Has anyone tried to lighten the stock crank before balancing? My new pistons and rods are 251 grams lighter per cylinder. Would I be better off to get a lighter aftermarket crank? Thanks. Kim
If I were going to cut on the counter weights, I`d knife edge the heck out of it .I'd think about cutting the counter weights down. When I built the 451 stroker with a factory 440 steel crank, I cut the counter weights .120" in radius for use with 6.76" H-beam rods and Ross forged flat top pistons. Took very little drilling on the crank after that to balance it.
My pistons were 510 gms and the pins were 158 gms. Scat H-beam rods for 2.375 journal.
Ask those that are going to do the balancing for you.
Has anyone tried to lighten the stock crank before balancing? My new pistons and rods are 251 grams lighter per cylinder. Would I be better off to get a lighter aftermarket crank? Thanks. Kim
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^If you have access to a big lathe it is fairly easy to cut down the counterweights. Calculate how much bobweight needs to come off and then convert that to cubic inches of steel and you'll know how much depth to take off. We cut the counterweights down at the shop when we have to take off a lot of weight since drilling big holes in the crank is a bad idea. Once you know how to do it the task goes pretty quickly. If you do the calculation correctly you can often hit the balance number very closely so the final balancing only requires a dimple or two.
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I’m trimming the counterweights down to lighten the crank, not for clearance. Kim
I refer you back to post #2 where it says, "very little drilling"I’m just wondering if I were to take .120 off and then knife edged it if I would end up being too light.i wouldn’t want to have to add Mallory to it. Kim
I'd think about cutting the counter weights down. When I built the 451 stroker with a factory 440 steel crank, I cut the counter weights .120" in radius for use with 6.76" H-beam rods and Ross forged flat top pistons. Took very little drilling on the crank after that to balance it.
My pistons were 510 gms and the pins were 158 gms. Scat H-beam rods for 2.375 journal.
Ask those that are going to do the balancing for you.
Has anyone tried to lighten the stock crank before balancing? My new pistons and rods are 251 grams lighter per cylinder. Would I be better off to get a lighter aftermarket crank? Thanks. Kim
I always wondered about knife-edging... supposed to make the leading edge slip through the oil mist easier or something. Does it actually show measurable benefits on a dyno?
Notice that all low-drag airplane leading edges are not knives, but round and blunt in the front, with a long tapered trailing surface. Has anyone machined a crank that way instead?
race stuff!