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I bought a fluid street damper from Flatlander( CAT brand) for my 351/393.It does not have the removable counterweight.Now somebody told me the engine cannot be balanced with it due to the silicone fluid containing outer ring.
If it is so what to do? Can I have the engine balanced with an untouched 351W rubber damper and just simply bolt the fluiddamper on during assembly?
 

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This is from Fluidampr's tech FAQ's. "When the Fluidampr is balanced with the assembly, it is necessary to separate the ring from the counterweight and balance the Fluidampr with the counterweight portion only. After balancing is complete, reattach the ring".

If you have a one piece damper that won't come apart I would recommend that you get something else so you can balance it with your motor.
 

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Also from Fluidampr's site are instructions on balancing if you are using their "Streetdampr". They say for their silicone dampener with non-removable counterweights to use a stock OEM dampener for the dynamic balancing, then swap to the silicone.
 

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The damper with non removable weights is for engines that are INTERNALLY BALANCED ONLY!In other words the assembly is balanced to "0" without the damper on it then it is placed on afterwards.If your old damper has a counterweight on it...then your engine isnt internally balanced.
 

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R-Code is correct here.

Neutral balanced engines have no extra bob-weights on the balancer and flywheel. None of the small block fords are neutral balanced from the factory. They have extra bob-weights on their externals to help balance the rotating assembly.

Aftermarket balancers and flywheels need these bob-weights as well. Silicone filled harmonic dampners don't work on balance machines. This isn't a problem on the "race" Fluidamprs because the silicone filled inertia ring unbolts, but their cheaper street-dampr and the CAT unit don't have removable silicone rings, so a replacement harmonic dampr must be substituted during the spin-balance job at the machine shop.

Good Luck!
 

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Well said Mike. If I had done a better job with my post we wouldn't have had the confusion.
 

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Yes ... N2O and R Code got it ...

I encountered this precise issue on my 351C build ... I read the instructions in the package and realized the balanceing issue ...

I concluded that I needed to move up to the "Fluidampr" and did so ... I received the "Streetdampr" because my sales person at Jegs made a (Judgement call / Mistake) or what ever ...

Anyway these two guys have it exactly correct.

Streetdamper is more for the guy that wants "High Tech" damping, but Ain't pulling things apart to rebalance ... or just can't put the $$$ together for the upgrade to "Fluidampr"


also ... I was dealing with the actual "Fluidampr" brand ... not CAT or anything else.

_________________

Larry Madsen
Las Vegas Nevada



<font size=-1>[ This Message was edited by: monstermach on 2/12/02 6:37am ]</font>
 

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Discussion Starter #8
Ok, I quess it would be ok to borrow the counterweight from my friend´s Fluiddamper, balance the 393 with it and then bolt on the CAT streetdamper? BTW any experiences abt the CAT brand? Unknown to me... except it has something to do with Caterpillar...
 

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Well I stand by my recommendation. If you've ever looked at your damper after a balance job you will likely see the drill holes in the back of the inertia ring where they took weight out or added weight or moved weight around. The balance process creates a completely custom package that includes the crank, rods, pistons, flexplate/flywheel and damper all together as a unit. The 28.2 or 50 ounce thing is just a starting point and gets modified in the balance process. This is why the balance shop wants your specific damper and flexplate/flywheel to start with.

If you balance your motor with a conventional damper and the balance shop has to touch the damper at all which is likely with your stroker setup then when you slide your non-modified street damper on there the motor won't be in balance any more.


<font size=-1>[ This Message was edited by: Hottarod on 2/13/02 2:42pm ]</font>
 

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A GOOD balance shop will not take weight out of the harmonic dampener or flywheel. They take it out of the crank. This makes it possible to swap dampeners/flywheels at a later date without screwing the balance up too much.

Yes, not every factory harmonic dampener is exactly the same. I've seen them drilled before. I believe they come that way from the factory. When balancing out to 1/2 gram precision, it pays to have all the parts that are going to be used in that very engine... including the clutch pressure plate. Ideally, the rest of rotating assembly is done first, then the pressure plate is added, and it is ground on to be brought to neutral balance.

With a non spin balance-able harmonic dampener like the Street-Dampener or the CAT unit, the best bet is to use a good quality aftermarket unit that hasn't ever been messed with as a replacement unit. The hub to a regular Fluidampr would be the best bet. That's what a friend of mine did on his Street-dampr equipped 406 Chevy.

Good Luck!
 
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