harmonic balancer questions

How goes the struggle? :>)

The harmonic dampener "absorbs" the (harmonic) torsional vibration of that crankshaft, which normally will start happening at about 1000 to 1500 rpm crankshaft speed; this happens on all engines.

At this speed, the crank is actually trying to 'warp' along its lengthwise axis and is trying to make the ends of the crank rotate in a larger "arc" instead of staying true in a straight line.

A bad dampener can show up in one of two ways and usually involves the rubber tearing loose from either the hub or the weight: Sometimes it will tear loose & ‘slip’ around the rotational axis and the timing marks are not where they should be. Or, at other times, the engine will vibrate when it reaches this 1000 to 1500 rpm range. It is kinda like a rattlesnake, once you are accustomed to it, you never forget it.

Did you hurt the dampener by putting it on cold? Nope, not as long as you were working on the "hub" portion of the unit and not the outer weight. Beating or pressing on the outer weight could cause it to tear all over again.

Hope this helps,

Allan

Big help. Thanks. One more question though. If I understand you correctly, the weight and hub are connected by the rubber, right? Or are they one piece? So if I ever wonder about the harmonic balancer on an engine, I just need to see if I notice a vibration around half idle. It is something I have never had to replace, and consequently never knew much about. Thanks again

Yes, they are comprised of two pieces, which are held together by the center vulcanized rubber section.

If you have ever felt a pickup or car with a torque converter that was bolted in wrong, that is how they feel; only this shudder is happening at off-idle speeds.

You can think of 'em as a "motor mount designed for the crank". They essentially do the same function. Absorb and offset the vibrations.

I’ve only run across two or three bad ones in my lifetime, but when they are bad, you sure know it.

Allan

If your's has never been replaced, you may be due for a new one, as the rubber insert hardens over the years of heat and vibration, and no longer may be absorbing as much torsional vibration as it should.

While they aren't cheap, replacement is a heckuva lot cheaper than a broken crankshaft, and probably ruining the block along with it.