Message text written by "John A. Simmons"
>I was giving my '71 TR6 a tune-up and while setting the contact point gap
it
struck me that both my Bentley and Haynes manuals state a range of .014 to
.016 for the gap and for some reason I thought, "how odd, its a range and
not an exact number". So here is the question, and I'll increase the range
to .013 to .017 just for grins; What difference does it make to the running
of the car setting the point gap to .013 as compared to .017? What
difference would it make with a new distributor as opposed to one with some
cam wear? Not looking to become a mechanic, just curious.
John, '71 TR6
<
John,
Changing the point gap also changes the timing since the points now open at
a different point on the cam. If you are going to run this test be sure to
reset the timing after each gap adjustment or you will be running a test on
timing changes more than anything else.
Point gap also sets the dwell (time that the points are closed and current
is ramping up in the coil. Shorter dwell times means less current in the
primary upon point opening and hence less bang for the spark.
How this effects performance varies with the state of the rest of the
ignition and the carburettor setting and a host of other things.
Dave
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