Quote: Has anyone considered that the "unfinished" rod journal lightening hole might be done that way to set the max. designed bobweight?
I feel your wrong for the following reasons,the crank stamped bobweight is heavier than the actual bobweight,so the crank needed to be lightened anyway,the hole was much smaller to begin with and the metal was peeled of surrounding the hole with a machinist pick,It could have easily enlarged itself under use(it was very thin)and found its way to the oil system and the all inclusive"most all internal balancing is done at the crank counter weights.So unless there is a new method of balancing That I'am not aware off,I have to kindly disagree.If I'am wrong I apologise.
The person who designed that crankshaft didn't know what your finished bobweight would be, the stamped number is just the maximum that could be used without having to add weight (heavy metal) to the counterweights. The counterweights are designed around this target bobweight. If your actual bobweight matched the stamped number you got very, very lucky. The rod throws are part of the equation just as much as the piston and rods are, you just don't consider this when final balancing is done, the bobweight is added to the rod throws when balancing. This is where my point comes in: if the rod throw lightening holes had been drilled all the way through you'd have to drill more material from the counterweights to balance it for your actual bobweight. Conversely, if your actual bobweight came in higher than the stamped number you might be able to remove material from those unfinished rod throw lightening holes instead of using Mallory Metal on the counterweights. Or, I could be hallucinating, again.
