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Flywheel Gear Shrink Fit

Stu I have a 1961 Ford tractor Model 641 that I am rebuilding the engine. I have pulled the motor from the tractor and I noticed that the flywheel
ring gear was a little worst for ware, so I bought a new 134 tooth gear. The shop manual says to heat the gear to 360 degrees and place on flywheel (shrink fit). That didn't work even with a little persuading with a hammer and block of wood. I even put the flywheel in the freezer for 3 days, then heated the gear and it still would not go. I then measured the bore of the gear and the OD of the flywheel and found that there is .025" differance. That sounds like way to much for a shrink fit. Do I have a gear with an undersize bore?? I don't think I have a big enough hammer to overcome that much shrink. Your expert help is what I'm looking for!!!

Bob G I don't have a clue what the specs of the flywheel and ring gear are but I replace one a few years ago and I just heated the ring with a cutting torch. I did have get it real hot tho. my 8n book says 350 degrees and people talk about heating them in their kitchen ovens but I think you would need the oven real close to where you are working on it. you have to be fast!
Might check with CNH for the flywheel dia and ring gear specs. Might ask at a local engine rebuilder what they think.
good luck

mark sr I wonder if it's an aftermarket not quite to spec issue? It's been a long time since I installed a starter ring but all I ever did was freeze the flywheel and use a hammer - didn't own a torch back then.

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