Re: Crankshaft Balance and the Rubber Donuts

[Otto Schug <schugof@domain.elided>]

Alfisti:

Thank God!  At least one of my concerns about the balancing of the driveshaft has been answered by omission.  I always thought the front flywheel was balanced (I see holes partially drilled therein at different locations); the clutch flywheel was balanced (I see holes partially drilled therein at different locations); the front driveshaft was balanced (I see different plates welded thereon at different locations); the rear driveshaft was balanced (I see different plates welded thereon at different locations; the splined connector connecting the front and rear driveshaft can only be connected one way and, therefore, must be balanced; and, the splined connector at the clutch flywheel can only be connected one way and, therefore, must be balanced.  Thus, by omission, one must agree that all three rubber donuts must be made so true and correct that they are always balanced.  Really?

All you have to do is make sure the front spline (which can only go on only one way and, therefore, must be balanced) settles in to adjust the forward-rear location of the driveshaft between the front flywheel and the rear clutch flywheel.  Therefore, you have the system balanced from front to rear and sideways to sideways.  Of course, one should not worry about the third dimension of up and down and, therefore, should not raise or lower the driveshaft at the center support by the use of shims to ensure that the driveshaft is level.  Really?

Logic then follows that if you destroy any of these entities, you must junk the car because all this balancing work was for a particular car, not of the independent peices.  Who, in his right mind, would think to make the independent peices balanced so they could be interchangeable with new or used parts of the same type.

Now, consider the problem of trying to calculate where is the out-of-balance on a driveshaft when you take one in and out, change donuts, change balanced clutch systems, change bearings, change center supports or change any other part on the system.  The car itself would have to be measured so that it is perfectly level with earth (gravity) or the driveshaft will be tilted.  If you don't keep track of the shims (spacers) or any spring washers, junk the car.

Don't worry, I have had donuts go bad and destroy spline connectors and driveshaft ends.  Yes, I can hear, because I am petrified with any sound, whinning of the driveshaft after replacement of same.

In an absolutely perfect world, you would never have to worry about the driveshaft.  But, the donuts still go bad through normal use.  Alfa, of course, never anticipated that the donuts would wear and race drivers know, even though they disconnect the driveshaft many times during a racing season, that the system must work.

Therefore, I have read the gloom and doom of the driveshaft balancing problem.  However, I have not read in the Digest about any method to correct a driveshaft balancing problem or how to install a new driveshaft system and get the system balanced.  The best I have read is to use, with trial and error, a hose clamp at different (120 degrees) location around either the front or rear driveshafts in order to increase, alter, locate or correct an out-of-balance problem.  Surely, the Alfa race drivers have an answer, because their problem, at high speeds, is real and is now.

Alfa engineers, mechanical engineers and Alfa race drivers should give their input to solving the problem, because no reasonable person will keep all of the parts of the driveshaft system perfectly marked each and every time the driveshaft is changed.  In fact, I did mark all items and the driveshaft system still chewed up a donut in reasonbly quick dispatch.

Now, lets read from someone how to balance a system that is out-of-balance.

Otto F. Schug    schugof@domain.elided

10 Alfas with son
Yahoo! Health - Feel better, live better
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided