Disassembly of a stuck Forty Minus SJM

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Charles uk
Posts: 4951
Joined: Wed Feb 27, 2008 4:38 pm
Location: Maidenhead Berks UK

Re: Disassembly of a stuck Forty Minus SJM

Post by Charles uk »

The piston is too low in the bore to move it far with the grease nipple method.
Make it idiot proof and someone will make a better idiot.
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Stinch
Posts: 11
Joined: Thu Aug 13, 2020 1:21 am
Location: Connecticut

Re: Disassembly of a stuck Forty Minus SJM

Post by Stinch »

The piston top edge was stuck just above the exhaust port. I figured if I tried the grease method it probably would have moved but would have stopped when the grease leaked into the exhaust port.

I bought a short section of aluminum pipe that was 1.75" in diameter with a 1/8" wall. This pipe fitted nicely over the connecting rod and yet contacted the piston skirt evenly. Used a friends 20 ton hydraulic press and was able to push the piston out the top. The piston fought every step of the way. The rings have minor corrosion at some points along the edges and will be replaced. Despite how hard the piston was to get out, the piston and cylinder walls look to be usable.
Attachments
20200926_140536 (Medium).jpg
20200926_100623 (Medium).jpg
Forty Minus - SJM 50761
Forty Plus - FPL 1890 E9
Century 100 - LLS 624 A5
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