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IO-390

Ron B.

Well Known Member
On an EXP119 once the vacuum pad cover is removed , is anything needed other than a new gasket in order to mount a B & C standby alternator. Are the correct drive gears already inside. I would say it's good to go as the alternator has to be turned slightly for the spline to line up in order to insert.
Thanks
 
On an EXP119 once the vacuum pad cover is removed , is anything needed other than a new gasket in order to mount a B & C standby alternator. Are the correct drive gears already inside. I would say it's good to go as the alternator has to be turned slightly for the spline to line up in order to insert.
Thanks

I can only speak of my 40a PlanePower standby alternator that I recently install on the vacuum pad. It included a gasket, and I'm sure yours does to. Easy installation... Just torque to the recommended value and you're done.

Great peace of mind when flying IFR....
 
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IO-390 and B&C backup alternator

One thing to anticipate: Looking from the back of the alternator, the lower left nut (goes on a stud), seems nearly impossible to get to. So -be prepared to get out the propane torch and cherry a box end wrench to bend it and make a custom tool to reach that nut. I made mine into an L shape to get around the wider part of the alternator, and adapted the other end of the wrench to accept an allen wrench. Your situation may vary, depending on the space you have to the firewall. Some folks routinely bend up tools for a job, for others it may seem like a destructive mutilation that doesn't occur to them!
 
One thing to anticipate: Looking from the back of the alternator, the lower left nut (goes on a stud), seems nearly impossible to get to. So -be prepared to get out the propane torch and cherry a box end wrench to bend it and make a custom tool to reach that nut. I made mine into an L shape to get around the wider part of the alternator, and adapted the other end of the wrench to accept an allen wrench. Your situation may vary, depending on the space you have to the firewall. Some folks routinely bend up tools for a job, for others it may seem like a destructive mutilation that doesn't occur to them!

We already have encountered this situation and welded up the wrench to torque that nut. Problem we had was not knowing anything about the P-Mag and not wanting to remove it. Torqueing the nut was nothing. Getting the nut started on the stud with the mag. in the way was something else.
After getting it done I was wandering if we missed anything , thus was my question.
Thanks for the replies
 
One thing to anticipate: Looking from the back of the alternator, the lower left nut (goes on a stud), seems nearly impossible to get to. So -be prepared to get out the propane torch and cherry a box end wrench to bend it and make a custom tool to reach that nut. I made mine into an L shape to get around the wider part of the alternator, and adapted the other end of the wrench to accept an allen wrench. Your situation may vary, depending on the space you have to the firewall. Some folks routinely bend up tools for a job, for others it may seem like a destructive mutilation that doesn't occur to them!


FWIW, my lower left nut is easy to get to.
 
We already have encountered this situation and welded up the wrench to torque that nut. Problem we had was not knowing anything about the P-Mag and not wanting to remove it. Torqueing the nut was nothing. Getting the nut started on the stud with the mag. in the way was something else.
After getting it done I was wandering if we missed anything , thus was my question.
Thanks for the replies

I'll be happy if I can get the nut started on the stud. How in the world did you get the nut started on the seemingly inaccessible lower left stud without removing the magneto or is that simply standard procedure?

Spent an hour so far and no joy. Would appreciate any ideas.
 
I took a 3/16" diameter soft hose (very flexible) and taped the nut to the end (I used electrical tape). The flexible hose allowed the nut to stay lined up with the thread while I turned the hose. Only took a few tries after I came up with that plan. Had a dozen ideas tried before getting to this one. We did remove the oil filter for better access.
I ended up rotating the P-Mag to get access to the connector after completing the above and from what I can tell , re-timing is not a difficult task once we provide power to it. I would check if removing the P-Mag is a big deal, I doubt it is.
 
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