Kahuna
Moderatoring
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....
====
** 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.
====
Seems this was an important piece of information.
Here is a picture.
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....
====
** 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.
====
Seems this was an important piece of information.
Here is a picture.