Originally Posted by 98tacoma27
Better conductivity. Plus, whats the point in using aluminum to pretect steel from aluminum.
I know they are both "filled" with various oils and greases, but I prefer to use the copper over the aluminum in this application.
Huh, that's interesting. The copper spec specifically mentions the application to plugs in aluminum heads, whereas the aluminum spec sheet does not have this additional detail (just says spark plugs).
Also, the spec sheet for copper says it is for up to 1800F, and the aluminum type is rated 200 degrees lower (1600F). Not that I have a clue what the typical max temperature range is in my V6 heads.
BUT, note that for the low-end temp, the aluminum is rated down to -51F, but the copper only to -30F, so maybe our friends in Minnesota and Canada should take note for when they are changing their plugs outside in a blizzard.
All that said, I have always used the aluminum and never had a problem...but maybe when I run out, I will swich to the copper, just to be, uh, like, all anal like Ben. (Seriously, I appreciate your attention to detail!)