The single housed mag, dual pack mag, the problematic mag… call it what you want. The design sounded like a good idea at the time because of the less complexity, less weight, less production cost, and allowance for more accessories to fit on the engine. However, after the single housed mag was put into service many problems in the field surfaced. These issues include, but are not limited to, cams loosening, impulse couplings failing, magneto movement, and ultimate failure of the magneto housing resulting in the magneto departing the engine. All these failure modes result in either a drastic reduction of power or complete failure of the engine.
There is even the potential that internal engine damage was created by operating at an out of specification ignition timing, a problem you may not find out about until much later. The cost is also significantly higher for the single housed magnetos, presumably due to the liability surrounding the design. If you have the O-320-H2AD or O-540 with the single housed magneto design and it has not been an issue for you YET, it’s only a matter of time. Air Plains has an engine replacement solution for this problematic mag on the Cessna R182 and the Cessna 172N.
For more information on engine upgrades contact Air Plains today.