FW: Combustion chamber & twin plugs

[Mark Pitts]

This seems to related to the position of the origional plug in the first =
place. My current heads are kiddny shaped chambers, with plug right over =
one side. I know that I need to modify my chamber shape, and valves, but =
it must me worth putting another plug over the otherside. (I,ve always =
been a rever, and not a slugger, my engine regularly revs to 8000 on =
down changes, and the standard 'red line' for the Le Man spec one was =
9000) and for this reason, i.e. I like to rev the nuts off it, another =
plug must help burn time (might stop it knocking as well).
Mark
Any coments?

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From:  jac at wave.sheridan.wy.us[SMTP:jac at wave.sheridan.wy.us]



With the more centrally located plug in=20
operation, the RPM drop from switching the=20
aircraft plug off is almost negligeable.  The=20
drop from switching the central plug off is 400=20
- 500 RPM.

I don't think that it is reasonable to expect as=20
anywhere near much power gain from adding a plug=20
to a system designed with one plug, as there is=20
power loss when a plug is removed from a two=20
plug system.  It is important to remember that=20
there is no advance adjustment at all in the=20
aircraft magnetos under discussion.