[Diy_efi] Spark Plug Projection into Combustion Chamber

[Neil.Poersch at mts.ca]

This question is only peripherally related to EFI but I know that there is
a lot of engine building expertise on this list so I hope you don't mind.

I am machining my motorcycle cylinder heads to add a second spark plug to
the combustion chamber.   I am wondering if anyone has any recommendation
as to how far the plug should project into the combustion chamber.    I
have seen some installations which recess the plug in a shallow pocket
(~0.1" deep....really not much more than a chamfered edge of the spark plug
hole) in the roof of the combustion chamber.  This is supposedly to allow
the ignition spark to start the flame in a protected area.

Any comments from anyone?

Obligatory DIY_EFI content:   I will be using my DIY_EFI WB O2 meter to
fine tune my AFR once I have completed the dual plugging project.
Theoretically the engine should run on a leaner mixture than before.  This
should be a good example of not tuning to a particular AFR but instead to
the AFR that produces the best power.

Neil



_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi