Gid'ay Darrell,
Can't answer the spare parts questions.
The Harmonic ballancer, does what its name suggests, it dampens the Harmonic vibrations that happen in the length of the crankshaft. This is a winding up and unwinding of the crank as cylinders fire to power the driveline.
When no.1 cylinder fires, it winds the shaft up to turn the flywheel, when the power pulse has reduced, the flywheel will unwind the shaft to drive the cylinder over its idle strokes. As the engine revs rise, there is a time when the wind-up from the cylinder meets the un-wind from the previous firing. When these oppersit forces meet, they stress the crank, and it can crack, at this spot.
The length and torsional flexabilty of the crank, controls the rpm that these harmonic virbrations occure. If they occure at a rpm that the engine normally sustains, the engineers tune the ballancer by adding a weight, mounted on rubber, to move it to some other rpm, that is usually past through quickly, so that the crank is not subjected to the stress for too long.
Remembering that this car was designed to tour at high speeds, it would sustain the range from 4000 to 5000 rpm for a long time. So this is where they would ensure the harmonics did not occure. Where did they move them to?????????
I doubt that the damper from a 4 cylinder would be the same, as the length of the crank is much shorter. The harmonics would be much less, and designed to occure at a different rpm, as they don't have to sustain the high rpms.
I think there was a design fault in having the rubber isolated weight, also driving the accessory belts. The type of belt needs more tension than the rubber can stand, so it gets worked harder, to fail earlier.
As to the long term effects of replaceing it with an alloy one. If the car is driven at sustain high speeds, sh1t will happen.
. If it is driven like most drivers seem to, at low engine speeds. It may not. For my money, I'll keep replacing it with the standard ballancer, and not over tightening the belts.
Harvey.
