Quote:
Originally Posted by oldspert
I bought a Model A engine that has a counterbalanced crank. Was inspecting the crank and found it only has what I consider tack welds on each end of the weights. It has the safety bolts holding the weights to the crank, but very little weld. I'm not sure that is sufficient to keep everything from coming apart. I can weld more area to the crank, but should I have it rebalanced? After V'ing out the area and adding weld, it might be a wash on weight. The crank was done many years ago by a place called Ron's in Ohio. Still in business?
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Yes, while Ron Miller passed away last year, his son BJ and their crew are still building many A & T engines. There was/is a video on YouTube by Hagerty that featured the Hagerty crew filming their Model-A engine being rebuilt by the same Ron's Machine in Shandon, OH.
As for the counterweights you mentioned on your engine, that is the same basic process they have been doing for years, ...and pretty similar to the way I do it. Think about this. Ron's guys machined the counterweight where the radius of the weight exactly matches the OD of the crankshaft web. There is a Grade 8 bolt that holds the weight tightly to the web. The tac-welds are there to keep the weight from rotating on the bolt however it is the bolt that is keeping the weight stationary. This bolt is in constant tension unlike the connecting rod cap stud & nuts that are in constant compression and then tension in each revolution. Because the crankshaft has been dynamically balanced, the weights remain 'friendly' with the crankshaft as it is spinning.
If you still have concerns regarding the tack welds, then TIG weld across the width of the weight on both ends and then re-balance. Likely if the weight is actually fuse-welded to the web (-without using any filler rod), then you may not even need to re-balance it.