Quote:
Originally Posted by Patrick L.
Hmmm, interesting. My thoughts are that there is too much runout in that wheel. I've always thought that about .002" was the accepted number. How much more than that would cause your problem, I guess I'm not too sure. But, I think your .008" is way too much. That said, taking off the few thousands to true it up, I wouldn't think it would need to be rebalanced. Personally I would try that. I understand your predicament, time is money and we know how much time it takes to pull these critters back apart. I'm sure we'll all be interested to hear about the outcome.
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Ok, some additional food for thought.....
If I take 0.002" off of the flywheel, how much do you think that removed material will weigh? Using a clock face for a visual reference for this illustration, theoretically if I take 0.002" off the flywheel face, then I will be taking approximately 0.001" off from the 4 o'clock to the 5 o'clock position along with 0.001" from the 7 o'clock to 8 o'clock position and approx. 0.002" from the 5 o'clock around to the 7 o'clock position, ...or about 120° of the flywheel. The remaining 240° of the flywheel perimeter is not to have any material removed. While I can probably calculate the weight of that material which would be removed, by guess I feel like it would be at least 10 grams, ...which in the world of balance should/would be noticeable on a flywheel.
Since you mentioned recalling the 0.002" runout number, I went to the source to find exactly what that number is. On page 218 of the Service Bulletins, it mentions a number of 0.005" as the maximum number for being eccentric and without wobble. It states to measure this at the hub and rear face of the large diameter. The issue with this number is we are speaking of a multiple disc flywheel that is only been machined in the clutch hub (...in the center). So if the "wobble" is to be measured on the multiple-disc hub, it is only ½ the distance to the outer perimeter of the flywheel. Therefore, if we use the 0.005" maximum of wobble on a multiple-disc flywheel, then on a regular Model-A flywheel that max number would likely double if the radius of the flywheel measurement were doubled too. With that mindset, then 0.010" would be the maximum number of run-out. Would it not??