Quote:
Originally Posted by PAUL K
Thanks for posting.
We've had many balanced assemblies come through our shop. Seven of the eight rods had never been taken out of their wrappers and it was obvious the pistons weren't all scaled.
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Treading lightly here. We have NO Pontiac engines in class this time. However, the vendors I am talking about DO sell Pontiac Cranks and rods. I don't want to throw any vendor under the bus, we need them. However, nothing from Butler or KRE are being discussed here at this time. But that's not the point. I am personal friends with the Rodney and David Butler. But when I buy stuff from them, I check every piece anyway. I have NEVER had a out of spec. part from Molnar. Doesn't matter, I check every rod anyway. Piece of mind. To Paul's point, I think these mass marketed kits from Eagle, Scat, Summit and others are "Batch balanced". Meaning they weigh a sample of pistons and a sample of rods, come up with a bob weight, and then balance a couple hundred crankshafts or more to that same bob weight. No proof of my guess here, but for the low price they are selling this stuff for, I can't imagine each rotating assembly being weighed and balanced individually. Too labor intensive.
IMO, a "balanced assembly" that is off 14-16 grams on each end would not be noticed in a mild street build run a few thousand miles a year. It wouldn't be right, but a catastrophic failure is unlikely. The little Ford off nearly 100 grams on an externally balanced crankshaft would have some vibration that could be felt and a shortened engine life.