Ring gear diameter on flywheel

(quoted from post at 11:58:57 01/10/13) I'm about to put a new ring gear onto exsisting flywheel. Old ring gear came off very hard but OK. Noticed on diameter of flywheel where ring gear was seated that it's a different diameter than further away from this area. There are definately two diameters and the one further away from the flywheel shoulder is larger. This means that in cooling flywheel down and heating ring gear I must hope for enough growth/schrinkage to be able to slip/tap ring gear over a larger diameter than the diameter it actually seats on. I looked at old ring gear inside diameter and both outside diameters on flywheel and saw NO EVIDENCE of the ring gear spinning and causing the difference in diameter. No pickup or scoring of any kind. With a steel ring gear and a cast flywheel there should have been something noticable if ring gear had spun. It almost looks like it's been manufactured that way. Has anyone out there seen this slight difference in the diameter where the ring gear goes onto the flywheel, (looks like maybe .010" on a dia. larger at first then smaller against the shoulder)? Would be nice to know that new ring gear will fit OK onto this flywheel. Have no way of accurately measuring these diameters.

Thanks

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(quoted from post at 15:56:56 01/10/13) I believe that is the linear expansion rate, in which case you would need to use the circumference of the flywheel and gear. I think it would workout to require at least a 300deg delta between pieces.

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(quoted from post at 17:44:23 01/10/13)
I put new ring gears on flywheels twice, but on newer Fords. All I did was to have the flywheel in contact with the concrete floor in a fairly cold time of the year, then I set the ring gear on a concrete block and heated it with my O/A torch, slowly, keeping the flame moving. When I got the ring to where it was just under red hot all around, I set the flywheel up on a block and placed the ring on it and it took just a little tapping to bring it into place. I would be leery of the kitchen method, because you either have to carry both out doors very quickly, which is not real safe with something 500 degrees, or put them together in the kitchen which is probably even more dangerous.

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(quoted from post at 15:50:50 01/10/13)

(quoted from post at 17:44:23 01/10/13)
I put new ring gears on flywheels twice, but on newer Fords. All I did was to have the flywheel in contact with the concrete floor in a fairly cold time of the year, then I set the ring gear on a concrete block and heated it with my O/A torch, slowly, keeping the flame moving. When I got the ring to where it was just under red hot all around, I set the flywheel up on a block and placed the ring on it and it took just a little tapping to bring it into place. I would be leery of the kitchen method, because you either have to carry both out doors very quickly, which is not real safe with something 500 degrees, or put them together in the kitchen which is probably even more dangerous.

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Sounds reasonable. How good is your color differentiation? Anything primarily red in color is approaching 1000F.

TOH

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