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Thread: Balancer vs. damper

  1. #1
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    Balancer vs. damper

    I'm starting a new thread on a topic the grew out of a discussion on UD pulleys and oil pump damage on Mach Is. As the discussion matured, it turned into a topic that needed some air of it's own. Here's the previous thread, if this is new to you it would be helpful to read here first.

    http://www.mercurymarauder.net/forum...ad.php?t=19325

    Here's where we left off;
    Quote Originally Posted by BillyGman
    As Cyclone03 had mentioned before, I think you're talking about two separate issues. DAMPENING, and BALANCING. Yes, they're both important, but they're not the same. In an internally balanced engine, the dampner is still needed, but it's only used for DAMPENING vibrations, which otherwise would travel through the crankshaft, and into other components such as the oil pump gears. The vibration Dampener isn't used, nor needed for balancing on an internally balanced engine, which is already balanced BEFORE the vibration dampener is installed.

    On an externally balanced engine, the engine internals are NOT completely balanced as an assembly until the flywheel, and vibration dampener are installed, because the dampener and the flywheel are both used to balance the crankshaft. As for heavier vibration dampeners being used on internally balanced engines, you're correct. The car manufactures are going with bigger and heavier vibration dampeners in Hi-perf applications, yes. But that has nothing to do with balancing needs. That has to do with the fact that lighter vibration dampners often do not absorb, or "dampen" the vibrations that run through the crankshaft as thoroughly (especially in a high RPM enviroment).

    Those vibrations are a normal occurance in any internal combustion engine, and will always be present regardless of whether or not the engine is balanced. The vibrations stem from the exerting force of the expanding fuel/air mixture upon the pistons during the compression stroke, which in turn is transfered to the connecting rods. This force being exerted on the connecting rods, causes them to flex, and therefore vibrate BIG TIME ( connecting rod "harmonics"). Those continual harmonic vibrations travel through the connecting rods, and into the crankshaft,and the crankshaft acts as a conductor of those vibrations. And w/out adequate dampening of this vibration via a vibration dampener attached to the crankshaft snout, the vibrations will not stop at the cranshaft, but will travel into other areas, and engine components will be destroyed, and eventually the engine will fail.

    As Mr. Reinhart has pointed out, some people have neglected to replace their vibration dampeners after they've removed them during the under drive pulley installation, and running any internal combustion engine in a street car w/out the use of a vibration dampener is an accident just waiting to happen. It's only a matter of time before the normally occuring vibrations produced by any engine will begin to destroy various engine components IF they aren't dampened, and it usually will not take very much time for that to happen either. But again, that has nothing to do with engine balancing. These are two separate issues (vibration dampening, & engine balancing).

    Greater care in precise engine balancing is taken during hi-perf engine assembly so that the reciprocting mass will run smoother, and will create less resistence to the force of internal combustion. That translates into more power. It's the same reason why serious drag race engines are built with lightweight aluminum connecting rods, and lightweight pistons. Less resistence= more power. But that hasn't anything to do with vibration dampening.
    Excellent post, Billy, thank you. I agree that I may be confused. I did a lot of engine building and drag racing 35 years ago, but only recently, since owning a Marauder, have I come back into the sport. I've had to catch up with a lot of newer technology that wasn't around when I was 20, some of which you younger gents take for granted today, such as automatic trannys, triple plate high stall torque converters, electronic computerized control over the entire driveline, and so on. I've been confused a number of times here, but I'm getting better at it.

    Right now, I'm confused on the difference between a crank mounted external balancer, and a harmonic damper, and I am confused, because I'm not finding the answers I expected. Billy says ^ there that they are two different issues, with two different resolutions. Others posted likewise comments in the previous thread, and I listened to all of them. However, this contradicts contemporary thought from the resources I researched in my learning update.

    Randy Crowley at PER, a professional race engine builder gave me my first lesson on this, that there are crankshafts that are internally balanced, and crankshafts that are externally balanced. I've seen the proof of that too, in the Ford Racing catalogue, and I'll come back to that later. Sean Hyland gave me my second lesson in his handbook for preparing the 4.6 and 5.4 mod motors for racing, identifying internal and external balance, and adding a third "neutral balance" in crankshaft technology for the 4.6/5.4 mod motor. Both professional men homoginized the topics which leads me to believe that the two different issues are no longer two different issues, and suggest some sort of hybird resolution in new technology. Here's my reasoning.

    The FRP catalogue has two pages of crankshafts to pick from. Page 72 has specs for 7 crankshafts, and only one of them is identified as internally balanced. On the next two pages, 74 and 75, are all the harmonic dampers FRP offers, and with grand variety. Choices include rubber, steel, billit aluminum, with or without internal hydraulic fluids, and one even includes removable weights for fine adjustment. But, my point is, there's not one balancer offered. Six crankshafts that will need an external balancer, but FRP offers none. But wait, there's more...

    I went to Summit on-line and did a few searches. The first was on crankshafts, and over 800 products came up. I paged through a few for specs, and concluded that about half are identified as externally balanced, and will need of an external balancer. Good, now I get to see what the new technology balancer looks like. So, I searched for balancer, and what does the search produce? Over 400 products returned under the heading of "harmonic damper". The search engine didn't produce any balancers, but offered harmonic dampers in it's place. Out of the first thirty products returned, only once did the word balancer appear, and that's an ARP bolt kit for the old technology.

    I did the same at Jegs, got basically the same results. The only time I saw the word balancer, was balancer accessories, such as bolts, hubs, and so on, as well as a few replacement parts for older engines, like AMC small blocks. Oh, BTW, there was a new product from Summit called a "torsional vibration absorber", WTF is that?

    I found dozens of harmonic balancers, and one balancer, what should I conclude? This is how I got confused, and I guess I am still confused now. Finding this while looking for answers, doesn't help.

    http://www.karkraft.com/46_damper.jpg

    The pic is "46_damper.jpg", the largest and heaviest damper on FMC parts shelves, but look what KarKraft calls it? (page down here)

    http://www.karkraft.com/modular_parts.htm

    My thanks to Billy and Lance for trying to set me straight, but actually, I don't think I was off track to begin with. It's my conclusion at this time, that what was once two seperate issues, share one solution today.

  2. #2
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  3. #3
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    Mac,please my friend take a break.

    In the world of Fords when most speak of Balancers what they are selling are in fact Dampers with an offset weight of some type.
    So in the case of Dampers vs Balancers they become the same in the parts catalogs. You will find in the FRPP catalogs the term 28in/oz balance and 50in/oz balance that is the "Balance Factor" of the base or stock engine.
    (The "older" 289,302 and 351w all used 28in/oz ,the "newer" 5.0l used 50in/oz.)If you held an example of each in your hand you could see the extra mass added to these "dampers" is offset to one side.
    These engines also use an offset weight in the(or on) the flywheel.
    These engines are known as "externaly balanced"

    Our Mod Motors do not use a "balancer" in that no "offset" weight is added to the damper/balancer or flywheel.
    If not for the Keyway on the crank you could just through it on without any indexing required and as long as it's tight the engine would run just as smooth as stock.If you could plug the big hole you could run the engine without a damper at all and the balance would be uneffected.
    Try that with your old 289 and the engine will shake like a paint mixer.
    BTW I have installed a 28in/oz balance factor flywheel on a 5.0l (50in/oz) engine and as soon as the engine idled I knew I screwed up!It's that noticable!

    In effect a Damper does just what the name implys.
    Billy hit the nail on the head in his post.

    I have heard several references made in the past relating crank shaft harmonics to musical instruments and tuning forks.
    The heavier fork vibrates at a lower(I hope) freqency than a lighter thiner fork.
    So by adding mass to the damper the freqency of the crankshaft can be "tuned".
    Being we seem to have mostly the same library as far as Fords go we know Hyland seems to like a heavier damper at high RPM.The guy has built a few high RPM Mod motors so I'm sure he knows what hes talking about.
    I have also read test (magazine) that some dampers release some power at high (6000-9000)rpm by stabilizing the cam timing and keeping the crankshaft in phase(all the throughs 90deg apart on a V8).The damper keeps the crank from "ringing"at speed keeping it strait.


    Mac if you want to see a few "extenally"balanced Fords that brantanly flaunt that fact find an old 428SCJ and check out the little wieght hanging off the crank spacer behind the Damper.I think the old HiPo 289 used the same setup.

    Now about balance holes drilled into internaly balanced or "neutral" dampers they should only have those done to "zero" the damper.Not balance the rotating assembly(Crank, rods,pistons,pins,bearings,rin gs,and the oil too).
    After everything that bolts to the crank throws is wieghed bob wieghts are attached to the rod journels and the crank is spun.To match that wieght either,or both,some holes are drilled in the crankshaft counter wieghts or maybe some tungston,heavy mettel,is added to the counter wieghts.
    Then the damper and flywheel is bolted on and they are hopefully found to not change the balance.If they do then they are rezeroed.

    I've had 4 externally balanced Fords balanced over the last 25years, 2 428cj's,1 5.0l and 1 351w none of them had any mettel removed or added to the dampers and only my first CJ had some removed from the flywheel.
    All had noticable drill marks on the crank counterweights.
    I had 2 SFI balancers and my engine guy did not like to modify those even though he could have because they had the offset type counter weights.

    Boy this is long winded for me.....

    What was the question?
    Oh yea,
    A damper is a damper, but a Balancer can also be a damper ,but a damper is not a balancer.
    Hows that?

  4. #4
    My 302 V8 has a balancer.
    My 281 2V Cammer V8 has a dampener for the internally balanced crankshaft. Goodyear advertises their Gatorback belts add extra harmonic/vibration dampening when the compound heats up. I'm sure other belts do the same thing.
    Last edited by metroplex; 06-30-2005 at 07:19 PM.

  5. #5
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    Modulars are normally setup neutral balance. Notice the hole bored in the front counter weight to "balance" mine.

    When I first built my forged engine, installed a cheap SFI Damper. Well, the hub was too small at the timing cover seal and it leaked oil. So, went back to the stock damper for a while. A few months ago it started loosing the elastomer. Pulled it off and replaced it with an ATI Damper.


    John
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  6. #6
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    MAC, first let me say thankyou for including my post about this from that other thread. I also want to thank you for not taking my post in the wrong way. But let me clarify......sometimes things can get lost through the written word, and because some of us (myself included) can occasionally get pretty intense about this gearhead talk, we can come across as being condescending. And because of that, I believe I have been perceived by some as being condescending in the past when that really wasn't my intention at all. So I'm very glad to see that you haven't taken me that way which is evident in the way that you chose to quote my post. Again, a sincere thanks.


    I think this is simply one of the things about the english language that's just strange. What I mean is, that for some reason it's so common to call vibration dampeners "Balancers", and it's been that way for so long that even businesses list dampeners as "balancers" too. Maybe there was a time in early American automobile production when all gasoline engines were externally balanced, and had a "balancer" on the crankshaft snout from the factory, and that term has just carried over until this present day. It's like how many cars have idiot lights for the alternator that says "GEN" on it (short for Generator) even though cars haven't had generators for many decades.

    I'm not trying to play a game of semantics with you MAC, but the reason why I say that this has to do with one of the many quirks of the english language, is because we have things like "suit cases" that are for "Garments", and "Garment Bags" that are for "suits". Go figure. This also kind of reminds me of how my Dad when he was alive (who was born in 1921) always explained the act of vacuming the living room rug as "Hoovering" the rug simply because at one time a very long time ago, everyone had Hoover vacume cleaners (before my time). But anyway, sorry for my long post, but I still agree with "Cyclone03" on this one. But if you don't agree, I guess I'll just leave it at that. Thanks for your effort to get to the bottom of this, and again, I'm glad that you're aware that I wasn't talking down to you in any way. After all, we all have things to learn about cars and other things too.

    Sometimes I just sit back and laugh at myself, and others for how much we can get real deep with this gearhead stuff. I don't think that it's neccessarily wrong for us to get so deep about these things, but at the same time it sure can be amusing. However, all of my comments about this topic were sincere. Peace.
    Last edited by BillyGman; 07-01-2005 at 12:01 AM.

  7. #7
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    I don't have much to add to this thread other than pictures that happen to be timely. Just days before the MM goes in for a paint job, I decided to yank the 351M I build last year to replace the heads and cam. Why this is relevent is because I had the whole reciprocating assembly balanced and blueprinted.

    The 351M is externally balanced and the ProStreet balancer I replaced during the factory rebuild is both a balancer and a dampener. I wasn't going to make the same mistake I made with the balancer on my 289. (see other thread!)

    You will notice in the picture of the back of the balancer that the weight bob is bolted in. That is because this balancer can be used just as a dampener if the rotating assembly was internally balanced. You will also note the dark ring between the inner and outer sections. This is the elastomer that makes it act as a dampener.

    Ok, the other picture is of the flexplate where the converter bolts up. Notice the top where there is a big nut welded on and looks like it has been hit with a grinding wheel? That is because when you have a pro balance your engine, it can actually be out of balance on one end and not the other! In this case, the rear needed just a tad more weight in that position to make it perfect.

    Cheers!

    John




  8. #8
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    Thanks TooManyFords,
    Perfect timing indeed.

    I would say you have a Harmonic Balancer there.That big ol offset weight is the tipoff for me.


    JohnE showed us a Harmonic Damper,no offset weight added.

    There easy.

    Now,Normal asperation is better!Superchargers just suck air!
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    Last edited by cyclone03; 07-01-2005 at 09:08 AM.

  9. #9
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    Quote Originally Posted by cyclone03
    I would say you have a Harmonic Balancer there.That big ol offset weight is the tipoff for me.

    JohnE showed us a Harmonic Damper,no offset weight added.
    They are both the same...
    Here is the tip off...


    The weight in the center is the balancer for the crankshaft, when needed.
    If you look closely, you will see more sets of holes.
    These can be tapped to place the weight in different locations for different cranks.
    If the crank did not need a balance weight, you wouldn't mount a weight here.

    Now I want you to look at something a little CLOSER...
    The RING of metal around the dampener that is mounted to the center hub with a ring of GREY RUBBER near the edge of the hub.
    The OUTER RING has a spot DRILLED into it. This is where the DAMPENER is balanced.
    The drilled holes can be placed in any location, in any number and depth,
    to remove metal from the ring to balance the dampening effect of this ring.
    The rubber ring between the two absorbs the shock of the crankshaft twisting
    as the outer ring stores and releases energy into the hub to counteract
    the twisting of the crankshaft.
    The amount of drilling removes the weight necessary to add just the right amount of dampening,
    so that the crankshaft's end result is a smooth rotation.
    Pete...


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  10. #10
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    OK....

    I'm done.....

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