MSD 6A and OPTI

Shannen Durphey shannen at grolen.com
Wed Nov 28 04:16:21 GMT 2001


> >
> I've never measured the rotor gap in an optispark 
What a great way help the customer to spend $$!  Not only do you replace a
failing optispark with a good one (which does the fix at about $600 - $800 +
labor) but you then sell an aftermarket ignition which accelerates the wear on
the $100 cap and rotor.

> (what all the MSD's where
> I worked were installed on) but I think that last 750hp(rear wheels) car was
> about .060 plug gap. And yes the ignition boxes helped these cars run
> better, especialy the more radicaly built ones. The stock optispark was
> usualy the first thing we would change when a car did not run right, and
> more often than not it would be the problem.
The stock optispark is junk, but installing any multistrike ignition system on
the LT1 is not the best way to go.  Taking the spark out of the cap and rotor is
preferable and there are kits available which allow one to do this.  I have
replaced enough Opti-spark units so I have a pile of old units around which I
can hand out like mints at Christmastime.  I can think of only one case in which
I recommended an aftermarket ignition system which uses the stock "distributor"
portion of the opti, and it was in a discussion which began because the
individual already had an aftermarket ignition installed.  

> 
> On my own cars I usualy just get rid of the factory ignition right away
> (electronics, including module)and install on of my MSD's first thing. I can
> run a much larger plug gap than a stock HEI 

Stock HEI is good for .060" to .080" gap with compression ratios from 8.0 to
almost 10.0 to 1.  The large cap setups were used with .080" gaps from the
factory.  The reason GM backed off the gap is due to decreased spark plug life. 
Using a box with multi strike capabilities and these plug gaps only speeds the
demise of the plug.

> and and can also get away with a
> leaner mixture for cruising.
There is no direct correlation here.  Lotsa factors come into play when heading
for lean(er) cruise mixtures.  Generating a spark (even many sparks) does not
ensure the mixture will burn.  Igniting a flame does not ensure that the
combustion event will contribute power to the crank.  And one good combustion
event does not indicate multiple good combustion events will follow.

This is a marketing type statement of which you can see examples on the back of
the packages for everything from Slick 50 to fuel molecule magnets to intake air
"turbolators."

Shannen
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