Harmonic Damper & Balancer Questions

[Ranz1]

What is the purpose of both? Does price (cheap stuff) affect the function/purpose of the balancer? Are fluid balancer the way to go?

[jerry billet]

The twisting and vibration that a crankshaft can go through would tear your motor apart without one. If you look at a stock harmonic balancer you will see the outer ring is pressed on with a rubber gasket between them. This allows the outer ring to dampen the vibrations, hence its name.
Some of these may have large counter weights on them. for balancing purposes. Other crank shafts may be internaly balanced allowing the use of a balanced harmonic and flex plate.
the biggest diff in aftermaket is the containment of the outer ring. If you have ever had a stock style ring come apart, it can do some serious damage.
Jerry

[fourspeednup]

At what point do you think an aftermarket such as fluidamper is necessary?

[Hotcrusader76]

Anything up to 600-700HP should be fine with a GMPP dampner or better than stock set-up.
800HP and higher should look into an ATI version.
Throughout my research I've found that Fluidampners work great on my small-blocks and ATI's are great insurance for BBs.
If my memory serves me correctly, OTR lost it's dampner on that BBC 509 Merline. I don't remember the brand but it looked like a freaking grenade went off! Yikes!
~Ty

[fourspeednup]

Sounds like I'm safe then:cool:
-four(((doesn't like the idea of a grenade going off in his boat)))speed

[clownpuncher]

Originally posted by Hotcrusader76
If my memory serves me correctly, OTR lost it's dampner on that BBC 509 Merline. I don't remember the brand but it looked like a freaking grenade went off! Yikes!
~Ty
Correct. From what Wes was saying, the destruction of the balancer was the cause of the crank damage, which was also replaced. The broken balancer was replaced with a fluid dampner. So far no problems. I beleive Infomaniac supplied my new piece. He'll definatley be able to give you a better answer as to which way to go. My amature opinion is get the best one available. The higher cost will be greatly offset by NOT having to replace a crank, or worse.

[shaun]

I'm building a BBC 454 and the hermonic ballancer i took off of it was from a junk yard. it looks kinda beat. What would you guys recommend? Motor will probably be running 10:1 compression, 990 heads with some head work and a decient cam. I dont know what hp numbers to expect.

[Chris J]

RPM is the biggest killer of stock dampers, If you plan to run over 5500rpm you should start thinking about aftermarket. Look for one that meets SFI spec 18.1. Most have 360 degree timing marks which is nice for setting valve lash and full advance on your dist. (the only timing that matters).

[JetBoatRich]

I had an incident last year where my engine broke the "KEY" and spun the balancer. It happened after years of use, but make sure you buy a quality part.

[jstwkd]

If anyone is interested I have a brand new internally balanced fliudamper for a BBC. Never used it . Ended up going ext. Balanced .Make me an offer.

[superdave013]

Originally posted by clownpuncher
Correct. From what Wes was saying, the destruction of the balancer was the cause of the crank damage, which was also replaced. The broken balancer was replaced with a fluid dampner. So far no problems. I beleive Infomaniac supplied my new piece. He'll definatley be able to give you a better answer as to which way to go. My amature opinion is get the best one available. The higher cost will be greatly offset by NOT having to replace a crank, or worse.
Guys, read the above. This was not an 8,000 rpm fire breather. I know it's a stout deal but like I said. Not a super high rpm runner. Not only did the balancer let go but it took out the crank too! OUCH!!!
If you are building an new engine some of the BEST money you can spend is on an SFI approved balancer. ATI, BHJ, Fluid Damper and many others are up to the task. I would say that if it's SFI certified it's a top notch part. Same for the flexplate / flywheel. Why not get a good one? I've never had a damper fail but I did toss the weights off a flexplate once. It shot out of the bell housing and even went through a 3/8" bolt. I got lucky it went up and not through the bottom of the boat.

[superdave013]

Originally posted by JetBoatRich
I had an incident last year where my engine broke the "KEY" and spun the balancer. It happened after years of use, but make sure you buy a quality part.
Blown engine with only a single key = NOT GOOD
Double key that stuff man.

[Rexone]

I've had stock balancers come apart in "stock" applications. Results = not good. Don't shortcut this stuff.

[Blown 472]

Originally posted by superdave013
Blown engine with only a single key = NOT GOOD
Double key that stuff man.
Blown chivvy with whimpy little key not good.
Blown mopar over 650 hp, shifting at 6500 rpm with just a hub and no problems so far, knock on wood.

[CrdStang]

I know it aint a "jet boat", but here goes anyway.
Coughed up the cash for a SFI approved dampner after noticing the outer ring on my stock one was about 1/2" away from flying off my street car. Scary!
I coughed up around $100 for an ebay fluid-type dampner.
Here's the kicker though, the engine ran NOTICEABLY smoother with the good dampner. I felt the difference immediately. If you can feel it from the seat, imagine how much difference there must be for the engine..
These days I make a habit of checking the dampner on any engine I deal with. If the rubber between the outer ring and the hub is old and cracked, get that thing outta there ASAP.
Mike

[Chris J]

If it is a stock or mild motor the $250 for a SFI balancer could be use to have the motor balanced. Just a though, instead of speeding money to offset in-balance in the motor why not balance the motor first. You still would want to replace any damaged or worn stock balancer. And I'd still recommend a SFI one on a Hi pro or race motor.
Most damper failures in stock applications are due to worn damper or internal motor problems.

[LVjetboy]

A balancer or dampener does not dampen an out-of-balance engine. It's function is to dampen torsional vibration only. In fact, if you get a new fluid dampener and your engine's externally balanced, you may need to rebalance the assemply with the fluid dampeners counter weight only (ring removed).
jer

[shaun]

After reading thru this thread a i feel i definitly need to do somthing about mine. I have a couple questions..
whats the diffrence between a balancer and dampaner and why would one run one of the other?
Whats the diffrence between a internal and external dampaner, what are the advantages/disadvanates to running one over the other?
Same questions about a fuild dampander/balancer.

[MANIC MECHANIC]

Shaun,
An internally balanced engine means the crankshaft is balanced
by removing or adding weight to the cranksaft counterbalance weights (the heavy flat appendages opposite each crank throw).
in an externally balanced engine although the crank still has the counterweights opposite each throw the imbalance is corrected by additional counterweights on the flywheel and harmonic balancer.(Which by the way adds additional stress to the crankshaft)
Due to the fact that no V configuration engine can be balanced perfectly a harmonic balancer is needed to dampen the remaining vibration.
Tim

[shaun]

Since my crank is stock i would assume ineed to run a external balanced hermonic balancer? Also, on the counter weights i noticed that they arnt all the same size, looks as if some of the corners have been ground away alittle bit. I figured this was a way they balanced the crank when it was made?

[LVjetboy]

Shaun,
A balancer and a dampener are terms used to refer to the same part. That big round thing on the front of the engine. Although "balancer" is not entirely correct it is used by those who don't understand the true function. The dampener may or may not have counter weights to help balance the engine, but the dampener's true function is to dampen torsional crankshaft vibration not to balance the rotating parts...as I said before.
Dampening torsional crankshaft vibration IS NOT THE SAME THING AS BALANCING the rotating assembly to reduce lateral vibration.
Copy?
I'm sure more than one crank destroyed by some backyard mechanic slappin' a fancy fluid dampener on his engine hoping it would "balance" the crank.
jer

[shaun]

I'm brining this one back up to the top...
I am going to purchase a damper and i need to do this ASAP since the machinest has my bock and cant balance it until i get him this peice.
Here's a couple i ran across on ebay. This is the first time i've done this stuff so info/input is always appriciated!
All of these say they are SFI.
Fluid Dampner #1 (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2476561838&category=33616)
Fluid Dampner #2 - Chrome *bling* (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2476729486&category=33616)
Steel Damper #3 (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2476729498&category=33616)
Dampner #4 (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2476734236&category=33616)
There is a hole bunch of them on ebay.