems a little extreme.

A little extreme? I can get the same kit other places priced between $1700 and $2400. Lycoming retail is $3600 or so.