John :
IMO the point gap itself is not particularly critical (and is somewhat
difficult to set precisely), hence the specified range. Of course, the
point gap also affects timing, which is more critical (and is why you
should set the point gap before setting the timing, rather than after).
Either too wide or too narrow typically causes performance problems
(starting with loss of power) at high rpm. Too narrow can also cause
problems with rough idle, hard to start, etc., especially if the bearings
are worn. Until the gap is really badly off, though, the problems are
pretty subtle. Except for a possible change in gas mileage, I doubt you
could tell the difference between .013", .015", or .017" on an otherwise
healthy engine.
YMMV
Randall
On Tuesday, July 11, 2000 9:06 AM, John A. Simmons
[SMTP:jsimmons@intrepid.net] wrote:
>
> 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.
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