<VV> Spark plug gaps

[FrankCB at aol.com]

Tony,
    I certainly agree with what you recommend assuming  it's for a STOCK 
ignition system.  However, I SUSPECT (but I'm not sure)  that a GREATER gap would 
be better for engine operation IF the system were  changed to an electronic 
ignition that can supply much higher voltage to the  plugs.  I seem to remember 
that modern electronic systems in modern cars  use a significantly GREATER gap 
(like 0.060 inch).  When I  changed the plugs in my 1966 Monza (with 
electronic ignition) many years ago  after high mileage the gap had increased so much 
that none of my gap  measuring tools could measure it.  The center electrodes 
were worn  (eroded?) down to level with the ceramic insulation surrounding 
them.  And  the engine was STILL firing just fine - I was doing it for 
"preventive  maintenance"
    But does anybody have any EVIDENCE either agreeing  or DISagreeing with 
my suspicion that our engines would work better with a  greater gap?
    Frank "questioningly" Burkhard  
 
In a message dated 9/19/2007 12:27:44 PM Eastern Daylight Time,  
tonyu at roava.net writes:

This is  how the engineers at GM found the engine to do its best work, 
via tests  etc. thus their findings that .03 seems to work best  
over-all.


>However, NGK, AC and Autolite all recommend  .035


Recommend.   They don't actually know what the plugs  are going into.


>for their plugs, but Bosch says .030.  So  what do folk normally use, 
>and what do you think works best?  The  motor is a 110 with stock 
>points/condensor/coil  ignition.


You won't go wrong with the factory recommendations on  plug gap 
etc.   After all, it's their engine design and their  findings from 
their R&D people.   The plugs are pretty much  a standard in that they 
all do the same thing and the gap setting is in  response to the 
conditions inside the combustion chamber, ignition source,  mixture, 
timing, etc.

tony..  







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