Marelli engine, idle stumble

[sbobev (Steve)]

@Paul_M_Novak

I wonder if

your BR7EF plugs or the 0.035 inch gap you set are contributing to the

stumble problem?

Paul:

[v12-engine] 6.0L V12 - the FINAL word on spark plug gaps

Gentlemen: I’m due for spark plugs replacement and need to confirm the correct gaps for the 6.0L V12. Search through the archives suggests that the last of the V12 engines required 0.035’’ gaps, not 0.025’’ as their 5.3L counterparts. However, my JDHT manual specifies NGK BR7EF plug with 0.025’’ gap. Several old threads also talk about 0.025’’ gap and the possibility that it is plug-dependent, for example: http://forums.jag-lovers.org/av.php?780381q14 What is the FINAL word on the cor…

To recap the discussion, BR7EF and BR7EFS are the same plug, sans a small difference in the shape of the electrode.
And apparently, 0.025" is the sweet spot for the gap for all v12.

Steve