[Fot] TR4 Spark Plugs

[Tony Drews]

I use NGK BP7HS.  My recollection is that the BP8HS is hotter and the 
BP6HS is colder.

Tony

At 10:45 AM 10/22/2012, Scott Janzen wrote:
>I am prepping the recently acquired TR4 for the Turkey Bowl at 
>Summit Point (Thanksgiving weekend) and thought I would get some new 
>plugs.  The current plugs are NGK BP8HS-10.  These come up in google 
>searches as being used for marine applications, though there's 
>nothing in the part number that indicates that use.
>Engine is about 170 psi compression, 12:1, guessing from the cam 
>that the engine will be running between 4,000 and 7,000 RPM.  Plugs 
>are running light-medium brown, so apparently about the right heat range.
>Recommendations for plugs, or should I stick with what I've got?
>
>Here's the current spec:
>non-resistor plug
>Thread Size: 14mm
>Thread Reach: 12.7mm (1/2")
>Hex Size: 13/16"
>Heat Range: 8
>Gap: 1.02mm (.040")