Left hand magneto removal question

[BigD]

Hello Mooney, sports fans, here’s my question, I am taking my magnetos off to send out for a pre-annual magneto overhaul. I got the right went off without too much fuss. However, the left one seems to be blocked in by the oil filter or battery. I can’t figure out how to take out the battery box. It looks like it might be into the Kevin firewall. Which leaves me the only option to remove the oil filter, do you all concur with this theory? Thanks.

 

 

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[Shadrach]

5 minutes ago, BigD said:

 

Hello Mooney, sports fans, here’s my question, I am taking my magnetos off to send out for a pre-annual magneto overhaul. I got the right went off without too much fuss. However, the left one seems to be blocked in by the oil filter or battery. I can’t figure out how to take out the battery box. It looks like it might be into the Kevin firewall. Which leaves me the only option to remove the oil filter, do you all concur with this theory? Thanks.

 

 

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Maintenance manual leaves a lot to be desired in terms of information.  I would think it far easier to get the mag out with the battery box removed.

[Sabremech]

The battery box can be removed but you’ll need another persons to be inside the aircraft to hold the nuts unless you have the avionics panels. If you have those, you can reach through and hold the nuts on the bolts with a wrench. That will give you plenty of room to remove the mag and also a chance to check your battery box for corrosion.

 

[47U]

48 minutes ago, BigD said:

I can’t figure out how to take out the battery box.

Yes, what Sabremech says.  He types faster than I do!

I remove the battery box for left mag work.  There are two bolts on the back of the battery box that go through the firewall, one of the nuts is near the parking brake valve.  There are also two bolts on the two struts that hold up the front end of the battery box.  One of those is in the footwell, forward of the rudder pedals.  If you’re lucky (like I am) I can get my right arm through the avionics access panel and reach all four nuts on the cockpit side of the firewall.  Otherwise, if you can’t get your arm down there, or, if you don’t have the avionics access panels (sometimes removed with a 201 windshield upgrade), someone will be standing on their head under the panel to reach the nuts.

I replaced the battery box bottom in 2010… in this pic you can see the bolt locations in the two front struts.

[Hank]

The left magneto is a pain. I've removed mine twice . . . It's much, much easier with the battery box off. It's no fun standing on your head to hold the nuts on the firewall. If memory is correct, the bolts aren't all the same, so mark which none goes where for easier reassembly. 

The first time, I spent about.an hour fiddling, twisting and turning and somehow finagled it out. Don't count on doing this, it was very frustrating and I was actually surprised when it worked.

Have a couple of big, clean rags to stuff into the surprisingly large hole on your engine once you get it off, too. I removed it, then paid an A&P to correctly reinstall and time it, while I helped around the edges and tried to not get in the way.

[BigD]

Thank you everyone. I did exactly what you all recommended: removed battery box- easy to remove mag. Yes, the two bolts are different that go I to firewall! I marked them. Now 18 business day wait for mags back. Grounded. Can’t wait - it’s been about 50” hours and FOURTEEN years since last overhaul! I actually have condensers on my mags to suppress radio static. Guy at Montana Mags told me those were supposed to removed years ago!



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[Pinecone]

Sounds like a good project for the down time would be to install nut plates for the battery box bolts.

[cliffy]

Or move the battery box to behind the rear wall in the radio access hole where it was put in later years-

LIKE I DID!

No STC required!  All Mooney parts and location so it qualifies as a minor mod (A&P sign off only)

The process in contained in AC 43.13  for reference.   

[Shadrach]

4 minutes ago, cliffy said:

Or move the battery box to behind the rear wall in the radio access hole where it was put in later years-

LIKE I DID!

No STC required!  All Mooney parts and location so it qualifies as a minor mod (A&P sign off only)

The process in contained in AC 43.13  for reference.   

I’ve always thought that aft of the cabin was a better location with regards to access, but given the light weight of the O360, wondered if it negatively impacted CG. 

[cliffy]

It helps with access and with CG with a 3 blade prop

I could easily go out fwd the way it was. 

Run your CG with 2 in front and no aft weight and see where you are. Then try all4 filled with 100 pounds in the baggage and see where you are.