Thread: Fluid damper vs harmonic balancer

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Please educate me on the difference and which one to go with. for chevy 454 Now that I have looked into flexplate I see prices from $50. to over $200. what shoud I be looking for?

Not much to figure out, just go to the website and look up the motor. I will say this the Fluid damper is a great product. The timing after installed seemed and felt more precise, motor hits harder.


454: have a look here see if it helps ya.

Chevy Big Block

In my last 20 years as an NHRA techinspector, I saw many Fluidampers used on drag race motors. I'd use the largest diameter unit I could bolt on the crank, like the 800111 with eccentric weight to match up with the eccentric weight on the flexplate/flywheel.

The other option is to use a factory OEM unit that has been rebuilt. Damper Doctor disassembles OEM units and uses new elastomeric material between the hub and the inertia ring, clocked properly for precision ignition timing and pressed together under tremendous hydraulic pressure. Here's their phone number, call 'em up and talk with them about availability and price.
Contact Us

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Ok so should I buy a Fluid Damper and a flexplate at the same time or how do you make them?match, Now that I have looked into flexplates I see prices from$50. to $200. which one should I be looking at?

Not positive on this, but I believe only early 454's are externally balanced which means the dampner and flexplate have to match.

Originally Posted by NTFDAY

Not positive on this, but I believe only early 454's are externally balanced which means the dampner and flexplate have to match.

all 454 from gm came with external all years. not the same damper for all of them mark 4 over the years are the same till gen 6 454. 90and up need more on the fly wheel weight and some times come up less weight on the damper and needs to be reworked as some gen 6 454 have a reluctor wheel on crank and gets sandwich in so the over all damper hub is shorter . on dampers i throw old 454 dampers out there is no way i send one out for a rebuild with seal cut on hub . as new there priced right on all new. save that rebuild bul% $hit for a something that can not be found any more . i seen to many beat with a hammer or outer ring with dents in then helcoils and speed sleeves. seen them fail. on some old cast iron parts in a stock damper screw that. on low buck build s i use oem pioneer .i used them no bad feed back and used many. i buy new dampers for engine i build so its not hard to buy over 20 a year. stuff that gets beat the hell out of for street pioneer sfi steel damper .i stop using fluldampr long ago all my big HP builds i use only ATI oh do not forget to check your press and may need to be hone for the right press as race dampers this need to be checked . this can only be done with the right tooling and not a brake hone . a machine shop with sunnen tooling with the CR series mandrel can do this job

Originally Posted by tominiowa

Ok so should I buy a Fluid Damper and a flexplate at the same time or how do you make them?match, Now that I have looked into flexplates I see prices from$50. to $200. which one should I be looking at?

there s no real way other then do what i do balance it. but it not a easy deal with fluidampr as some came with no hub to take off the outer ring to spin just the hub with counter weight .i have had them this way.but for a time they did not make them this way .i seen the fly wheel weight not come in right so if hi rmp engine it should be re balanced with part your going to use but if there no hub on the damper running the hole damper on the balancing machine it can make the machine hunt

I won't use a fluid dampner on anything---besides the balancing issues--down the road a bit---like on a race car--hit the wall or even just touch the wheel to wheel with another car--it will cause the weight to move in the fluid and guarantee a broken crank shaft within 2 weks---------this can also happen from spinning the wheels and getting sudden traction and/or even an overly aggressive downshift-----------

Originally Posted by jerry clayton

I won't use a fluid dampner on anything---besides the balancing issues--down the road a bit---like on a race car--hit the wall or even just touch the wheel to wheel with another car--it will cause the weight to move in the fluid and guarantee a broken crank shaft within 2 weks---------this can also happen from spinning the wheels and getting sudden traction and/or even an overly aggressive downshift-----------

them things fly... them ufo.s over the nascar field and hit cars out in the parking lot . that and great way to check the crank nose

I have a friend who had a blown 468 break the crank snout twice and the machinist said it was due to his fluidampr. He removed it and went to a drive hub with his new crank and he never had another issue. I've also had a couple high rpm 12v 5.9's break cranks at the first journal with fluidampr's. This only happened when a tcase blew up and the engine flared past 5500. The extra weight and inertia of the fluidampr was the only thing we could see that would cause that. We switched to ATI after that.

I thought I wanted a Fluidampner too (and bought one for my Big Block build)-after much consternation (and advise from my Engine Builder), I bought the ATI Superdampner for my 540 (it was cheaper than the Fluidampner to boot)-

Here's another vote for the ATI-

Well how do you choose a flex plate ?

Originally Posted by tominiowa

Well how do you choose a flex plate ?

what year do you have ? like i said i seen were a 168 tooth for a mark 4 or mark IV bbc 1970to 89 were the weight was off from brand to brand and like i said if you have a bbc VI or VI so here is some flex numbers mark IV scat SFI scafp-454 sfi .sfi pioneer pio871003 scat V VI scafp-454l-sl ATI damper ati917740 or or street/'strip damper power bond SFI pbbpb1018-ss motor state part number as the ATI damper is small then the stock damper 8inchs ATI is 7.074 you will need a new billet timing pointer like allstar all90022 or ati ati918958 like i said the press needs to be check and honed for the right press fit on crank this can not be over looked . if you need Tech on this or want to be sure you get the right parts first time i am dealer for ATI .TCI . BHJ. Power bond . Romac . McCarthy Performance / Racing Engines to 632+ Cubes

I am building a genIV 454, .060 over 9.3:1 compression, with 781 heads that were mildly ported and oversize valves installed, basically 400/435 HP will be running a Th-400 I do have a BHJ balancer. just need recommendation for a flexplate.

Originally Posted by tominiowa

I am building a genIV 454, .060 over 9.3:1 compression, with 781 heads that were mildly ported and oversize valves installed, basically 400/435 HP will be running a Th-400 I do have a BHJ balancer. just need recommendation for a flexplate.

Tom,
If you look at some of the performance tranny places they seem to offer either OEM or "Heavy Duty" flexplates (any link here is added by some outside program), and their HD units are in the $90 range. In the HP range you're running I'd be comfortable choosing a mid-range HD unit from someone like Summit, Jegs, or if you prefer, from a tranny place like Monster Transmissions who package them together every day. Just my $0.02 from a layman's view.