Hi, Jack.
At 07:56 PM 10/11/00 -0700, you wrote:
>This is the first time I heard about this for trucks
>without MSD etc.
>How/Why does the .045 get better mileage or
>How/Why does the .035 get better performace?
>I just want to understand the engineering.
This is my understanding.
As the ignition is triggered (and sends the spark through the rotor,
to the cap, down the wire and then it jumps the gap of the spark plug),
a spark kernel is created that ignites the air/fuel mixture in the
combustion chamber. How well this is done is a combination of proper
timing of this spark, proper heat range of the plug as well as the correct
gap.
On stock or aged ignitions, opening up the gap 'CAN' increase the spark kernel
size, thereby creating a more efficient burn which, in turn, 'CAN' mean better
mileage. The problem lies in that any added gap creates more strain on the
other
ignition parts.
On stock ignitions, cylinder pressures at high rpms require more energy
to jump the spark plug gap. Smaller spark plug gaps 'CAN' help to accomplish
this. The problem, in this case, lies in that too small a gap 'CAN' create
misfire or fouling.
Hope this helps.
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:55:59 EDT