Question about balancing rotating assembly

gregcon said
When you are a normal dumb-***, you sit around arguing about which spark plug or motor oil will turn your car into a Top Fuel dragster. When you start to feel smarter, you start espousing the merit of equal length, tuned exhaust systems and camshaft profiles. Then, when you are an expert you are confident enough to start the balancing and rod/stroke ratio discussions.

So anyway, just for the sake of mentioning it....I owned a '70 340 Swinger that I bought from the original owner in 1986. It had about 113K miles on it and ran great. There is absolutely zero chance anyone had ever been into the engine. When I did take it apart finally, I found one journal had 318 rods instead of the 340 rods like the rest of the engine. Significantly lighter. I did a lot of reading up in Hot Rod and Car Craft and determined the engine had to be shaking violently, even though it showed no signs of it and ran as smooth as butter.

So you’re ok to pay someone to balance the rotating assembly and they do that?

Luck would have it my **** would shake. Can’t tell you how many balance jobs I’ve had to correct. A bad one was a BBC that the moron who owned changed out the fly wheel from external to internal balance and didn’t think to even look at them before he swapped them out.

I forget how far off that end was, but I couldn’t even spin the crank to 100 RPM before the crank was jumping out of the machine.

I call the idiot and verify that was the FW he used in the car. He says yep. I say did it shake? He says smooth as butter.

He was either lying or stupid, because I had him bring in the main bearings because his dumb *** took it apart and sure enough, the mains showed distress.

But it was smoooooooooooth as butter. Right.