Spark plug gap on AQ 151 with electronic ignition

Have a question about the spark gap - my "old timer" mechanic made the gap significantly wider than spec (can't remember the reading offhand) with a comment that my Petronix distributor allowed for this and this also made for easier starting. Any hints as to what the gap should be on my Bosch pugs on my AQ 151 with elect ignition and if this is a good idea?

If your "old timer" mechanic believes that the Pertronix kit calls for a greater spark plug gap, he is somewhat misinformed!

The Pertronix kit replaces the old Kettering system (contact points) with electronic triggering ONLY.

An ignition system using the Pertronix kit with a standard ignition coil, still calls for the standard spark plug gap.
An ignition system using the Pertronix kit with a High Energy coil, may call for a greater spark plug gap!

In other words: Spark plug gap is determined by the voltage that the ignition coil offers, not by the type of triggering system.



.

I cannot confirm or deny that this is true, but per the Pertronix website:

What should I gap the spark plugs to?

The Ignitor has no set specification in which the spark plugs should be gaped at. Every engine responds differently to spark plug setting. In most cases increasing the factory recommended gap by .005 improves the engine performance.

am_dew said:

I cannot confirm or deny that this is true, but per the Pertronix website:

What should I gap the spark plugs to?

The Ignitor has no set specification in which the spark plugs should be gaped at. Every engine responds differently to spark plug setting. In most cases increasing the factory recommended gap by .005 improves the engine performance.

Click to expand...

The less the secondary voltage is (standard ignition coil for example), the gap should be adjusted to OEM specs.
The higher the secondary voltage is, the gap can be greater.
However, there is a phenomenon that causes cylinder pressures to affect the voltage's ability to cross the gap. In other words, higher cylinder pressures hinder the spark's ability to cross (jump) the gap!

As said earlier...... if standard ignition coil..... stick with the OEM gap. If using a High Energy coil..... try increasing the gap.

I would not haphazardly open the gap without knowing the cause/effect!

Feel the coil after running for a bit if it is getting hot install a ballast resistor to coil posative. The pertronix module requires battery voltage so if it is using coil posative put hot to the module before the resistor. On those older ignitions you can try different plug gaps for the best performance. You should get the spark to jump a gap of at least 5/8 inch open air gap.

Thanks for all the comment - have purchased a new set of plugs and will experiment a bit. Will see how it goes and report back.

Have fitted new plugs to spec (NGK - have started a new thread) and also looked at the fuel (started another thread on this too!). Sticking with standard - specs- gap at the moment as standard coil (Buru that goes with my Pertonix). Cleaned up the fuel filter too so there are a few variables here but engine now firing much better at start. All the comments add up I hope to what should be a fairly reliable AQ 151. Thanks for the input.