Balance Crank vs Imbalance Crank ?

[tkb289]

Ok engine experts out there … have some questions:

Right from the Ford Racing catalog, here are (3) Boss 302 based motors that each have different Balance / Imbalance






- Why are they different, any pros and cons as to which method is 'better' and why ?


- Does engine Balance / Imbalance have any relation to Flywheel or Driveshaft balance as well ?


Thanks!

[4pipes]

Tim, maybe this helps,
http://www.fordmuscle.com/forums/all...-question.html

[tkb289]

Dave,
Thanks ... that does shed some light on the subject and it makes more sense. Sounds like a lot of things, car parts included, it comes down to time and money.

[Mark O'Neal]

Originally Posted by tkb289

Ok engine experts out there … have some questions:

Right from the Ford Racing catalog, here are (3) Boss 302 based motors that each have different Balance / Imbalance






- Why are they different, any pros and cons as to which method is 'better' and why ?


- Does engine Balance / Imbalance have any relation to Flywheel or Driveshaft balance as well ?


Thanks!

They are different because the crankshafts are different.

Neutral is always best...after that, keep it as light as you can. The higher the rpm range you intend to run the more important it becomes.

[patrickt]

Originally Posted by tkb289

- Does engine Balance / Imbalance have any relation to Flywheel or Driveshaft balance as well ?

The short answer is "Yes." I'll use my own engine as an example. Originally, my 428 from the factory was designed to be externally balanced. The original flywheel was a special one that is weighted specifically to work in conjunction with the crankshaft. When I had the engine totally rebuilt, I had the engine internally balanced so that I could use any neutral balanced flywheel (and not a special externally balanced one). Balancing an engine is an art, it takes time, and the special metal that is used for plugs is not cheap.

[RodKnock]

I believe those Ford Z heads have raised exhaust ports, so your exhaust might have to be tweaked. Although with a small block, there's certainly much less concern than an FE.