<VV> RE: Engine miss with rapid tach movement

[Eric S. Eberhard]

Tachs do not measure engine speed.  They measure electrical impulses.  For 
example, if the car is turned off the tach is reading zero ... even if it 
is rolling down a hill in gear (and hence there is an engine speed).  Tach 
bounce is always either a tach problem or an electrical problem so you seem 
to be on the right track.  If it were my car (I do this to all of mine) I 
would:
         1) Put Petronix II Ignitor ignition and coil on
         2) Put 8mm wires on
         3) Make sure plugs are good (I am using Silverstone 6s or NOS AC 
plugs right now)
         4) Make sure you bypass the resistance to the coil :-)

Then it will run very well.  If you want to go crazy install an MSD 
6a.  Note -- this does not mean you can completely ignore a bad distributor 
... the Ignitor II will allow you to run with a slightly bad Distributor 
and will compensate for it just fine.  But there is a limit.

At 05:00 AM 5/12/04, VairMech@aol.com wrote:
>In a message dated 5/12/2004 12:24:53 AM Eastern Standard Time,
>dsjkling@sbcglobal.net writes:
>The miss is intermittant and it occurs at random.  Sometimes
>it is barely noticable and all but goes away.  It is accompanied by the tach
>needle moving, sometimes as much as 400-600 rpm but the engine itself isn't
>changing speed that rapidly.  It doesn't seem like this would be on the
>output side of the coil but since I already tried the cap and rotor, I may
>try plugs and plug wires.  If that doesn't fix it, then maybe the
>distributer itself is not as good as I think it is.
> >>>>>>>>>>>>>>
>     That sure sounds like point bounce. Try closing the gap on the points 
> and
>also check the play in the pivot point of the points plate. A very worn
>points plate will cause something like this as will a weak spring on a set of
>points or the points set at to big of a gap.
>     Ken Hand
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Eric S. Eberhard
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