More Harmonic Balancer questions
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From: South of giving a damn
St. Jude Donor '11, '17
More Harmonic Balancer questions
Norval has suggested that we don't need one, but his questions aside, how does one decide which size & weight to use? I see several options from 6" & 6lbs to 8" & 10lbs. Questions pertain to an internally balanced engine.
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
Originally Posted by ratflinger
Norval has suggested that we don't need one, but his questions aside, how does one decide which size & weight to use? I see several options from 6" & 6lbs to 8" & 10lbs. Questions pertain to an internally balanced engine.
I also have a 2005 5.3 V8 sitting on an engine stand outside my office and it has a very light simple harmonic balancer. A large hub and a thin pulley pressed on with rubber between it and the hub. It still is a form of harmonic balancer.
Drifting
Joined: Aug 2004
Posts: 1,883
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From: Lubbock TX
Quicker revving cars tend to like smaller balancers, one that's going to be making a lot of cruises/road trips will probably benefit from the inertia of a larger one. Stay away from anything with fluid in it, they're not what they're cracked up to be. As long as yours isn't built to the hilt, a stock 396/427 piece should be fine. Look at Pioneer, they're the best quality and priced stock ones I've found.
Le Mans Master
Joined: Sep 2001
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From: Unreconstructed, South Carolina
Primarily street ... NO fluid ... NO rattlers ... do use elastomer.
Guessing that internal small block 396 is 4.03 x 3.875 ... agree w/ L88Plus except you need one for a small block pre-85 350 ... Pioneer has 8" elastomer in std, HD & SFI (race-approved) ... if it's primarily street I'd go 8" and at least HD. Make certain you have a timing tab indicator that's configured for whatever diameter you end up with ... the tabs are different for the different diameters. Ideally, you'd install balancer & tab and index the timing mark before you install heads so that you can be certain of exactly where TDC is.
Guessing that internal small block 396 is 4.03 x 3.875 ... agree w/ L88Plus except you need one for a small block pre-85 350 ... Pioneer has 8" elastomer in std, HD & SFI (race-approved) ... if it's primarily street I'd go 8" and at least HD. Make certain you have a timing tab indicator that's configured for whatever diameter you end up with ... the tabs are different for the different diameters. Ideally, you'd install balancer & tab and index the timing mark before you install heads so that you can be certain of exactly where TDC is.
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I tried to find a good article. high end quality dampers are kind of like a lifetime purchase. My 6.250 SFI fluid damper is on my present 383 has been on many engines including a 9000 rpm dragster. My 427 has a 6 3/8th ATI SFI.
ATI's test show that their bigger diameters have better dampening qualities. I just preferr lighter weight.
Just a side note my 79 L-82 came equiped with one of GMs best models "8 inch" all it took was a few near 7000 rpm shifts in a shift kitted TH350 and it broke the rubber ring. Lucky it didn't come flying through the hood. This is when the 8 inch was only 2-3 years old and less than 20,000 miles. It taught me to use SFI rated products.
http://www.chevyhiperformance.com/te...nfo/index.html
ATI's test show that their bigger diameters have better dampening qualities. I just preferr lighter weight.
Just a side note my 79 L-82 came equiped with one of GMs best models "8 inch" all it took was a few near 7000 rpm shifts in a shift kitted TH350 and it broke the rubber ring. Lucky it didn't come flying through the hood. This is when the 8 inch was only 2-3 years old and less than 20,000 miles. It taught me to use SFI rated products.
http://www.chevyhiperformance.com/te...nfo/index.html
Race Director
Joined: Dec 1999
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Bigger is always better, fluid type dampers offer a larger efficient operating range than elastomer types, same for the pendulum type. Just get the largest SFI approved on that fits your burdget and that fits the engine.
I would think that the weight penalty is more than overcome by the superior dampening qualities.
I would think that the weight penalty is more than overcome by the superior dampening qualities.
Instructor
Joined: Dec 2002
Posts: 222
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From: Leander TX
Originally Posted by L88Plus
Stay away from anything with fluid in it, they're not what they're cracked up to be.
-Frank
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Drifting
Joined: Aug 2004
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From: Lubbock TX
Scat advises against using 'em on any of their 9000 series (cast) cranks - they had a lot of 'em breaking the snout off, same thing NASCAR engines did when they first tried 'em. Fluid is better at controling lower frequency harmonics but not so good at the top end. Fluid is dynamic UNLESS it's very cold at which point you may or may not be in balance until the fluid warms up.
My engine builder won't put one on even if the customer supplies it, he's been building 900+hp engines long enough for me to listen to him. I run what he recommends - ATI - on my higher hp stuff, stock type on stock rebuilds.
My engine builder won't put one on even if the customer supplies it, he's been building 900+hp engines long enough for me to listen to him. I run what he recommends - ATI - on my higher hp stuff, stock type on stock rebuilds.
Race Director
Joined: Dec 1999
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fluidampr says theirs is better at high rpm harmonics. You say "not in balance" .. the dampers (for int. bal. eng) are unbalanced and have nothing to do with engine balance, just with harmonics dampening. Also, since the fluid is viscous it would also warm up pretty fast after the engine is started, I don't really see how this could pose a problem. Maybe they're not as effective at lower rpm as the elastomer type, that would explain the scat recommendation since it's a cast steel crank they're talking about.
Pro
Joined: Jun 2005
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From: FL.
Originally Posted by ratflinger
Norval has suggested that we don't need one, but his questions aside, how does one decide which size & weight to use? I see several options from 6" & 6lbs to 8" & 10lbs. Questions pertain to an internally balanced engine.
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
I called Scat, Callies and Lunati today, all recommended any quality elastomer balancer over anything with fluid in it. I had to leave a message at Crower, hope to hear from them tomorrow. I know a lot of folks have had a lot of trouble free miles with fluid type balancers but I'm going to follow the advice of crank manufacturers and my engine builder.