This may be a dumb question, but here it is anyway... I need to go ahead and buy a new harmonic balancer for the small block chevrolet going in my shoebox...but now that I've started looking, I'm a little confused. It seems that there are all kinds of different diameters available, with 6.00" and 8.00" being the most common. I haven't checked to see what's on my motor currently (I'm at work as I type this) and I need a little help picking out the right one. What are the applications for the different diameter balancers? Is there a particular one that would work best in a street/strip environment? I will be using this on a '69 350 with a manual transmission that will be turning around 7000 rpm every now and then. Any recommendations as far as size, manufacturer, best value/price? Or will a stock replacement be OK? Thanks in advance for any help!
As a builder I would NEVER put a stock 2 piece balancer on a motor that has the ability to turn 7G. Do yuor self a favor and get an S.F.I. balancer for it. The Wizzard
Bass! I use FLUIDAMPER balancers on all of my engines. The TCI and ATI units are excellant also. Glenn
Does it need to be a 'name brand' even if it's SFI rated? The one I'm looking at right now is steel, SFI 18.1 rated, and 6.25" OD. The price is right, too...opinions? Thanks guys...
No, if it's SFI approved, it'll handle whatever you're gonna throw at it. A generic company wouldn't spend the major bucks to get an SFI cert.
Cool...so what's up with the different diameters? Is there any reason I can't use a 6.25" balancer on a motor originally equipped with an 8" balancer?
[ QUOTE ] Cool...so what's up with the different diameters? Is there any reason I can't use a 6.25" balancer on a motor originally equipped with an 8" balancer? [/ QUOTE ] As long as the balancer is made for the motor, you can run any size that is avaliable for that application.... I have heard (probably not all true) that some guys think that the motor turns easier with a smaller balancer... but who knows.... HC
The larger diameters are intended to work with the crankshaft harmonics of a larger motor. Smokey Yunick talks about this in his Power Secrets book. He said running a smaller balancer than necessary would risk cracking the crank over the long term. Of course,the harder you run the motor,the more likely it would happen.
I believe the higher HP motors came with the larger balancers. My '69 350 has the large balancer and I think it was listed for the '69 302 Z28 motor.
http://www.cnc-motorsports.com/category.asp?CtgID=9920 . Look at these Powerforce dampners from CNC. They also have non SFI versions. Shipping is $7.95 for all of the stuff they sell (even my stroker kit!!!). I have one for my SBF (non-SFI). So far it fits really good. Motor isnt in the car yet though...
The larger diameter matched to larger cubic inches/ more HP makes a lot of sense...thanks fellas. Afx - I was just checking out the Proform line of dampers on ebay...thanks for the link. I think I'm going to go with an SFI approved 8" elastomer-type steel damper. The Fluidampers sound pretty good, but I really can't justify the additional cost for a predominately street-bound motor. Anyone familiar with Pioneer brand harmonic balancers?
I am facing the same problem with putting a 350 in my 27. Front what I remember reading is that it depends on if the motor is externally or internally balanced and that the flexplate should match up as far as the weight. If running a older motor it looks like it should go with smaller balancer. I have not been totally convinced so I am still guessing. Just my 2 pennies.
Re: SBC Harmonic Balancer Question? Recommendation? [Re: a/fxcomet] #416729 - 05/25/04 10:32 PM Edit Reply Quote The larger diameter matched to larger cubic inches/ more HP makes a lot of sense...thanks fellas. Afx - I was just checking out the Proform line of dampers on ebay...thanks for the link. I think I'm going to go with an SFI approved 8" elastomer-type steel damper. You have made a good choice here. The larger the dia. the less G force on the outer rim and increases the ability to absorbe harmonics. The end result is a longer life for the rotating mass. The Wizzard
Brian, 30roadster was lookin for a rebuildable 327. Weren't you running one previously? You folks may want to work something out. Chris
my.02 for what its worth i tend to run the larger one on street motors the smaller ones race motors the smaller ones are nice if you have clearance issues fluidampner's are over rated and a waste of money, not to mention they are usually teetering on the brink of bankruptcy i was pleasently surprised with the qaulity of the professional products dampner, the price was good.workmanship looked great i was extremely concerned with a C.A.T.brand that was brought to me to install on a motor. a piece of crap.
RACEFAB, thanks for giving your opinion. I've heard the awesome small block in the BFD, and it's obvious you know your stuff...I appreciate the help! Crease, I've got a '72 350 in the shoebox right now, and there's really nothing wrong with it, so I'm going to put it on a stand for a future project. I considered going with a 327 this time for the large bore/short stroke, but the extra cubic inches won out. Nobody knows what it is unless you tell them anyway. Phil, the block went to the machine shop yesterday. I have to supply the balancer and flywheel for them to properly balance the rotating assembly, and that's what prompted the question. I'm going with a SFI approved Hays Billet Steel Flywheel on the other end, FWIW. A pretty radical small block has always been in the plans for the shoebox, and I'm finally getting around to it.
[ QUOTE ] I'm going with a SFI approved Hays Billet Steel Flywheel on the other end, FWIW. [/ QUOTE ] UH-OH!!! You said the B word!!! That should work just fine for ya, and I TOTALLY agree about the cubes thing. When I build a motor for my 55 I'm gonna build a BIG BBC (probably 600+ CID) and tell everyone it's a 427, then it's OK for a "gasser", right?
My .02 worth: I did a story once on TCI's Rattler dampers. No fluids inside, which I liked. No rubber or anything like regular dampers. All billet steel construction. I talked to an engineer there for a whole day, and looked through their papers and engineering notes, etc. The clincher was a guy who wasn't affiliated with them at the time (he later went to work for TCI) had a 6- cylinder that turned 9-grand plus in a Super Comp car. With every other damper he used, the torque converter would sonic weld intself to the end of the crank from the harmonics. Every time. After installing a Rattler, it never happened again. He also picked up a few hundred RPM on the top end with no other changes. Granted, I was touring their facility and talking with them about their product, but I've also seen the viscous fluid damper manufacturers, and of the two styles, I'd run a Rattler if I ever built an engine I was planning on racing, or just a big-inch, radical engine. (Can't really justify it on my $400 350 or my '56 Nailhead) -Brad
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