Hi, A friend of mine bought a 331 kit for his 302 from a place on the west coast and this is a picture of the crank. Anyone ever see one drilled like this? Just wondering.
Not the best way to do it but he must have some pretty light rods and pistons, that's a lot of drilling.
If I am going to remove a bunch of weight I like to cut the counterweights down before doing the drilling to "fine tune". Big holes like that create "windage" at high RPM. Not to worry though, if it's just a street engine it will do fine, assuming it was balanced correctly.
Here are a couple of my Y cranks, the one on the right is the de-stroked "Brick" E motor crank. With a shorter stroke and light weight rotating assembly I had to remove better than 200 grams from each end, I cut the weights down instead of a lot of drilling. You can see the difference next to a stock crank.
Turning the cam out of the counterwieghts also has the advantage of letting you run the wiper tighter to the crank.
I have done alot of these that way, probably needed around 300 grams took out of it, must be some light rods and pistons, you will not see any performance disadvantage from this. However the best method is cutting the counterweights down to get it close and then fine tune by drilling holes
Thanks for the comments. I like the cut down weights better then all those ugly holes, by the way it's only drilled that bad on one end. Chuck
As was said ,cutting the counter weights first then fine tuning is really a nicer/ neater way of doing this Tony
I hope you got the balancer and flywheel or flexplate they balanced it with as part of the assembly!!!!!!!!!
That being the case I'll bet they balanced it early crank with a late damper. Your pix look like it is heavely drilled at both ends.
The start of this problem is the design of the crankshaft. When these lo-buck companies make these stroked cranks they don't take the bob weights into consideration. All they do is move the rod throws and do nothing to the counterweights >>>>.
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