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  #1  
Old 03-18-2021, 04:39 PM
Larry DeCamp's Avatar
Larry DeCamp Larry DeCamp is offline
 
Join Date: Apr 2010
Location: Clinton, Indiana
Posts: 1,081
Default Lycoming exhaust valve reamer size ?

I need to ream a sticky exhaust valve on my 0320 w/Superior cylinders. Lycoming / Superior suggests to ream .4995 and mcfarlane sys .5005. Any experince to share on this ?
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RV-3B flying w/7:1 0320 / carb / Pmags / Catto 3b / digital steam
RV-4 fastback w/ Superior roller 360/AFP/G3X/CPI/Catto3b
Clinton, IN

Last edited by Larry DeCamp : 03-18-2021 at 04:43 PM.
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  #2  
Old 03-18-2021, 04:51 PM
moosepileit moosepileit is offline
 
Join Date: Dec 2010
Location: Louisville, KY
Posts: 696
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Brush Research FLEX-HONE Cylinder Hone, BC Series, Silicon Carbide Abrasive, 1/2" (12.7 mm) Diameter, 240 Grit Size
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  #3  
Old 03-18-2021, 05:38 PM
Larry DeCamp's Avatar
Larry DeCamp Larry DeCamp is offline
 
Join Date: Apr 2010
Location: Clinton, Indiana
Posts: 1,081
Default Thanks moosepileit

I assume the carbide brush is meant to remove deposits ? I am advised that sometimes the guide and stem simply gall each other fabricated to proper tolerance. If this is the case, I may need some metal removal on the guide. I need to tear it apart to define the objective. Thanks much.
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Larry DeCamp
RV-3B flying w/7:1 0320 / carb / Pmags / Catto 3b / digital steam
RV-4 fastback w/ Superior roller 360/AFP/G3X/CPI/Catto3b
Clinton, IN
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  #4  
Old 03-19-2021, 06:39 AM
Avanza Avanza is offline
 
Join Date: Jul 2020
Location: Vastervik Sweden
Posts: 57
Talking Reamer size

I have a IO-360 180 hp and I bougtht an adjustable reamer.
This way you can work your way to the final size 0.4995.
But I'm sure it will work just fine with a standard
0,4995 reamer.
It worked well.
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  #5  
Old 03-19-2021, 07:47 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by Larry DeCamp View Post
I assume the carbide brush is meant to remove deposits ? I am advised that sometimes the guide and stem simply gall each other fabricated to proper tolerance. If this is the case, I may need some metal removal on the guide. I need to tear it apart to define the objective. Thanks much.
No galling there. The valve stem is polished steel and the guide is something softer (usually bronze, but Lyc may have gone to something different) and is reamed to size. The are not fitted with the intent that they will wear into clearance. Wearing in this application is the enemy. Steel running in bronze is a time proven method with no galling.

Brush hones, when used properly, do well at removing deposits and lightly scoring (grit determines the depth of the scoring) the guide without any material removal and therefore clearance increase. You DO NOT want material removal in this effort. Scoring is mildly beneficial here as the valleys help to hold oil, just as they do in your cylinder walls.

Larry
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Last edited by lr172 : 03-19-2021 at 07:54 AM.
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  #6  
Old 03-19-2021, 08:19 AM
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rocketbob rocketbob is offline
 
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I've always thought a reamer is the wrong tool for this particular job....never had any subsequent guide issues once cleaned up with a ball hone. Its also a heck of a lot easier to set up and get done.
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