I have flywheel apart at the moment for a complete re-build. I tried the recommended 'rap the magnets' to reveal possible cracked/ broken ones. I found 4.
These show no signs of previous cracking, as the made a clean break each time. Am I rapping them too hard? I gave the open end of each a sharp tap on my bench vise. The others all stood up to the treatment and ring well.
Allan from down under.
Possibly too hard. If it were me doing the test each one would break but not because the magnets were weak but because i was hitting them.
Allan,
I had similar results to you with a couple of 24 flywheels I stripped a few years ago. Recently, I stripped the magnets off a 26-27 flywheel and not one magnet broke when rapping them. Most of these magnets recharged on my recharger to lift 4 pounds +, a few would dead lift 6 (no grinding ends or cheating either, as is, straight off the flywheel).
I hit them reasonably hard too (holding them in the apex of the v between forefinger and thumb, which allows for only so much of a "rap", I think.
Thanks to Ron Patterson for informing me to do this years ago, the magnets that broke back then would have gone into an engine had it not been for this forum.
Regards,
Bede
Better if they go in your hand hard rap or not. There has to be existing damage there if they split. On the other hand, properly installed they might never break.
Keep doing what you are doing Allen! Good ones do not break!
Model T magnets are forgings, if they break there is a flaw.
Ron the Coilman
I'd much rather see them break from a hard rap on the bench instead of inside the transmission. You've cut down the odds of having some future headaches there Alan.
Garnet