Why do the number of cylinders on a V-engine effect whether a 60 or 90 degree design is preferable?

Question

This might be too technical a question for but I think I’ve missed something fundamental perhaps in geometry or physics so it might not be:

V6 and V12 engines often have cylinder banks at 60 degrees from one another, and V8 and V16 usually have them at 90 degrees from one another or an additional balance part is added.

Why is this? How is a V6 at 60 degrees smoother than one at 90 degrees? Is this even correct? Are there situations you’d want to use the ‘wrong’ one deliberately except to reuse a factory?

In: Engineering

Answer 1

With a V6 or V12, your crankshaft has either 6 or 12 mounts, at 60 or 30 degree intervals. Those need to align with cylinders at either the same angle, or an integer multiple.

Same thing with a V4 or V8, there will be 90 or 45 degree intervals. On a V10, it’s 36 degrees, so you’ll double it up and have 72 degree offset cylinders.