Question: Could there be a correlation between putting a lighter aluminum drive pulley on a B230 and rod failure?

Back when I was messing with VW airhead motors the game was to put a HEAVIER pulley on to promote smoother revs. Gene Berg was famous for these.

Now does this same thought work with the Volvo red block? Does the heavy stock harmonic balancer promote longer crank/rod life?

I just lost a B230F to rod failure. I realize overheating was the main culprit but wonder if that combined with the lighter weight Unitek pulley did the damage.

Trying to learn a bit from my mistakes...

I don't think so. The B230's were pretty well balanced, with good bearing placement, and low friction....
BUT
The 83? to 88 B230's were made with rods that were 9mm, which were 4mm thinner than the original 13mm rods. They also moved the bearings around with the thinner rods, then reverted to the original setup because it was less prone to rod failure. Was the engine from these years?

I'm not an expert on engine harmonics though, so someone who is much more expert than me will give you a better answer.

FYI: Engine was 91 B230F. Not sure what size that makes the rods.

I posted the same question over on Turbobricks where a lot of folks use various alloy pulleys. Consensus there seems to be the lighter pulley would not effect rod wear. Still, I gotta wonder why the big stock HB was put on originally.