Another Example of a less extreme kinfe edge A15

Quote:

from what i've gatherd zane, when you offset grind a crank, you take metal out of the inside of where the conrod big end fastens around the crank.

effectivley, what happens is the centre of where the conrod used to fasten (on the crankl) is now moved further away from the middle of the crank. effectivley giving the crank a longer stroke without making anything bigger.

consecuently though, smaller conrod big ends are required to fit the newsize crank, which makes offset grinding a bit off a 2sided blade.

there is benefits in torque to be had in offset grinding, but going too overbord reduces crank strength.

ill draw a pic in paint to explain a bit easyer how the metal is removed.




this masterpiece is the cross section of where the conrod bolts onto the crank.
it shows - or tries to - how the stroke of your crank can be increased, by removing metal from certain parts of the crank. for ease-of-draw i left off counterweights etc...

If you make the pistions and rods lighter you need to change the bob weight when you balance the crank.

So a rebalane of the crank is needed if you knife edge it? Maybe if would be just as easy to buy one and be done with it.... How much do they go for roughly?

if your building an engine usually you get the bottom end balanced any way
so you just do it then go get every thing balanced, would be alot cheaper than buying a performance crank

The cheapest thing to do would be just buy a built engine.