While I was in a balancing mood I moved on to balancing the crank. My new .020” over piston is 50 grams heavier the original, plus I left the balance gears out last time. I wanted to bring the counterbalance value up to just over fifty percent. There were two holes drilled into the crank lobes from factory balancing, one twice as deep as the other. I calculated how much lead I’d need to get my 50% plus and it would fill the shallow hole and half the deep hole which would keep the end to end balance even. It worked out that a 5/8” coarse tap fit about right, so I threaded the hole to keep the lead in place. I also put a dimple inside to prevent the lead plug from ever turning.
I heated the crank lobes with a heat gun and melted the lead then poured. After checking the balance now, it worked out to almost 52%. Originally from the factory it was 46%. And 44% with the previous oversize piston.
My new piston rings gap at .008” on the top and .004” on the middle. I’ll have to take those out to .010”.
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