Inliners International Forums General Discussion Engines Damper (H/B): how to choose the right one?

Hi!

I was searching over the internet and read many different things about damper (harmonic balancers). Now, I noticed that I don't know how to choose the right one for my application.
My engine is a Chevy 250 stock and had its pulley slipped one time, but it was the 78' stock damper - I was not reving too much, just 5000rpm. :p
Now that I will do some work at the engine (cam, head work, valves, lifters, etc.) I have to choose a damper to fit its performance.
I'm interested in a Cat Power Engine Parts HBF350 Cat Power one. I start my search at eBay, because I'm brazilian and I bought many things from the US using it. I'll check performance warehouses too later.
Anyway... It's a fluid damper, not an elastomer damper - since I read it's best from idle to high rev engine speeds. I will rev 6000-6200 at this moment. But who knows?? The problem is that my car has a 2-grove stock pulley h/b (that with rubber)for Air-conditioning and I don't know if this new will fit.
And another doubt is if it's possible to groove at a machine shop the 2 grooves for the belts in a fluid damper pulley?
I'm sure the degree marks won't match, so I'll have to do new ones - don't see the marks at the eBay photo anyway.
The other question is how the diameter, thickness and weight affects its work?
I read that fisher one is used, and also about 8" ones... But my case is a stock crankshaft, pistons and rods applications. So, maybe this one I found for sale at eBay fit my needs. It's a 6 1/4" diameter, 2.420" thickness and 9.1 lbs weight.
Maybe a machine shop work to align to the other pulleys will be needed too...

Anything that goes out of stock need some thinking and planning... For me, that live in Brazil and have to buy without see and wait one-two months the parts to come is very complicated though.

That's why I am saking your help again.

How to choose a damper?

Thanks a lot guys!

If you check past posting here; Hank, Larry or both talked about these a while back.

Good luck.

Hi!
Well, I did the research here but didn't found what I was looking for.
Thanks!

Hi!
One thing I discovered searching over the fluidampr website is that a typical damper with an 8" diameter will almost always be more effective at reducing torsional twisting than a 6" damper, simply because the 8" damper has a greater inertia mass.
Another thing I discovered is that each kind of damper works in a different range of rpms.
I also read at Leo Santucci's book that L6 (250 and 292 for an example) have more needs to a damper than V8 ones beacause of their bigger crankshat.
So, I think I'll go with a 8" fluidampr to use in my 250. And the marks I'll do later. Just still don't know about the 2-grooves...
Anyway, thanks!

i don't think fluidamper makes one for our application (with 2 grooves).
do you have room to extend the waterpump and alternator pulley? to run a standard V8 one you will need to do that.
i would tell you to take a good quality V8 (standard type) damper and groove it at a local machine shop for the belts. also do your own timing marks.
tom

After market Dampeners DO NOT have any pulley grooves For Our L6s. OTHER then the One from fisher. It is ok for daily drivers BUT not for Racing Or HIGH rpms.It's not big enough. The one they have with the grooves Is a 6 3/4????? Or something like that.

With most aftermarket dampeners, you will need to bolt pulleys to the front and space out the waterpump, alternator etc to match. With some vehicles, such as an early Chevy II, space between the radiator and the motor becomes an issue.

While many here like heavier dampeners such as the larger Fluidamper, I lost two crankshafts with them. Have had great luck with an aluminum Romac balancer and a Reactor flexplate. Have made it through an entire season of racing with out either end coming loose, which never happened with a Fluidamper.

I have had success using the 8 in. damper for a 350 v8. I have tried the 250 and 292 dampers. They would not last long at all. I am running a 292 at 6000 rpm's in a pulling tractor. The 8 in. damper has lasted for over 2 years. Hope this helps.

Bruce,

I was wondering where you can buy the Reactor flexplate? Price???

Can it be used for street use?

BTW,,,,ditto on what Hud I said,I ran a 8" SBC damper w/goodluck.
Thanks

MBHD