Examination revealed the magneto's distributor gear
Seeking to develop a longer-lasting distributor gear
for racecars, Performance Plastics of Cincinnati turned to PEEK polymer supplier Victrex USA.
A custom injection molder in Cincinnati has developed a polymer distributor gear
that the company said can provide longer life even under harsh racing conditions.
When the removed magneto was disassembled, the distributor gear was found to have failed Part Total Time: 673.
Disassembly of the removed magneto (p/n 10-500556-101) found the distributor gear to have failed.
The distributor gear
was loose in its bearing, allowing the rotor to contact ignition studs, wearing them excessively and increasing the gaps, resulting in the magneto failing to produce spark.
The first instance was discovered as a result of engine roughness during a pre-takeoff engine run-up: The l/h magneto was not firing properly and, upon inspection, the distributor gear
(p/n: 10-357586) was found to be missing approximately ten teeth.
This spacing problem causes the finger on the distributor gear
to rub on the distributor block, p/n M3820.
Investigation revealed the magneto's distributor gear
had 13 missing teeth (all pieces were recovered).