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Author Topic: freeing wrist pin  (Read 1724 times)

Offline Bootlegger

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freeing wrist pin
« on: March 24, 2021, 11:05:53 AM »

  What is the best way too get the rod moving on the pin, I have crock potted it for about 24 hrs and soaked it with P B Blaster and it still stuck with castor, what should I do next ?  Thanks
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Gil Causey
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Offline kenneth cook

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Re: freeing wrist pin
« Reply #1 on: March 24, 2021, 02:57:32 PM »
                Heat it

Offline Dennis Toth

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Re: freeing wrist pin
« Reply #2 on: March 24, 2021, 04:29:24 PM »
As Ken said "heat". If you can get the backplate off take a heat gun and point it up the back and heat the conrod. Try to work the rod free (wrap the rod with some cloth and don't force it just keep heating and working it.

Best,     DennisT

Offline Air Ministry .

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Re: freeing wrist pin
« Reply #3 on: March 24, 2021, 06:37:18 PM »
JUMP ! .

 VD~ S?P

B#!&^ etc .  A HEAT GUN , Aimed Up Its thingo , seems to be the trick . CRC / WD 40 Blasts , heated .  So it gloops and liquifies .

Still can take a bit to lever , rod or piston . Dont get to agro & bend something . Scientific application of Brute Force , levers & packers . Heated & Sprayed at each shift. Initially .

Wotkindoff Engine isit .

Offline Bootlegger

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Re: freeing wrist pin
« Reply #4 on: March 24, 2021, 06:37:29 PM »
 The heat did it, used a small torch and heated the rod until it came loose, thanks for the help/ideas... y1    #^    n~
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Gil Causey
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Offline C.T. Schaefer

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Re: freeing wrist pin
« Reply #5 on: March 25, 2021, 05:12:28 AM »
heat gun and 2+2 or gumout choke/carb/intake cleaner. Cut the gum.     Also.......patience.

Offline BillP

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Re: freeing wrist pin
« Reply #6 on: March 25, 2021, 06:59:15 AM »
I'm curious why the crock pot didn't work. What temp did you do the crock pot on and did you use straight antifreeze? I clean engines on low temp and use high temp (boiling) to break loose seized parts like wrist pins and mccoy cyls. They don't always break free on low temp.
Bill P.

Offline Bootlegger

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Re: freeing wrist pin
« Reply #7 on: March 25, 2021, 06:46:34 PM »
 Bill, I used straight anti freeze, and the temp was 200 f   to 220 f at all times the pot was set on low. I found a small torch and heated the rod and got it to work free.  Thanks for the advice/help every one,  I'm Obliged... H^^
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Gil Causey
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Offline BillP

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Re: freeing wrist pin
« Reply #8 on: March 26, 2021, 08:00:55 AM »
Gil, thanks for the info. What engine are you working on?
Bill P.

Offline Bootlegger

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Re: freeing wrist pin
« Reply #9 on: March 27, 2021, 06:20:36 PM »
 It was an early Fox25 single by pass..   Hope that helps
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Gil Causey
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Offline Peter in Fairfax, VA

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Re: freeing wrist pin
« Reply #10 on: April 04, 2021, 02:53:03 PM »
Glad this worked out well.  Myself, I prefer oven heat, as it is very even and temp controlled.  I'll start at 225, then go to 250 or 275 if I must.  10 minutes in my shop's toaster oven, which is quicker than a crock pot.  Also, an unattended 10 minutes where I do other stuff.  Typically, I am going through a collection when I do this, so there are others tasks to occupy my time while the engine heats.

As others say, brute force is a bad idea, as it is easy to bend rods.  A good test for a bent rod is to insert drill bits, steel rods if you have them, into both ends of the rod.  It will be obvious if bent, and easy to tweak by grabbing the drill bits.  A bent rod will create weird binds that can be felt, especially if you have developed good mechanical feel.

Offline Joe Ed Pederson

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Re: freeing wrist pin
« Reply #11 on: April 04, 2021, 03:43:32 PM »
I had a particularly stuck wrist pin in an E-bay OS Max .35S that was new or had been run very, very few times.  Glad I checked it.   I tried the crock pot and antifreeze.  I tried a Monokote heat gun.  Nothing.  I didn't try the oven.   Probably should have.

I finally took the head off and used a popsicle stick in the exhaust slot to take the cylinder lining out, then forced the wrist pin out with a dowel.  I lubed it back up with after engine run oil and reassembled.  I haven't run it yet.

What finally worked may not be the best method, but it is what I ended up doing. 

Joe Ed Pederson

Online Lauri Malila

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Re: freeing wrist pin
« Reply #12 on: April 04, 2021, 03:54:36 PM »
Totally off-topic, I build my pin/piston groups stuck. Zero clearance or a couple microns interference fit.
That way nothing can get there to make it more stuck, heat conduction is near ideal, and removal is easy by heating the piston assy to 140..150°C on a heater plate (no flame!) and the pin can be lightly tapped out. L😜

Offline Dan McEntee

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Re: freeing wrist pin
« Reply #13 on: April 04, 2021, 06:14:53 PM »
Totally off-topic, I build my pin/piston groups stuck. Zero clearance or a couple microns interference fit.
That way nothing can get there to make it more stuck, heat conduction is near ideal, and removal is easy by heating the piston assy to 140..150°C on a heater plate (no flame!) and the pin can be lightly tapped out. L😜

   On a related note, this just popped into my head. I had been going through some Fox .19s and some .25s, basically the same engine. I forget which version it was, but I read somewhere at the time that there are no wrist pin retainers , and that was because the wrist pin has a slight taper and is seated in place. you need to make sure that the wrist pin goes back in the way it came out, or it won't!!  You have to remove the liner first, then get the piston off if the rod will slide on the pin where it needs to. Then with the piston/rod out, you can tape the rod out in the correct direction. I might have read this on the MECOA web site while I was researching the parts I was looking for, or maybe even Peter in Fairfax, VA might have clued me into it as I had bought some parts from him at that time.

    Type at you later,
    Dan McEntee
 
 
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Bootlegger

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Re: freeing wrist pin
« Reply #14 on: April 05, 2021, 09:13:53 AM »

 Dan did I understand correctly that the 19 and 25 have the same piston and liner ??
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Gil Causey
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Offline Dan McEntee

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Re: freeing wrist pin
« Reply #15 on: April 05, 2021, 09:44:16 AM »
Dan did I understand correctly that the 19 and 25 have the same piston and liner ??

    NO!!! i did not say that. They are basically the same engine as they share the same crank, rod, back plate and such. The R/C carbs are the same and the version with the bolt on venruri is the same. You need to work on your reading comprehension skills and really study the parts listings on the MECOA site. They explain a lot about the different versions. You may best be served to just find a p[arts engine like you to get the parts you need.

   Type at you later,
    Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)


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