Harmonic Balancer Compatibility

[Sugo]

I am building up a 4.3L for my boat. The pulley for my V belt wont fit the harmonic balancer on the replacement short block. The replacement short block had a serpentine belt and the harmonic balancer has an offset. Can I use my harmonic blanacer off my original 4.3L . The blocks are of similar year (93) and the same casting (867). Both fit but they are not the exact weight or design thus my concern. I assume it should be fine however in my experience assumption usually ends up costing me in the end. Any thoughts would be appreciated.

 

[picklenjim]

Re: Harmonic Balancer Compatibility

Yes you should be fine using the original. All 4.3's are internally balanced.

 

[Struc]

Re: Harmonic Balancer Compatibility

Ummm... From everything I have read, the 4.3l motors are all externally balanced. Regardless of that, I'm sure you'll be fine with any version of harmonic balancer.

 

[dan t.]

Re: Harmonic Balancer Compatibility

Just to clear things up, the 4.3 is neutral ballanced on the harmonic ballancer, they are externaly ballanced on the flywheel only. Yes the ballancer will swap over with no problems.

 

[Sugo]

Re: Harmonic Balancer Compatibility

Thanks for the info. I am also using the flywheel off my original 4.3L (the same one the balancer is from) As it is more heavy duty and matches the rest of the hookups for the out drive, will this cause any balance issues?

 

[Struc]

Re: Harmonic Balancer Compatibility

And if you don't mind me jumping in on this thread...

Is there any advantage to using a heavier flywheel than the one that came with the marine engine? The one I got from my truck engine is much heavier than the marine one.

 

[picklenjim]

Re: Harmonic Balancer Compatibility

Thanks for the info. I am also using the flywheel off my original 4.3L (the same one the balancer is from) As it is more heavy duty and matches the rest of the hookups for the out drive, will this cause any balance issues?

Yes that would be the way to go. This new 4.3 your building, did it come from a car or truck or is it a marine 4.3?

 

[Sugo]

Re: Harmonic Balancer Compatibility

The short block did come from a truck. I compared the crank and pistons between the mercruiser short block and the automotive short block and they seem to be the same. Some marine builders are using upgraded cranks and pistons but many were not. I was able to pick up the 4.3L complete and running for $300. Only 40 000km. By adding an electric fuel pump, brass core plugs, gaskets, swapping over the cam, roller lifters, push rods, the heads, intake manifold, balancer, flywheel, water pump and all my marine gear, starter, alternator, distributor and so on, I am back in business for less than $500. (Not many 4.3L marine runners for sale here in BC) I know there is much debate about this approach. I have a 21ft Bayliner trophy with a new 200hp Yamaha on it and that is my baby. This boat is a toy for the lake so most of my boat budget goes to my fishing machine. Having two boat and staying married is a delicate art.