Inliners International Forums General Discussion Hi Performance Which balancer for a 250?

So I did a forum search for the word balancer... came up with 24 pages! I don't want to go through that!

I was wondering which balancer would be best for my 250? It will be mainly stock with the exception of the supercharger.

I read that a fluidamper is the best. The I read that a SBC 8" damper is the best. And on and on!

I need help from the experts! Or at least someone who has been through it already!

Best?
One designed specifically for that engine (very different from any V8), which is what it came with. If you want to spend more money, get an S.F.I.-18 compliant one from one of several manufacturers. Be prepared to spend money.

Glen recommended the ATI super damper with a # 88 durometer rubber, it cost $406 delivered. I think its cheap insurance for the cash I've already spent.

An SFI damper doesn't necessarily increase crankshaft life over the original - it's simply explosion-proof, hence safe for high RPM.
Frequent use of the wrong damper (8" V8, etc.) shows that any damper at all is better than completely worn out (no rubber, hardened rubber, bent, loose), but even the best only affects the crank in a few narrow RPM ranges.

When I called ATI this week, they said with RPM's below 6k, there's no reason to change rubber durometer. Personally I would run a Fluidampr for RPM's below 6k, but that is not based on any 6cyl specific knowledge. I have read about tests not on a 6 that showed below 6k the Fluidampr is hands down the best. If you spend time above 6k, I would go with an ATI. 2 cents given. Panic's points are valid. Even a new stock one will help quite a bit.

I think the original was designed the way it is because of the length of the six and being able to stuff it in a car. It just takes up less space with the pulleys on the outside versus in front, GM engineers didn't expect to see guys like us trying to make it do all the things it's not designed to do. Maybe the same reason for a one barrel, low RPM designed cam, you know how it works, engineers designed it to have studs and bean counters put bolts in it. I put studs back in mine and plan on trashing on it anytime I want to and not worry about it blowing up. My 2 cents also.Have fun with your Hot Rods !

Look @ Tlowes fluid damper get trashed (along w/the crankshaft) on the 250 dyno pulls. ouch!

I have heard of a fluid damper leak & the fluid get stuck on one side from sitting too long.Massive imbalance.

Not sure if there is any truth to those stories I heard.

I used to trash stock dampers all the time & chew up the crank snout a bit until I just decided to use a GM 8" HP damper.

Never had a problem w/vibes & engine totally smoothed out & was able to turn high RPM up to 7500. As compared to struggling to get to 5800-6000 RPM w/a stock 250 damper.


MBHD

Hank,
What is the part number of the balancer you run?

Don't have a P.N. for the particular one I used.

It was just a standard 300 HP 350 SBC. 1969-1970 4 barrel carb 10.1/4 to 1 compression.

Here is an example. http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=22982

Here is one that is supposed to be better for less $$.
http://www.jrmotorsports.com/product.cfm?InvKey=27964

GM performance should have them also.

My new engine will have a Vector damper on it.

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MBHD

Here is one on Ebay,there are more also.

http://cgi.ebay.com/ebaymotors/sb-sbc-Ch...sQ5fAccessories

MBHD

Hank

That looks like the Old Fisher dampener. If so the only draw back is. It starts to sling the lube out of them they would lock-up and stick. So my new motor got a ATI.

I never Used the fuild. I heard to many stories/issue with them
going out of wack. But I know a few you use them and haven't seem to had any problems. But most run the rpms below 6000.

I have lost two 292 crankshafts with Fluid dampners. Since changing to a Romac have not had any issues.

I have been thinking about dampners, why some work in certain cases but not in others.

Could be the difference is between cast and forged cranks , short and long strokes, high and lower RPM, automatics and sticks, or all of these different combinations.

Seems you need to find what works for your set up no pat answer.

I have always used 1963 292 forged steel cranks at about 6500 RPM, with a powerglide and a Fluid dampner.

An ATI did not work for my combo.

What are your combinations ?

Just food for thought.

Harry

Thats true Harry. Even an engine with very high compression might have different needs for dampening than a low compression street engine. So might a N/A engine versus a blown or nitrous engine.

Only 2 major factors in damper design:
1. what is the crank like, especially length, stroke, journal diameters (V8 and L6 are about as far apart as you can get, and 4 main vs. 7 main L6 are also very different)
2. how fast does it turn, specifically how many harmonic orders are inside its RPM range

How many miles did yours have on it before it got stuck?

It is a Vector damper,which used to be Fisher.
http://hotrod.automotive.com/66517/hrdp-0610-vector-damper/index.html
When I told Mike Kirby I bought this one,he wanted to buy it from me. So that tells me something.

I am thinking my new engine will turn to around 7500 RPMs.

MBHD

It wasn't so much the miles as i think it was the rpms.It would sling the lube out then it would stick.I used what (fisher) at that time told me to use. If I ran the rpms over 7000 it seemed to do it every time.So i was redoing it about every 3rd weekend of racing.I knew everytime it was getting dry the motor would shake or get ruff at idle or certin rpms i would feel the vibs.
But it was always a easy fix. I just got tired of having to deal with it.

Thanks Larry,
what exactly were you redoing to the damper?
Applying lube,what kind of lube?

MBHD

Relubing it.I'll have to see if i can find what i was useing, But I beleive it was a forum of moly lube,They said to be useing on it.(It wasn't just grease) But like i said I'll try an find it an let you know.

Is there any true advantage to running an 8" balancer vs the stock if your rpm range is less than 5500?

If yes, then where can the pulleys be found for the alt, water pump and balancer (junk yard or all custom made)?

Yes ,there is an advantage.
I would try to get an 6.3/4"-8"" damper & have a machine shop machine the "V" grove/s needed to drive your accessories.I am pretty sure that damper worked better than a stock one also.

Try the search feature to find it, I have no luck w/the search engine here,other forums I visit,no problems.

I think REVOD did this mod,somewhere in the old threads.
I think Revod did this type of mod to a 6.3/4 " damper same as stock size.
An 8" damper w/"V" groves will speed up your accessories as compared to your stock damper.

MBHD