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Removing mag drive gears

mgregory176

mgregory176

Active Member
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I have an IO-540 C4B5 that I am converting to dual EFII. I removed the mags, drive cushions, and the spacer but I can't seem to figure out the removal of the gear. The manual doesn't show any retaining clips or bolts. Is there a secret to this?
 
a little heat

Are you talking about the gear on the mag? Remove cotter pin and nut, if gear does not come off shaft with fingers and rag, just warm gear with hot air blower for 2 minutes and the gear should come off easy. Torch heat is not needed. It is just a snug fit on the shaft, some just slide off. Never needed to use my gear puller.
 
is removal mandatory?

I also am considering one EI; if you don't remove the drive gear in the case, does it rattle around potentially causing grief?
....or is ok to leave in there, and just install a cover plate over the drive hole?
thx
 
flyboy1963 said:
I also am considering one EI; if you don't remove the drive gear in the case, does it rattle around potentially causing grief?
....or is ok to leave in there, and just install a cover plate over the drive hole?
thx
Click to expand...

I haven't installed an EFII but someone I know did. He did not remove the idler gear and it came loose and caused lots of damage in the accessory case.
 
FasGlas said:
I haven't installed an EFII but someone I know did. He did not remove the idler gear and it came loose and caused lots of damage in the accessory case.
Click to expand...

The idler gear is not retained by the mag or mag gear. It is retained by a machined pad on the accessory case. You should know most of the idler gears are all connected. Pull the left idler gear and your camshaft doesn't rotate. Pull the right and your prop governor doesn't spin.

Larry
 
Last edited:
The mag drive gear p/n LW-19096 is not an idler gear, it only drives the mag, and should be removed. There is a pilot bearing in the case that the end shaft of the mag drive gear goes into and it should also be removed also. I installed an EIS system and had to remove these parts.
 
lr172 said:
The idler gear is not retained by the mag or mag gear. It is retained by a machined pad on the accessory case. You should know most of the idler gears are all connected. Pull the left idler gear and your camshaft doesn't rotate. Pull the right and your prop governor doesn't spin.

Larry
Click to expand...

You can tell this to the guy with the trashed 540 that didn't remove the gear.
 
Mags and gears

Always remove the gear that is at the end of the mag.
The mag is the only thing that holds this gear in place.
The gear will slide straight out of the accessory case.
The idler gear that is off to the side of the mag is fully supported and stays in the accessory case.

Robert
 
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