At 9:03 AM +0000 8/23/96, Moody, Mark wrote:
>The little springs below the points the control the weights... When tuning I
>found that ohey did not match. One was light weight like a ink-pen spring
>and the other was VERY-very heavy steel ( for it's pint size). Is the
>proper progressive....or merely mixed up parts? Should they match? thanks
Hi Mark,
They should not match. The two different springs give you a rapid timing
advance at low revs, followed by a more gradual advance at high revs. The
factory manual (or reprint thereof from various places) gives the actual
curves. Note that this counts on a little "slop" in the hookup of the
heavier spring, so that it won't have any effect at the beginning of the
advance curve.
A good ignition shop can toss your distributor on a test jig and map its
advance curve, or you can do it yourself on the car with a strobe light and
an accurate tachometer. In my experience most old TR3 distributors are
pretty far off spec, because of tired springs and wear in the weight
pivots.. TRF, and perhaps other places, are selling newly manufactured
springs which they claim are accurately matched to the original specs.
-john w.
jtw@lcs.mit.edu
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