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10-04-2012, 08:26 AM
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Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,399
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The pit falls of not following directions. Metal in the Engine
There I was, listening to my engine idle with a rat a tat tat noise. Sounded much like an impulse coupler, which if I had any, I would have thought it was and never done a thing. But since I don't have any, time to figure out my new noise.
Im fortunate to have on my field, a retired 30 year NASCAR crew chief who has heard and seen it all when it comes to engines. He brought is handy noise tools and most importantly, his finely tuned ear. 'Hmmmm. Not heard that frequency before. Its in the accy case.' I dont like it when the expert is listening to my engine with a scowl and twisted face in confusion. 
OK pull the filter and cut. Nothing too disturbing. A few fine flakes and with a magnifying glass, magnets, lights n things, we are not convinced there is a problem. But there is enough head scratching going on to warrant further inspection.
Next remove the finger screen. As the fitting comes off, metal parts start dropping out. AHHH! Thats not good.
OK engine comes off. Sump off, accy case off. All on the bench in 1.5 hours. Found the culprit. A Magneto Bearing.
If you were a right side up only flyer, this bearing would just drop in the sump and sit there for many years to come without much fan fare. Me, well, not so much. So the bearing had the opportunity to traverse the sump and accy case enough to smash it to pieces. Enough to break a tooth off the idler gear for the right mag. These gears are $800. AHH!. A call to Lycoming confirmed that if you dont have a right mag, then you dont need this gear. WHEW!.
The rat a tat tat in the motor at idle was the idler gear with the missing tooth. With no load on it, ie no mag, it had the opportunity to make noise.
So we accounted for all bearing parts, broken tooth, magnafluxed a few things, checked this and that, and put her back together.
So how the heck did a mag bearing get loose in my case? Pretty simple. The guy who installed his electronic ignition(ME) did NOT read, understand, and follow the instructions. From the LSE manual....
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** Note- Magneto removal-
If you are removing a magneto that has a pilot bearing on the engine side of the magneto, be sure to remove the entire bearing with the magneto.
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Seems this was an important piece of information.
Here is a picture.

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Kahuna
6A, S8 ,
Gold Hill, NC25
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10-04-2012, 08:33 AM
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Join Date: Jan 2011
Location: Cumming, Georgia
Posts: 873
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Hey mike
Lots of nasty looking stuff there.......
What can be said were like kids at Christmas sometimes and just skim the
directions,and can not wait to get the new toy installed.
Buddy, you know I am thankful that the destructions stayed in place, mostly, and that this did not self destruct the engine.
Smilin Jack
Cumming, Ga
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N507H RV7, KJZP Jasper, GA
EAA690
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Retired Corporate Pilot CFI-AI, MEL
CE500, LRJT, HS25, C650, SBJT, CL60
Hunt Aviation, LLC.
Pilot Service, IPC's Biennials.
Comm Glider
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10-04-2012, 08:43 AM
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Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
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** Note- Magneto removal-
If you are removing a magneto that has a pilot bearing on the engine side of the magneto, be sure to remove the entire bearing with the magneto.
Which magnetos would fall into this category?
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Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
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10-04-2012, 09:24 AM
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Join Date: Jan 2005
Location: albuquerque, nm
Posts: 1,167
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Quote:
Originally Posted by az_gila
** Note- Magneto removal-
If you are removing a magneto that has a pilot bearing on the engine side of the magneto, be sure to remove the entire bearing with the magneto.
Which magnetos would fall into this category?
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My question exactly. I'm getting ready to install a second LSE. I'll be removing my left mag. The right one was never installed.
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10-04-2012, 09:38 AM
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Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,399
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According to the parts catalogs, the 67542 bearing is on all 540's A,B,C,D,E and G series engines. I was not able to find any on the 360 series engines.
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Kahuna
6A, S8 ,
Gold Hill, NC25
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10-04-2012, 09:38 AM
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Join Date: Aug 2007
Location: Chico (KCIC) , CA
Posts: 264
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Me too!
First thing I did when I started my engine swap was pull the mags off and install the cover plate on one side and the pickup on the other. Do I need to yank them off and take a look???
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10-04-2012, 09:47 AM
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Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
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Quote:
Originally Posted by Kahuna
According to the parts catalogs, the 67542 bearing is on all 540's A,B,C,D,E and G series engines. I was not able to find any on the 360 series engines.
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Thanks... that makes sense. I forgot you were talking about a 6 cylinder Lycoming.
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
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10-04-2012, 09:55 AM
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Join Date: Aug 2007
Location: Chico (KCIC) , CA
Posts: 264
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Thx! You slid your response in just before my post.
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10-04-2012, 11:01 AM
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Join Date: Jun 2006
Location: 8I3
Posts: 3,562
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Kahuna I have personally seen these bearing failures damage three engines. If the balls get knocked around by the crank the case will look like it got hit with a shotgun. They're only $21 apiece and I think should be replaced at the 500hr check or sooner. Thats if they're being used with a mag install. The thing you have to worry about now is when the bearing seized, how bad did it damage the bore in the case. Might warrant a weld/machining repair on the case. Usually they can fill the bore with weld and re-drill the big hole. edit: duh you're no longer using that hole.
There are some 360 engines that use the mag support bearing. Whatever is in the Cherokee 180, I think its the A4M.
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N9187P PA-24-260B Comanche, flying
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Not a thing I own is stock.
Last edited by rocketbob : 10-04-2012 at 11:12 AM.
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10-04-2012, 11:25 AM
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Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,399
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Quote:
Originally Posted by rocketbob
Kahuna I have personally seen these bearing failures damage three engines. If the balls get knocked around by the crank the case will look like it got hit with a shotgun. They're only $21 apiece and I think should be replaced at the 500hr check or sooner. Thats if they're being used with a mag install. The thing you have to worry about now is when the bearing seized, how bad did it damage the bore in the case. Might warrant a weld/machining repair on the case. Usually they can fill the bore with weld and re-drill the big hole. edit: duh you're no longer using that hole.
There are some 360 engines that use the mag support bearing. Whatever is in the Cherokee 180, I think its the A4M.
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The 360 A4M does not show the bearing.
Mine didnt seize. It fell out of its bore in the case. I failed to remove it when I removed the left mag a couple hundred hours ago when I went dual EI. When I removed the right mag on initial assembly for my single EI, I removed the bearing. Its pressed in, or at least a very tight fit. Mine required a bearing removal too to remove the first one. It should not fall out but it certainly can if there is no mag to retain it in there. I put the original one in a plastic bag and kept it(as seen in the photo). I have installed many 4 banger LSE EI's and never had a bearing to remove. Its why I failed to remove this one. Seen too many w/o them and I forget to check.
Case is fine. no sign of anything getting banged up.
Good to know that there is a failure mode of them seizing and causing havoc.
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Kahuna
6A, S8 ,
Gold Hill, NC25
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