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6 Cylinder P-Mag Bearing Failure Design Change

Strikhedonia

Well Known Member
I am in the middle of my condition inspection and I sent in both my P-Mags in to be inspected following Robert's bearing failure. They haven't been inspected yet, but I called Brad today and he explained that the bearing that failed is the same one that has been used for years in the 4 cylinder P-Mags. It is considered very reliable.

As an extra precaution they are now installing a shim/washer that will contain the bearing inside the 6 cylinder P-Mag should it fail. Thus saving the hours of work removing the sump that Robert went through. He also noted that the 4-cylinder version already had an oil seal that would prevent the smaller front bearing from throwing debris should it fail.
 
Chris,

You captured the highlights. This is what I know:
- Only one forward bearing failure has been reported (200-6XL).
- This is the same bearing used for years in the four cylinder 114 series ignitions that have provided good service. Environment is harsher in the 114 than the 200 Series, where the shaft coupling is A) in-line and B) rubber cushioned.
- eMag has high confidence in the design, but as a precaution new production 200 series ignitions will have a thin bearing shield added to the front of the bearing stack so in the event of a similar failure, material can be retained inside the ignition and not pass to the engine.

I ordered my new Thunderbolt Cold Air Sump IO-540 with dual six cylinder pMags.

Carl
Three flying RV builds, all with pMags.
 
Chris,
. Environment is harsher in the 114 than the 200 Series, where the shaft coupling is A) in-line and B) rubber cushioned.
- eMag has high confidence in the design, but as a precaution new production 200 series ignitions will have a thin bearing shield added to the front of the bearing stack so in the event of a similar failure, material can be retained inside the ignition and not pass to the engine.

Carl
Three flying RV builds, all with pMags.

Not sure what basis you have for the above, the rubber cushions were added do to mag failures on the 6 cyl engine, then impulse couplers were removed do to more problems. The 4 cyl engines never had any of those issues.
 
Not sure what basis you have for the above, the rubber cushions were added do to mag failures on the 6 cyl engine, then impulse couplers were removed do to more problems. The 4 cyl engines never had any of those issues.

The rubber cushions are part of the magneto drive on the Lycoming 540. There are two drive lugs on any magneto designed for the 540 whether they are Slick or Bendix. The rubber pads sit in a cup attached to the mag drive shaft. The drive lugs on the magneto are inserted between the rubber pads as the magneto is installed. EMag Air merely put the same kind of drive lugs the 6-cylinder EMags designed for the 540. I am not familiar how Continental engine mag drives work.
 
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