balancer/balancing ?

[SteveRacer]

I am currently in the process of rebuilding my engine and would like to get it balanced. I'm hopeing for a mid 11 sec combo with shift points below 6000rpm. what balancers are suitable for this? Is SFI required? Where's the best place to get them? I will be useing +.030 trw's, stock rods with arp bolts. Are these pistons heavier than stock and will they complicate or add cost to the balancing job. If so, would a different harmonic balancer or flexplate be benificial? what percentage of balance is best from a performance aspect? I'm so confused Thanks

 

[Ormand]

The Buick "Power Source" has a good, brief discussion of balancing. If you are going to balance the engine, there are two ways. Stock is "external" the engine is balanced with the harmonic damper and flex plate, so they are all part of the balance job. Stock harmonic damper and flex plate have a built in "inbalance" to match the crank. Stock balance requires you to use pistons/rods that weigh the same as stock. Better is to use a balanced crank, with a harmonic damper and flex plate that are both balanced on their own, not as part of the crank job. There is another thread, which discusses having the stock damper and flex plate balanced. This is the "internal" balance. With this, there is not much cost difference between heavy pistons and light pistons. Some balancers will charge by the ounce if they use "Mallory metal", but it won't be a big deal.

 

[SteveRacer]

Thanks for your reply Ormand. Anyone else have any advice?

 

[MSDGN]

As long as you plan on staying in the 11's the stock balancer and flexplate are fine but if you have any intentions of running faster then it would be a good idea to go with the SFI stuff...if you have it balanced with the stock stuff and then later decide to go with the SFI stuff you can't just bolt on the balancer/flexplate...you'll have to get it balanced again...as for balancing if it's primarily a street car then stick with the stock spec...if it's going to see track duty most of the time then I'd balance it 50% of reciprocating weight