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  #51  
Old 11-11-2022, 07:24 AM
vic syracuse vic syracuse is offline
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Default Check the bearing

We do find a few of these PMAGS with bearing play every year, so please do check them. EMAGAIR has been very quick at truning them around.

Vic
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  #52  
Old 11-12-2022, 03:41 AM
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Default

Quote:
Originally Posted by vic syracuse View Post
We do find a few of these PMAGS with bearing play every year, so please do check them. EMAGAIR has been very quick at truning them around.

Vic
Not saying I would do that, but what would happen if you ran it to failure? I like to understand the edge cases.
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  #53  
Old 11-12-2022, 06:21 AM
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Quote:
Originally Posted by rv8ch View Post
Not saying I would do that, but what would happen if you ran it to failure? I like to understand the edge cases.
Probably the same thing that happens when a neglected impulse coupler fails, parts fall into the accessory case and cause bad things.
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  #54  
Old 11-12-2022, 08:06 AM
Dad's RV-10 Dad's RV-10 is online now
 
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Default

FWIW, I emailed P-Mag to ask some questions about the bearings in the 6 cylinder P-mags vs. the 4 cylinder units. I have 6 cylinder P-Mags but the engine hasn't been run yet (other than on the test stand).

Regarding the bearings in the 4 cylinder P-Mags, Brad replied that the 4 cylinder units have one large bearing and one smaller bearing in the stack whereas the 6 cylinder units have two of the larger bearings on the main drive.

The small bearing in the 4 cylinder stack has recently been enlarged.

I'm not sure if that means that older 4 cylinder units sent to P-Mag for service will get the enlarged smaller bearing or if it means that new production units come with the enlarged smaller bearing? But I thought it was worth noting here, since there was discussion of bearing wear and inspection.
  #55  
Old 11-12-2022, 11:21 AM
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rv8ch rv8ch is offline
 
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Quote:
Originally Posted by Walt View Post
Probably the same thing that happens when a neglected impulse coupler fails, parts fall into the accessory case and cause bad things.
Thanks Walt. Doesn't sound like something we want to happen.
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  #56  
Old 11-12-2022, 11:35 AM
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Toobuilder Toobuilder is offline
 
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Quote:
Originally Posted by rv8ch View Post
Not saying I would do that, but what would happen if you ran it to failure? I like to understand the edge cases.
Magnet air gap is also something to consider. Aside from the trash generated from a bearing coming apart in your accessory case (accessory gear timing is kind of important), magnet misalignment caused by an out of true shaft is likely to cause a shutdown, or worse, a mistiming event.
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  #57  
Old 11-12-2022, 03:32 PM
Northernliving Northernliving is offline
 
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Default

Quote:
Originally Posted by robert@jonesrv10.net View Post
I made some cooling shrouds for the front of the PMags out of Carbon Fiber. They wrap half way around the PMag and have a 1" blast tube hooked to them. They were easy to make and make the blast tubes more effective. I used the rounded end of a 2X6 for a mold and tapered it just a little to make the shroud easier to get off the mold.
Hi Robert,

Would value seeing a picture of what you made if you donít mind posting.

- Brian
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  #58  
Old 11-17-2022, 05:29 PM
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gmcjetpilot gmcjetpilot is offline
 
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Yes bearings were changed and retrofitable. I talked to Brad he said no need to change if play and rotation are good. A non mandatory change but small incremental changes, r
continuous design improvements. But the original design is fine and many PMags are in service with 1500 hrs or more, with no bearing issue. Just inspect you are good.

Yes bits in accessory case is bad. The PMag is not the issue but some aftermarket gears made for a time with less hardness. This is the same non impulse magneto gear used on your magneto. Two things: The load on gear is light and many of these softer gears have no issue. Second the issue was not wide spread, but there were a few cases of premature wear.

Another good reason to remove PMag yearly to inspect shaft play and rotation, as well as gear. You can assure you have the better or OEM Lycoming gear through markings or hardness test. A genuine non impulse Lyc gear is $450. A non certified gear is $225., which is equivalent to the Lyc gear.
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Last edited by gmcjetpilot : 11-17-2022 at 05:52 PM.
  #59  
Old 01-02-2023, 06:55 PM
robert@jonesrv10.net robert@jonesrv10.net is offline
 
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Quote:
Originally Posted by Northernliving View Post
Hi Robert,

Would value seeing a picture of what you made if you donít mind posting.

- Brian
Send me your email and I will send you some. Mine is robert@jonesRV10.net
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  #60  
Old 01-02-2023, 07:11 PM
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GalinHdz GalinHdz is offline
 
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Quote:
Originally Posted by robert@jonesrv10.net View Post
Send me your email and I will send you some. Mine is robert@jonesRV10.net
Can you post a copy of the photos? There are more of us that would love to see your design.
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