[540neverdone]

On my 540 build, I asked for internal balancing so rotating assembly parts were balanced by the machininst prior to my recieving them. This engine is to have a manual trans behind it, no pressure plate has been ordered yet. Can anyone recommend a balancer for this internally balanced street/strip motor?

Considering the one in the thumbnail, here is its description:
Certified to SFI 18.1 specs, Professional Products degree'd 8-inch-od damper is a quality racing unit at a reasonable price. Bolt-in counterweights permit the same basic balancer configuration to fit many engines. This internally balanced motor uses a neutral-balanced version.

[Deez]

Don't think that all harmonic dampers are 'all of that' because it has the SFI deal. Some engine builders will not use the PP dampers at all having had issues with them separating. There are many others though who have had good success with them. The BHJ site has some really good tech if you care to look. Fluidampr info here. ATI damper link info at the bottom of this page . Depending on where your engine will spend the majority of its time (RPM) will be a factor in your final choice. Some top shelf units are quite pricey, and some of them won't fit the bill if your RPM range is lower or higher than the damper is 'tuned' for (some don't really do much until over 5000RPM). There are as many different views and opinions as there are answers to which one is right for you. Hope this helps.

[540neverdone]

But how come different balancers sold for the same size engines with the same type of balancing come in different diameters like 8", 71/4", 6" just as examples.

[Deez]

The way I always understood the diameter thing was like this, smaller seems to fit the guys who think it will let the engine rev faster, bigger for the guy who doesn't care about the 5 or 10 HP but. To me, the bigger diameter has more mass to absorb unwanted harmonics. The downside is there could be issue with too bog for a given application. I do not, nor have I used the fluid type dampers. If you read the tech stuff it explains pretty much all you need to know. Best thing for you would be find one same stock diameter w/neutral balance. How much you going to spend? I once bought an 8" PP for sbc but after reading some failure stuff never used it. Might use it on a mild mannered 406 though.

[cobalt327]

You tend to see the larger OEM dampers used in apps where more torsional forces are expected, like high performance, larger engine, truck, etc.

Some of the 283 dampers are down right tiny, IIRC, some were solid.

From what I read several years ago, dampers like the "Rattler" were thought to be about the best compromise. This may well have changed since then.

[Deez]

Most damper companies tout theirs as being best. But, their is only one true 'best' one, and that would be one made and tuned for your specific application. The bonded elastomer design works great. Heat is one drawback to the design which might be why some fail. I would think with today's materials there would be an elastomer design and material that could take the heat generated by a working damper. It seems not to be the case on occasion, where the things separate. I think though, the dampers were not correctly chosen for the application in those cases, or one was chosen as a fitzall and it did not work.

[BBCMudbogger]

I have a pioneer balancer I think it was about $100-120 and is a nice piece.

[oldbogie]

Originally Posted by 540neverdone

On my 540 build, I asked for internal balancing so rotating assembly parts were balanced by the machininst prior to my recieving them. This engine is to have a manual trans behind it, no pressure plate has been ordered yet. Can anyone recommend a balancer for this internally balanced street/strip motor?

Considering the one in the thumbnail, here is its description:
Certified to SFI 18.1 specs, Professional Products degree'd 8-inch-od damper is a quality racing unit at a reasonable price. Bolt-in counterweights permit the same basic balancer configuration to fit many engines. This internally balanced motor uses a neutral-balanced version.

The first decision is how this engine is getting used, street, in combination with strip, short track, long track. What is the RPM range, both where it spends most of its time and max.

Next is what is the crank made of?
- Cast iron does a lot of self damping, but at the same time is more given to fatigue failures than steel. So it needs better damping than one is usually lead to believe.

- Cast steel is a bit stiffer than iron, it has pretty good self damping properties like cast iron and has greater resistance to fatigue. It is more tolerant of somewhat less damping.

- Forged or billet steel has little self damping but great fatigue resistance. It needs a pretty good damper as it will bend thru the number one main and carve the bearing out which will fail oil pressure to the first rod journal.

Dampers vary in size for both spatial fit and frequency difference. Engines operating at different RPMs and loading, and with different crank materials need different frequencies damped.

Dampers come in three basic varieties:

1) Bonded rubber; consisting of a hub and outer mass ring bonded together using rubber. The amount of damping and the frequencies damped are controlled by the mass ring and the stiffness of the rubber. These are a factory favorite because they are inexpensive to make and are quite effective.

2) This is a variation on number one the ATI units being typical where the mass ring and hub are separated by rubber O rings. These are rebuild-able and tunable.

3) The silicon fluid filled damper typical of Fluidamper's products. The hub and mass ring are enclosed with a leak tight container filled with a heat sensitive silicon fluid. These are the most flexible to use because the fluid changes viscosity with temperature. The action occurring between the hub and the damper ring makes the fluid change temperature getting hotter when greater amplitudes and or frequencies are encountered and cooler when amounts of movement and frequencies lessen. This causes the fluid to change viscosity which proportionally changes the amount of damping. These things are expensive and of course are prone to leakage, but when they work there's nothing like 'em.

All types of dampers are less effective when the engine is cold.

The last consideration is safety, high RPMs and certainly racing organizations require that these things meet explosion resistance requirements. Except in some lower stock classes, OEM dampers are not permitted on the track for very good reasons. Let this be your RPM guide.

Lots of purveyors of dampers like to sell their's on the basis of gained horsepower. Forget that, the goal of the damper is to remove unresolved vibrations on the end of the crank. The true result of insufficient damping will be either a failure of the crank snout as it will break off; or a lubrication failure caused by the unresolved forces causing the crank to run off center in the number 1 main. The latter failure carves out the bearing in the front to rear direction resulting in the loss of oil pressure, this quickly takes the rods running on the number one crank throw. Ask my how I know!

Bogie

[540neverdone]

Thanks boogie! a very well written and thought out response. I apologize if I did not mention in the original post that this was for a 6spd manual, street strip car. 67 Camaro to be exact. Mainly a street overkill motor. (With a first gen Camaro you gotta do a little extra to stand out from all the rest) The cam is a solid roller, with this many cubes its not a high RPM screamer, do you think the balancer I suggested for this use would fit your recomendation for this build boogie?
Thank you for all responses.

[cobalt327]

It would seem (intuitively) that a cast crank would be less "self-damped" as compared to forged. I think of cast iron as being fairly stiff, but "brittle" and forged the opposite- so more able to damp itself.

Thanks for the clarification.

[540neverdone]

This is a forged crank as you may have imagined. Cobalt I thought as well from metal work that forged is more maliable than a cast "Brittle" metal.

[ericnova72]

The cast material has more dampening because of the "loose" molecular dispersal that comes from the casting process itself. This is easily displayed in the fact that a forged crank will ring when struck with a hammer while the cast crank emits a muffled thud. Shocks don't travel through the material from end to end. Don't mistake malleability and ductility with dampening. A forged peice will transfer a shock load from one end to the other virtually unchanged.

[540neverdone]

Like a tuning fork! I sure don't want an E-flat!
Get it, E=Engine? ................................

[540neverdone]

Does anyone have any thoughts on the balancer I included in the OP? From expirience or not?