Do I need a Harmonic Balancer Crank Damper? – Jay’s Tech Tips #31 – Real Street Performance

Do I need a Harmonic Balancer Crank Damper? – Jay’s Tech Tips #31 – Real Street Performance

Hi, I’m Jay from Real Street Performance. Today, we’re going to talk about harmonic balancers, and why an aftermarket one is better suited than your stock one. The harmonic balancer is a weighted pulley that mounts on the nose of the crankshaft to absorb the inherent vibration that happens when you’re running your engine. Your factory harmonic balancer consists of 3 pieces: the hub that slides on to the nose of the crankshaft, a piece of rubber that wedges between the hub and the outer ring to absorb vibration, and the outer ring that typically drives the drive belt. As the factory balancer ages over time, the rubber deteriorates. And it will allow the ring of the balancer to slide off of the hub. The factory balancer could also fail by changing the frequency that the engine operates in. So if you change the reciprocating parts in the engine: pistons, rods, things like that, it changes how the engine was balanced and what vibration it makes. High RPM can exceed what the factory balancer was rated for, creating the condition where it can swing the ring off also. Your engine needs a harmonic balancer because there’s inherent vibration in the reciprocating parts. So what happens when the engine doesn’t have a balancer on it, if you have an engine that is a single speed like a generator that just ones that runs at one speed or a lawnmower that runs at one speed, there isn’t a wide range of RPM to tune the harmonics out of. But with an automobile engines and drop ratings from a 1,000 RPM to 10,000 RPM. You need something to pull that vibration out as the engine frequency changes. It’s important to tune out these vibrations because it can hurt the oil pump, if you have a crank snout driven oil pump. It can drive the valve train into harmonics if you’re using a timing chain engine where the vibration is transmitted from one side of the engine to the other. It can rattle the flywheel loose. It can split the hub. You can see vibration on the face of your bearings and your main bearings if the engine is vibrating a lot. You can also see it in the main caps if there starts to be some micro welding. On the nose of the crankshaft, you can see some prints where the balancer is actually shaking on the nose of the crank during severe duty. Because again, we’re not treating these engines nice. We’re making 2, 3 times their designed power output and with that comes additional stress that needs to be dampened. A quick example of an OE manufacturer combating this problem is the 2000 Ford Cobra R. Ford had been building the modular Ford for years. And when they decided to put together the Cobra R, which would be a road race style vehicle, they had to add weight to the crank balancer [to the harmonic balancer] to help absorb the vibration that was being driven back into the oil pump and to the other reciprocating parts. Because the factory balancer deteriorates over time, you should consider buying an aftermarket balancer. The aftermarket balancer doesn’t necessarily add a lot of flash. It doesn’t necessarily add a lot of horsepower, although it can add horsepower by reducing the vibration in the engine. It’s basically about longevity. When the stock balancer fails, things break. If you’re racing your car in a sanctioning body, they normally won’t let you race under a certain time or class with a stock balancer because they know they fly apart. And that ring can become a projectile in addition to its problems that it gives your engine. The aftermarket dampers are constructed differently. One of them is for safety to have good containment so the isolator is mounted inside the balancer where it cannot exit the balancer. They also have a tighter tolerance on the hub of the crankshaft. So the fit from the hub to the crankshaft is going to be a bit tighter. And that’s going to allow more vibration to be transmitted directly into the balancer instead of lost through a loose fitting balancer. As an example, I have an ATI ring here. This is the dampener. They use different durometer o-rings that will isolate the hub of the crankshaft to the ring of the balancer. And they are tunable in some degree for different engines, but they generally have a good safe setup for engines that are over the factory power level and will meet a class or NHRA rules. A quick installation tip if you’re installing one of these balancers is you’re going to want the engine cold. And you’re just going to boil this hub in water. So get this hub over 200 degrees. Put some oil on the snout of the crankshaft, and you’ll be able to slide it on that way. If you try to put this on cold or put this on cold with the hot crankshaft, that’s not going to fit. There’s too much interference between the 2. So this has to be hot, engine has to be cold. This will get on the nose of the crankshaft. The harmonic balancer is not a flashy fun part. It’s not something you’re going to brag about to your friends that you’ve just purchased. However, it is a key component in your build. And you should definitely budget for it. The price of the balancer versus the risk of not having one, it’s a no-brainer. So just put it on the list of things that you need to purchase for your build to make sure that your engine can live a long and healthy happy life. Thanks. See you next week.

About the Author: Michael Flood


  1. I have an under drive pulley kit on my K series.. Does the ATI pulley replace that or run off a separate pulley.. Thanks

  2. My builder literally made me buy one and ditch the 'lightweight' crank pulley on my Subie. Heck, it could have been a culprit for all I know. Thanks Jay for another good video to show people real life scenarios and actual facts. This is certainly one part that gets overlooked on many modded cars. keep up the good work on the videos guys!

  3. Thanks Jay! As usual only the best informative info on part's we see everyday but not really understanding the importance of them until explained in detail! Realstreet's the Real deal.

  4. why do dodge srt4 engine builds always end up deleting the harmonic balancer? anyone have some insight on that?

  5. If you get these random vibrations during idle, could it be harmonic balancer? Changed to solid mounts 3 yrs ago and have this vibration during idle. Almost seems like care is about to stall out sometimes.

  6. I can't find a balancer for my mazdaspeed 6 the balancer is toothed for the crank position sensor maybe that's why they are rare

  7. How about underdrive pullys and the rumors that engine accessories will suffer? Can they still dampen out engine vibrations as well as factory? thanks

  8. People are getting dampers confused with engine balancing, and probably because people keep calling them the wrong thing. They are not called harmonic balancers. You don't balance harmonics, but you can dampen them. Thus, they are called HARMONIC DAMPERS.

  9. I'm planning on having the ATI super damper installed on my 07 Z06 with an 10% under drive. The OEM just doesn't last very long. I'd rather pay 3 or 4 times the price over OEM than to have to deal with it again sooner.

  10. i have vibrations in the car from 1200 to 2000 rpm
    engine feels smooth in the time the car vibrate
    rb26dett r33gtr
    any idea

  11. So I read some replies and still don't know. Not sure of the difference on balancers and dampeners. Still go in the same spot right? Front of the engine? My engine (350 Chevy) vibrates a lot at higher rpms. I was told it could be the flywheel or clutch plate…then yesterday a transmission guy says it's rare and he's never seen that before. Says its gotta be the balancer…..???

  12. I'm doing a diesel engine swap. It's an older Cummins A series inline six. Made before the famous B and BT series. This engine is the outside size of a 300 CI Ford inline six or a GM , JEEP inline six. I'm having to fabricate everything about this swap including Flywheel and Bell housing. I gotta get with Cummins and see if they can recommend a balancer for the front because it only now has a direct drive V pulley. I have a couple inches between the flywheel and the back of the block. Would it be a good idea to mount a harmonic balancer on the flywheel itself to help the whole engine be smooth? This engine has a cast iron crankshaft which I thought was odd. I sure don't wanna break the crankshaft as I've seen done before when using cast iron crankshafts. I'm wishing to use Teflon around the flywheel bolts to take out part of the jarring when the clutch is engaged. Would this be possible to take the shock out of engagement of the clutch?

  13. Can a bad SFI harmonic balancer that's gone bad ….keep eatting the front seal out of my 302/347?? I keep having to replace them …and when pulled out they look like a dog chewed them up …also it's a Supercharged build ??? please help ….

  14. Please don't tell me I need this on my 156K 1999 Ls1 Camaro I get a bad vibration at a low RPM if when in Park, Neutral, or driving at a low RPM like under 2KRPM. Been doing it since 140K miles. Will I ruin the bottom end of the engine or driveshaft? I try to run it at a higher RPM and it goes away.

  15. can you run a lightend crank pulley with no damper on an automatic car considering it has that huge torque converter filled with fluid on the other side?

  16. This is an old video so hopefully you can answer my question, but is a fluid damper needed if you're running a stock engine with an aftermarket light weight flywheel since it's a recipricating part of the engine? Reason is I recently installed an ACT light weight flywheel on my s2000 ap1.

  17. I have a Honda crx which came from the factory with no dampening at all just a steel pulley I "upgraded" to an aluminum one and had the machine shop balance it. After watching this it makes me want to put on a heavier stock dampener. Since the alum one weights less than a pound

  18. Quick question! On my B18C I want to run the alternator only * no power steering or a/c , but I want it to still charge my alternator for accessories like headlights. I have heard the *RACE Damper will not charge well on a bseries. Is there any way to use the Race version on the street or buy a super damper without the extra a/c and p/s pulleys?

  19. Without the vibration damper, the engine experiences torsional vibration – the front of the crankshaft moves back and forth with respect to the flywheel. This can cause a very rough running engine at certain speeds and the back and forth rotational motion of the crank will eventually overload the rod bearings toward the front of the engine ultimately leading to failure.

  20. Hi, I just installed an ATI Super Damper with 2% overdrive and lightweight hardware on my MINI R53 and I’m hearing like a wiring sound, almost like if there’s a strong airflow going through the pulley, is this normal or could have possibly installed it incorrectly like maybe too close the the wall and it’s scraping? Thanks!

  21. Hi Jay 🙋🏽‍♂️
    Just i would like to know your experienced idea about 2jz wobbly timing belt between intake cam shaft pulley and crank pulley while engine revving around 3,000 rpm…
    Thanks for experienced ideas 💡

  22. You are being scared by someone who is being paid by a damper. company to influence and lie about how solid pulleys are bad for import engines.

  23. Question for you if you don't mind.. I have an Audi a4 Quattro 2.0t. It's engine is stock, but even after replacing the engine mounts and the transmission mounts, I'm still getting some vibration when I put the car in gear. I'm not moving, jus in gear with my break on. Do you think that could be my hermonic balancer? The car drives great and ONLY vibrates when I have my foot on the break and put it in gear..

  24. I'm running perrin lightweight crank because it really does free up hp and i dont mind rebuilding after 150k to have reliability but thats my opinion

  25. I made the mistake of buying and eBay lightened underdrive pulley/dampener for my DSM it completely change the low RPM and start off characteristics of my engine it was like having a lightened flywheel I had to go ATI to get my daily drivability back.

  26. Great vids that I always keep coming back to.
    I wish Evan or Jay was on the west coast for sure. These are two tuners that I would love to have at my disposal to tune with.

  27. How about having the rotating assembly of the engine balanced? I am a fan of that for helping to reduce engine vibration.

  28. Should there be any slack between the crankshaft gear washer and the timing belt? Reason I ask is the ring/washer rides against the belt and was unsure if the ring/washer is suppose to spin freely between the gear and belt after the damper is torqued down. Thanks.

  29. I’m buying a Procharger for my 6th Gen Camaro SS, should I put a new balancer on it (I’m only looking to make 600hp @ rwhp) or will the stock be ok?

  30. can I mount 24 1-karat diamonds to the face of my balancer to give it some bling? as long as they are all the same weight and equally spaced apart, I don't see an issue?

  31. Can anyone please let me know if a harmonic damper will make a whining noise when it’s bad
    I have a 1999 vw golf 2.0 and there’s a whine that seems to come from it

  32. hey guys ,so a bad harmonic damber can affect the power and rpm of my car ? i have a sportage 1996 gasoline with harmonic damper just cracked :(….

  33. I'm in the middle of my 2jz build and I was using a cheap "flashy" aluminum pully set. I had no idea how important having an actual damper/balancer is. Thank you!

  34. i had my chevy 383 stroker internally balanced. i am running the 400 balancer on it now. but im about to change it to a 6'' street balancer. is it going to throw off my internal balance ? and cant i just change out the short timing marker for the longer one to keep the correct timing setting ?

  35. Honda F and H series from Accord and Prelude where 2.2l-2.3l had extra balance shafts in the block that ran along with the crank driven by a timing gear.

  36. Thx for your tech tips. Theyre very useful and contains topics which normaly nobody thinks about. After watching this video, a few months earlier, i purchased an ATI for my rb26.

  37. I change to Work Engineer lightweight pulley on my K car, which they claim to have pro balance technology. I am not sure how safe is it, still monitoring after a year plus.

  38. I'm thinking the ATI pulley might be a bit too tight for mine.

    1.3820 inches crank snout OD vs 1.3745 ID ATI hub.

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