Harmonic Damper & Balancer Questions

[Ranz1]

What is the purpose of both? Does price (cheap stuff) affect the function/purpose of the balancer? Are fluid balancer the way to go?

[jerry billet]

The twisting and vibration that a crankshaft can go through would tear your motor apart without one. If you look at a stock harmonic balancer you will see the outer ring is pressed on with a rubber gasket between them. This allows the outer ring to dampen the vibrations, hence its name.
Some of these may have large counter weights on them. for balancing purposes. Other crank shafts may be internaly balanced allowing the use of a balanced harmonic and flex plate.
the biggest diff in aftermaket is the containment of the outer ring. If you have ever had a stock style ring come apart, it can do some serious damage.
Jerry

[fourspeednup]

At what point do you think an aftermarket such as fluidamper is necessary?

[Hotcrusader76]

Anything up to 600-700HP should be fine with a GMPP dampner or better than stock set-up.
800HP and higher should look into an ATI version.
Throughout my research I've found that Fluidampners work great on my small-blocks and ATI's are great insurance for BBs.
If my memory serves me correctly, OTR lost it's dampner on that BBC 509 Merline. I don't remember the brand but it looked like a freaking grenade went off! Yikes!
~Ty

[fourspeednup]

Sounds like I'm safe then
-four(((doesn't like the idea of a grenade going off in his boat)))speed

[clownpuncher]

Originally posted by Hotcrusader76
If my memory serves me correctly, OTR lost it's dampner on that BBC 509 Merline. I don't remember the brand but it looked like a freaking grenade went off! Yikes!
~Ty
Correct. From what Wes was saying, the destruction of the balancer was the cause of the crank damage, which was also replaced. The broken balancer was replaced with a fluid dampner. So far no problems. I beleive Infomaniac supplied my new piece. He'll definatley be able to give you a better answer as to which way to go. My amature opinion is get the best one available. The higher cost will be greatly offset by NOT having to replace a crank, or worse.

[shaun]

I'm building a BBC 454 and the hermonic ballancer i took off of it was from a junk yard. it looks kinda beat. What would you guys recommend? Motor will probably be running 10:1 compression, 990 heads with some head work and a decient cam. I dont know what hp numbers to expect.

[Chris J]

RPM is the biggest killer of stock dampers, If you plan to run over 5500rpm you should start thinking about aftermarket. Look for one that meets SFI spec 18.1. Most have 360 degree timing marks which is nice for setting valve lash and full advance on your dist. (the only timing that matters).

[JetBoatRich]

I had an incident last year where my engine broke the "KEY" and spun the balancer. It happened after years of use, but make sure you buy a quality part.

[jstwkd]

If anyone is interested I have a brand new internally balanced fliudamper for a BBC. Never used it . Ended up going ext. Balanced .Make me an offer.