Posted by Dave Horvath [162.158.79.248] on Sunday, April 23, 2017 at 18:32:55 :
In Reply to: Externally Balanced Crank posted by Dave Horvath [162.158.79.248] on Saturday, April 22, 2017 at 17:53:46 :
Interesting that the responses were split about 50/50. Turns out it is a vibration damper/harmonic balancer. Came on high-end models of car engines. The rubber can delaminate, allowing the damper to spin freely. Apparently, it can be removed with no ill effects. Several guys on other forums removed theirs and reported no problems. Here is the best description I found:
"All of the Mopar engines were balanced both statically as well as dynamically. All piston and rod assemblies were held to very close weight tolerances, the crank was balanced as was the flywheel and clutch assembly.
The harmonic balancer if installed acted as a harmonic balance so as to absorb harmonics.
All engines with an equal number of cylinders in length, 2 4,6 and 8 suffer from the 3rd, 5th and 7th harmonic vibrations and the balancer was installed in an attempt to negate these harmonics. Engines with an odd number of cylinders in length, namely a 5 cylinder, a V6 (3 cylinders long) and a V10 (5 cylinders long) apparently don't suffer from the harmonic issues.
In the case of the Plymouth without a harmonic balancer it is most probably the fan belt that is driving the radiator fan that acts as the balancer."
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