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  #1  
Old 06-15-2018, 10:46 AM
PCHunt PCHunt is offline
 
Join Date: Feb 2007
Location: San Diego, CA
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Default Stubborn Piston Wrist Pin

Pulling #4 cyl due to failed exhaust valve. The piston wrist pin is being VERY stubborn.

Looking for a procedure (trick) to push the wrist pin out while the engine is still installed on the plane. Interference from the engine mount and adjacent #2 cylinder is making the job tougher.

Special tool? Heat, if so, how much?

Thanks!!
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  #2  
Old 06-15-2018, 11:57 AM
Electrogunner Electrogunner is offline
 
Join Date: Aug 2016
Location: Quarryville ,pa
Posts: 273
Default ATS

Aircraft tool supply sells a tool just for that very purpose. Or you could use a c clamp VERY gingerly. It should not take much pressure to push it out.
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  #3  
Old 06-15-2018, 12:59 PM
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PerfTech PerfTech is offline
 
Join Date: Sep 2010
Location: Yucaipa, Ca.
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Default

Quote:
Originally Posted by PCHunt View Post
Pulling #4 cyl due to failed exhaust valve. The piston wrist pin is being VERY stubborn.

Looking for a procedure (trick) to push the wrist pin out while the engine is still installed on the plane. Interference from the engine mount and adjacent #2 cylinder is making the job tougher.

Special tool? Heat, if so, how much?

Thanks!!
If you have a heat gun, use it to heat the piston up to about 600fht
and the pin will push out with ease. You will not hurt the piston or anything
at this temperature! Thanks, Allan..
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  #4  
Old 06-15-2018, 10:58 PM
PCHunt PCHunt is offline
 
Join Date: Feb 2007
Location: San Diego, CA
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Default Success!

I put Hoppes #9 on and let it soak. That helped.

But the answer (from a local A&P) was to use a rivet gun to semi-gently "coax" it out. (While supporting the piston to prevent damage to the big-end bearing.)

Didn't get to try Allan's idea of heating it, that would have been the next step. [But wondering how to determine when you have reached 600 deg. F. ?]

Allan probably has a tool for that!! And you could bet that it would work!

Thanks VAF.....
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  #5  
Old 06-16-2018, 03:53 AM
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plehrke plehrke is offline
 
Join Date: Sep 2006
Location: Defiance, MO
Posts: 1,400
Default

Quote:
Originally Posted by PCHunt View Post
[But wondering how to determine when you have reached 600 deg. F. ?]
Pretty cheap IR thermometers are available everywhere.
Get one for home and one for hangar. One of those tools you will wonder how you ever lived without it.
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  #6  
Old 06-16-2018, 07:52 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
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Default Not higher than 400F

Quote:
Originally Posted by PerfTech View Post
If you have a heat gun, use it to heat the piston up to about 600fht
and the pin will push out with ease. You will not hurt the piston or anything
at this temperature! Thanks, Allan..
Oil will burn off at 400F, like in ring grooves, etc, the piston does not get that hot in operation! So heat it yes, 600F NO.

It will become easy with heating, just heat and push you don't really need some specific temp. What happens is this: the piston was running hot, oil deposits built up in the gap when hot and now (when cool) has squeezed (shrunk) onto the pin.
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  #7  
Old 06-16-2018, 08:13 AM
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rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Agree with Bill. 400F ok, 600F not recommended.

WD40, gentle heat, work it back and forth with gentle pressure, should come out.
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  #8  
Old 06-16-2018, 08:51 AM
andyrv andyrv is offline
 
Join Date: Feb 2005
Location: Leawood, KS
Posts: 243
Default ATS Tool

I have the $69 Aircraft Tool Supply piston pin removal tool. It has worked great so far and you don't put any side load on the rod & bearings.
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