Originally Posted by D-Man

I heard some issues about fluiddampers that caused me to steer clear of them and go with ATIs


here goes some of the stuff I heard...this is coming from the Scat Crankshaft website

A word about vibration dampers
In our conversation, Tom Lieb gave us some great (though sure to be controversial) information about a subject directly related to the crankshaft and its survival in a race engine: vibration dampers. He was quick to point out that a very common cause of crankshaft failure is using the wrong damper, and is especially leery of any damper that has moving parts. "A damper is supposed to balance an engine. How can you do that when you have something moving on the damper?" Lieb went on to say "Any damper with moving parts, whether it is fluid or mechanical, is not recommended in a drag race engine. Anything that moves in the damper has inertia. When you quickly accelerate or decelerate the engine, that moving part of the damper slams one way or another and puts a lot of stress on the crankshaft. For an engine that runs in a very narrow rpm band and with very little change in engine speed, like an 18-wheeler or a car that drives on the highway at a constant speed, a damper with moving parts is fine, because it will find the frequency at a constant rpm and dampen the vibrations. But with a drag race engine that accelerates and decelerates fiercely, the engine will only have certain vibrations for a millisecond." For a drag racing engine, Lieb recommends the lightest, smallest damper possible, with an elastomer-type construction. "The rubber will sit there and hum, but it won't change location

also another thing I found for a little trivia..

Fluidamper does suggest that it will take about 30 seconds or so on a cold day (below 30degF) to lower the viscosity of the fluid so the inner ring spins freely.

Originally Posted by D-Man

Here goes another quote from a guy talking about them....

"I work for a Caterpillar dealer and we have used fluid filled dampers for years in many different application, On highway and Off Highway trucks, numerous vehicular applications such as trains, Machines(dozers excavators loaders etc.) and industrial engines(EPG, gas compressors, drilling rigs and so on). Some of the larger engines actually use twin dampers bolted together. Anyway to the point a fluid filled damper has an iternal ring that moves within the fluid, This is what absorbs the harmonics from the crankshaft. Fluid by its self can not absorb harmonics, If anything fluid would amplify them. I do know that with the larger units over time the silicon fluid will gell up and cause the damper to become ineffective. Also dont use one with any external damage, The internal ring may be lodged by a dent in the housing thus not being able to dampen harmonics. If you do decide to run one make sure you buy a quality unit. I felt that on an engine that constantly is changing speeds that a fluid damper is not as effective due to the viscosity of the fluid changing with temperature. As the damper absorbs vibration it will heat up causing a different rate of dampening, I feel that if the engine is not changing speeds as often it would be fine. Think of a fluid damper as a hydraulic shock absorber, The more you work it the shorter life span the shock has. Face it oils/fluids have a certain life expectancy and if you heat cycle them enough they loose effectiveness by breaking down. So for long term and durability I say an elastomer damper is the best choice, But the fluid damper I feel has superior dampening qaulities. So with that said its up to you, You arent going to put it on and have the snout of the crank break from it, And if you do it would more than likely have broken no matter what balancer you used."