Ok I need some answers to the fluid damper controversy. I’ve heard it breaks cranks and other problems, I’d like to hear first hand experiences not he said she said answers. Also if problems, the reasons? Thanks before I put this on the Hemi

I have had mine on for 20yrs

I've had mine for 18 yrs. Have ran it on two cars and never an issue.

I ran one on various stroker motors for at least 20 years until I finally switched to ATI. Never had an issue. There are a few people on the internet who swear that they cause problems but I've never seen an issue with them. They really are designed for lower rpm engines so perhaps might be a better fit for a stroker motor than a high winding drag race car.

They are basically a mechanical tuning item, and each motor/application has different needs, each damper has a different optimum rpm range, some chose poorly.

ATI online has a posted graph that displays this fairly well, IMO

I was waiting for you two guys to answer. 4.15 crank on a 4 speed street engine. I have all three, ATI, BHJ and FLUID DAMPER I like the FD because it’s thick like the stock one but recessed to use the 440 pully

Too much harmonics with Fluidamper.. Bearings always looked schmeary . Switched to ATI. Never an issue again.

If you have a FD damper on hand that fits your application then I'd use it. It should work just fine with a 4.15 stroke street engine. I wouldn't use a FD on a circle track engine or a high winding drag engine but a stroker street engine should be just fine. FD are really designed for diesel engines and truck engines and such but they seem to work okay on passenger cars too. I think it is very important to have the rotating assembly properly balanced regardless of which damper you use.

My 572 has had a Fluid Dampner going into its 8th year, 650 passes. Bearings have been fine. The rod bearings have well over 350 passes. At last check looked like new. And I bought it used.
Doug

I think early on after Fluid dampers first came out after NHRA mandated the use of them in some classes some guys broke cranks and blamed that on the dampener being revved up when the outside air temps where below freezing
Maybe they had cracks in their cranks before switching

The bearings that came with the crank looked blackened but no other blemishes and the crank checked out great. Was in a race engine (world block). He was going to a 4.5. crank

I shifted as high as 8800 with a fluidamper on OE cranks and never broke a crank and the bearing looked perfect. They are not low RPM dampers.

I've had one since they first came out. 30yrs?......doesn't have the recess for the crank pulley. three different engines and never saw any negative bearing wear. stock stroke to 4.15 and max rpm of 7500.
ATI's own graph even shows them to be the better choice up to a certain RPM.
They are heavier than ATI's, but that might even be a plus.....although the initial rotating mass portion may be lighter than ATI's?

I ran one on my race engine that was turning 8200 rpm and one still on my street rod
thats a 7300 rpm 416 stroker.. I have never had any issue.. both of those are using a
motor plate and I dont feel anything weird

20 plus years 4 different engines

RPM isn't directly a factor.
The question is: will the engine operate at a higher RPM which includes another destructive harmonic order? If yes, the damper design is different.
Mistakes from 50 years ago: Ford 289 210 hp owners install high-perf 271 hp and Cobra parts, including the cam. The 210 hp low-perf damper does nothing above 5,000, the 271 cam works above that. Wrong damper: broken crank.

Poly.. was that the fault of the balancer or the fault of the crank or design of the engine and
would newer say 20 year old work.. I've been running them for a few years

The 271 has a different damper, which suppresses harmonics in the higher RPM range.

And my vibration went away instantly when I went with ATI..........

Seems like crankshaft manufacturers don't like the fluid dampers too much.