Viscous Coupling Tests

I am in the middle of testing a stack of 5 viscous couplings.

The test involves turning the VCs at various torques (such as 25 foot lbs.
and 50 foot lbs.) and seeing how many revolutions they go around at the
prescribed torques.

Based on tests with the VCs inside the diffs the preliminary results seem
to be that.

1. at 25 foot lbs. the torque wrench typically goes around about 1.7 times
within the time space of 1 minute

2. at 50 foot lbs. the torque wrench typically goes around about 3.5 times
within the time space of 1 minute

These tests are preliminary as they were done with the VCs inside the
diffs. I plan to retest out.

With one particular VC I noticed that these results were about double the
revolutions per minute.

I will post a new set of results showing how all the VCs do as I prepare a
more exact test. I have found that it is a very simple matter to pull the
VC out by undoing the zillion little bolts going around the diff and then
pulling the end of the diff off.

In addition, I plan to heat the VCs and retest them. This ought to show
those VCs which are bad only after a period of highway driving. Tim Smith
suggested something like 212 degrees for a retest (cannot remember C or F)
so I have to guess at the operating temperature of a going-bad VC after it
has been on the highway for 1/2 hour.

Any list members that want a graph of their VC's performance by temperature
and by torque are invited to send theirs to me for analysis and testing
compared to all the other VCs that I have. I will test it and send it back.

The cool thing is that I have a VC that is half baked--it seems to be OK
but it does the highway heating thing. So by finding out how this thing
differs from its peers, we can nail down a way to find bad ones.
_______________________________________________
Derek Drew                  New York, NY & Washington DC
CEO, ConsumerSearch
drew@interport.net
212-580-6486, 202-966-7907 (Work)
212-580-4459; 202-966-0938 (Home)
     (cell: 917-848-6425)