[Mgs] NGK plug heat ranges

[Paul Hunt]

Are you trying to lower your under hood temps?  Cope with lower under hood 
temps?  Changing the plug temp won't alter either of those, or be affected 
by them.  It simply refers to how hot the plug tip is allowed to get inside 
the cylinder i.e. at combustion temps.  The longer the nose the slower the 
heat conduction into the head casting and the hotter the tip gets, and 
conversely.  If plug fouling is a problem then one would go with a hotter 
plug, whereas if tip burning is the problem one would go with a cooler. 
Nowt to do with under hood temps.  According to 
http://www.akamoto.co.uk/resource-spark-plugs.htm 7 *is* colder than 6, and 
5 hotter.  Unless you have a modified engine plug burning (or fouling) which 
might lead you to think you need a different temperature of plug will almost 
certainly be due to some other problem in ignition or carburetion, not plug 
temperature per se.

PaulH.


----- Original Message ----- 
> I want to go with a cooler plug in my 67BGT. Using the NGK BP6ES now and
> want to experiment with possible lower under hood temps(still, I know).