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P-MAG Annual/100 hr. maintenance Requirements

Walt

Well Known Member
Posted for those folks that prefer to not read the P-MAG manual and may neglect the recommended maintenance.

Maintenance:
Annual or 100 Hr. Inspection (whichever comes first):
1. Check E-MAG web site for most recent Service Notes (www.emagair.com page “Service Notes”) and verify equipment is current with all updates.
2. Ignitions come with a (one-time trigger) thermal sticker that will trip (turn from light ash color to gray or gray/black) if case temperatures exceed 200 degrees (F). If tripped, review blast cooling and/or other ventilation issues that affect ignition cooling. Keep ignition temperatures below 200 degrees.
3. Ohm check plug wires (see “Ohm Check” above), and examine spark plugs for signs of unusual wear or build-up. Gap plugs per instructions above. Replace auto style plugs with new ones after 100 to 125 hours. When re-installing auto style plugs with auto plug adapters, review plug/adapter installation guidelines above.
4. Remove ignition and examine shaft and drive gear condition. Note: Ignition disassembly is not necessary (and if done may void your warranty). Look for excessive play (lateral and axial). Shaft rotation should be free, with no catching, flat spots, or grinding. The shaft on “P” models (with internal alternator) will have a push-pull rippling effect as the shaft turns and the permanent magnets pass the rotor poles. This is normal and expected. If a P model ignition does not have this magnetic ripple, the unit requires additional (shop) service.
5. Replace older 1/16” cotter pins with larger 5/64” cotter pin. Inspect and secure the ends to prevent movement. The smaller pins have been in service for some time, but we’ve have occasional reports of pins coming loose and/or breaking.
6. Examine control plug and coil plug connections. Tighten to 4-5 inch pounds. Verify there are no stray wire strands. Verify all control wires use the Adel clamp strain relief.
7. Reinstall the ignition, and verify proper operation. Review Setting Ignition Timing instructions above. For P models, re-verify minimum operating speeds when running on internal power (see Minimum Operating Speed test above.)
 
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Thanks Walt, just crossed 90 hours so looks like I will have something to do when I get back from Osh. I knew there was a 100 hour but your post puts all of the details in one nice little package. I'm assuming your posting this as you are seeing a lot of people not comply with it. :)
 
Thanks Walt - I'll be looking forward to this in the coming weeks as well. One thing I want to do is to swap the ignitions left/right to see if my mag drop numbers move with the ignition. I have a higher RPM drop on one engine during the run-up and I can't quite figure out why. Does anyone see a problem with swapping the pmag positions?
 
Thanks Walt - I'll be looking forward to this in the coming weeks as well. One thing I want to do is to swap the ignitions left/right to see if my mag drop numbers move with the ignition. I have a higher RPM drop on one engine during the run-up and I can't quite figure out why. Does anyone see a problem with swapping the pmag positions?

If you have one P-Mag running top and the other running bottom plugs, the one running the bottom plugs will have a higher RPM drop during the mag check.
 
If you have one P-Mag running top and the other running bottom plugs, the one running the bottom plugs will have a higher RPM drop during the mag check.
Thanks Ray - that's exactly what Brad told me - I had them as you describe, one on top and the other on bottom. I changed them to be split top/bottom and it made some difference - probably about 10-20 RPM if I recall correctly. I still have a bigger gap than I believe I should have.

Lycoming says that max magneto drop should be 175 RPM and the max difference between the two should be 50 RPM. Emagair does not list their recommendations in the documents I've found. My drops are about 120 and 80, so I'm barely in the Lycoming recommendation, and I want to see if I can make it better, or at least understand why it's different. Based on other posts on VAF it can be a lot of different things - problem with a plug, a plug wire, wire in the pmag loose, etc.
 
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