390 balance shaft?

[BWL]

Hey, you fellas running 390s or 420s, does the balancer shaft make it a smoother running engine compared to the 196/212? I'm planning to build a new boat and repower to a bi block motor

 

[trinik7597]

The slave balancer is necessary if you are not having the crank balanced in the big blocks ..

 

[BWL]

That's what I figured since these single cylinder engines are unbalanced by definition.

 

[Moto Walt]

I took one out of a 270 Honda engine and it does good without it. Now it also doesn't turn a lot of rpm but it seems okay with what it's doing. Now if you want performance, find someone to balance the crank and pull the balance shaft out. It's hard to find a regular machine shop to balance a crank though.

 

[5hpminitech]

The slave balancer is necessary if you are not having the crank balanced in the big blocks ..

Total bs pulled them out years ago

 

[BWL]

Total bs pulled them out years ago

Unless you're me who can blow up any modded engine no matter how mildy built.

For clarity I'm not asking about modding a big block. I'm asking about stock big blocks in the marine environment.

 

[5hpminitech]

it will be fine without it and you cant truly balance a single cylinder engine

 

[ole4]

it will be fine without it and you cant truly balance a single cylinder engine

That is only true if you do not have a balance shaft. That is why they have them, they counterbalance the primary imbalance making the engine smoother. I can't think of a reason to remove it in BWL's marine application. Less vibration = less tingly hands while driving.

 

[BWL]

Thx, Ole. Man, I know about those tingly hands! I'll definitely be leaving it in.