Reality: A new steel flywheel will cost you less than welding an old one.

Theory: If you wanted to resurface a steel, not cast iron, flywheel, it could be done by running a continuous bead from the ID to the OD of the wheel, then facing it off. That would give an even hardness across the surface and would probably work out well. That's the only way I'd say welding the working surface of a flywheel could be done with satisfactory result. You'd probably need a welding procedure for the particular type of steel from which the original flywheel was machined. It may need to be stress relieved or normalized or another post-weld heat process.

Comment: I agree that most of the hysterical responses you got were meaningless, except they all pointed to the fact that it is far easier to create a problem welding a flywheel than it is to do the job properly. Avoiding hard spots is one area of concern.


There is another problem that was hinted at and that is weldability. Not all steels are equally weldable. But they are many many times more weldable than cast iron.

Supposing this was a flywheel for a Stutz Bearcat, it'd probably pay to develop a weld procedure and have it properly performed. But the Stutz's wheel is probably cast iron so the issue is moot. For a more modern vehicle, it will most likely be better to buy a new steel flywheel.

R.