ORIGINAL: downunder
ORIGINAL: gcb
Running cold puts undue stress on the rotating parts.
I found just the opposite. Running very rich and cold for 45 minutes the rod bush was polishing on the upper (load bearing) surface but the lower half still had all the original machining marks. The pinch (measured with a degree wheel) was also exactly the same as before I first started it. Just my observations
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Back in the old days, when ABC was new and relatively rare, and before the manufacturers decreased the taper ratio by a good margin, running some ABC engines rich would break the crankpin. I've seen it myself, so I know that it did happen. Gradually, everyone making the engines (well, almost everyone) got their act together and backed off the pinch a bit, lessening the probability of suffering damage when ran rich. This is my theory and we are talking about averages over a large group of manufacturers and models.
Ed Cregger