Steve Porter 1 Posted October 15, 2016 Share Posted October 15, 2016 Evening All, i am trying to replace the bearings in said engine, everything has been removed without problems i now have to remove the con rod. the problem is the con rod sits in a grove within the crankcase so any position apart from top dead center the rod will not have room to be pulled off, at TDC it will move aprox half way off the crank pin then the piston stops it moving any further. am i missing a trick? Steve Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted October 15, 2016 Share Posted October 15, 2016 Have you took the piston liner out Steve, to give the piston more room? Quote Link to comment Share on other sites More sharing options...
Steve Porter 1 Posted October 15, 2016 Author Share Posted October 15, 2016 Hi Denis, every thing has been removed apart from the piston, con rod and crankshaft, it is very frustrating i have never struggled like this and i have replaced many bearings on many different engines Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted October 15, 2016 Share Posted October 15, 2016 Remove piston? Quote Link to comment Share on other sites More sharing options...
Geoff S Posted October 15, 2016 Share Posted October 15, 2016 How would get the gudgeon/piston/wrist pin out when the piston is still in the cylinder? Even with the liner removed as Steve says he's already done, there wouldn't be room. Somehow, in some position there's got to be enough room to pull the big end off the crankpin. Geoff Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted October 15, 2016 Share Posted October 15, 2016 I'm having trouble visualising this groove - any chance of a photo? I can't think why you can't try removing it a BDC... Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted October 15, 2016 Share Posted October 15, 2016 Get a wooden lever down there Steve and do the heat/cold sequence Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted October 15, 2016 Share Posted October 15, 2016 You may find that the con rod is stuck on the gudgeon pin , this in turn stops it from sliding back off of the crankpin. Try soaking in some boiling water for a few minutes . Once it can slide along the gudgeon pin it should clear the crank ok. Quote Link to comment Share on other sites More sharing options...
Brian Neasham Posted October 15, 2016 Share Posted October 15, 2016 Are you sure the con rod is sliding fully to the rear on the gudgeon pin, sometimes a bit of solvent is needed to clean off any congealed oil that is stopping it from moving fully to enable it to give clearance to slip off the crank Quote Link to comment Share on other sites More sharing options...
Hangar 9 nut Posted October 15, 2016 Share Posted October 15, 2016 Put crankshaft at tdc and it should come off ! Quote Link to comment Share on other sites More sharing options...
Steve Porter 1 Posted October 15, 2016 Author Share Posted October 15, 2016 Thanks for replies, the con rod is very free on the crank pin but as you pull the con rod off the piston hits the case. iwill add photo of grove in case. Steve Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted October 15, 2016 Share Posted October 15, 2016 Some OS engines have a hole in the rear of the crankcase to remove the gudgeon pin. Edited By Braddock, VC on 15/10/2016 22:06:30 Quote Link to comment Share on other sites More sharing options...
onetenor Posted October 16, 2016 Share Posted October 16, 2016 Have you tried rocking about TDC while attempting the removal. a little heat applied direct on the con rod may help too Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 16, 2016 Share Posted October 16, 2016 There should be a hole in the back of the crank case.When the gudgeon pin is lined up with this you will probaaby see a teflon pad in the end of the pin. I normally remove this with a thin self tepping screw just screwed in enought to grip. IT shoul pull the pin out with it. If not then further gentle screwing into the hollow pin will remove it. Some pistons have a fine wire circlip to retain the gudgeon pin.These are removed with very thin nosed pliers. This can be "fun" as can replacing them. Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted October 16, 2016 Share Posted October 16, 2016 I'll state the obvious, the liner has to be removed before access is gained to the gudgeon pin, . Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted October 16, 2016 Share Posted October 16, 2016 Steve has said that he has removed the liner, and SF engines don't have a hole in the crankcase to pull out the gudgeon pin so I'll go with the suggestion that there's some gunge stopping the rod sliding back on the gudgeon pin. I've stripped SF 61s many times and occasionally I've needed to tease the rod back with pliers in order to clear the crankpin. Try the hot water or solvent inside the piston, it should allow the rod to ease back far enough to come off at TDC. Quote Link to comment Share on other sites More sharing options...
Steve Porter 1 Posted October 16, 2016 Author Share Posted October 16, 2016 Evening all, well engine doctor was correct, a little heat ( more than i would normally use) plus some solvent and Bingo it came away no probs,it was stuck on the gudgeon pin, must have been hot as the rear bearing came out as the crankshaft was withdrawn and the front bearing didnt take much to push out either. Thanks to all for your sugestions Steve. Quote Link to comment Share on other sites More sharing options...
Geoff S Posted October 16, 2016 Share Posted October 16, 2016 Where there's a will there's a way. Glad you got it sorted. Reminds me of what my dad told me when I had my motor cycle gearbox in bits. "Don't worry, there's only one way to put it back together." Fortunately he was right Geoff Quote Link to comment Share on other sites More sharing options...
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