Author Topic: stuck piston  (Read 578 times)

Offline jachenbach

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stuck piston
« on: 05.01. 2015 14:58 »
Trying to remove a barrel with the worst stuck piston I've ever come across. Been soaking with Kroil for the last 5 days, beating with a plastic deadblow hammer and heating with a propane torch. Then I started hitting it with a 2 pound brass mallet. Can't really get a cylinder very hot with propane. I'm wondering if I can safely use acetylene torch and rosebud tip? The cylinder is already .060" over, but otherwise in great shape, so I don't want to risk damaging it. Apparently the engine has been partially dismantled in the past, as there were no timing gears when I removed the cover. The inside case nut is loose, and I can raise the barrels so I can get it off and split the cases, I think, but I'm not sure that would make it any easier. No need to be in a hurry, so I can just continue soaking and maybe it'll loosen up eventually. What say the wiser, more experienced?

Online muskrat

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Re: stuck piston
« Reply #1 on: 05.01. 2015 19:03 »
G'day jachenbach.
If you can split the cases, remove the big end caps and lift it away from the crank. Then turn it up side down and work from under the piston (don't hit the con rod).
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
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Offline Bikergrandad

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Re: stuck piston
« Reply #2 on: 05.01. 2015 19:17 »
Hi to all. I had the same problem I did the same as you did.
              Now wrap the Engine in a towel, leaving the Barrel and piston "Don't Wrap".
                Put it in the FREZER for 24hr, take out tap the piston out it comes.
                 "Don't tell the wife"  Bob.
Too Old To Die Young.
      Eastleigh  Hampshire.

Offline Gerry

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Re: stuck piston
« Reply #3 on: 05.01. 2015 22:32 »
Hi Jachenbach, I had the same problem with a B25 that had been standing for God knows how long so I removed the head and lifted the barrel and rested it on two pieces of hardwood with rag underneath to stop bits of wood entering the case. Then using another piece of hardwood suitably shaped to cover most of the piston crown I used a club hammer to move the piston. Took a while but eventually succeeded. Good luck. Gerry

Offline jachenbach

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Re: stuck piston
« Reply #4 on: 06.01. 2015 01:26 »
I went ahead and put it in the freezer. I have a refrigerator/freezer in the shop (got to have extra beer storage) as well as freezers in the house and garage. Can't have enough freezer space when you like big game hunting. Anyway, we'll see what happens tomorrow. If the freezer doesn't work, I'll probably go ahead and split the cases as Muskrat suggested. Having access from both sides could be useful, and I have extra connecting rods if I bugger it in the process.

Offline Beezageezauk

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Re: stuck piston
« Reply #5 on: 06.01. 2015 09:40 »
I used Gerry's method together with a bit of heat and something that would be considered unconventional. 

To help the upward pressure I placed eight bolts of suitable length c/w nuts between the crankcases and the bottom of the barrel.  I screwed the nuts up to take up the space and then gave each nut about a half turn.  As the barrel started to lift I just kept repeating the process to maintain the pressure.  When the nuts came to the end of their threads I needed to replace the bolts with slightly longer ones. 

It worked for me but don't subject it to too much pressure.

Good luck,

Beezageezauk.


Offline jachenbach

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Re: stuck piston
« Reply #6 on: 10.01. 2015 01:58 »
Don't know why I didn't think of it sooner. Broke out the air chisel and with a drift bit drove the sucker right on down. Rings were rusted to the bore. The other cylinder/piston looks good. Interestingly, looks like one new connecting rod (on the stuck piston). No carbon or burnt oil on it at all, the other had what I would call normal buildup. I sure there's a story here (that I'll never know). Unstamped cases, new rod, pistons .060 over and the one that wasn't stuck looks hardly used. One of the scavenge tube plugs is butchered. I'm going to guess that someone threw a rod, broke the case, tried to rebuild it, seized a piston and sent it to the junkyard.