Dismantling my Nissan 90HP NS90A and couldn't help but notice this discoloration on the bottom half of one connector rod. My first thought was an overheating problem but upon closer examination it almost appears to be a deliberate addition to the rod. Second thought was some sort of balancing procedure done at the factory. Otherwise the crank and pistons looks good and operate smoothly. Have any of you mechanics every seen something like this? Thank you.
