polar gap plugs [Alfa info]

[Carter Hendricks]

On Tue, 16 Apr 1996, orlin steven jared wrote:

> > >engines at Autolite they can't even be made to pre-ignite.   They
> > >would also foul out pretty quickly after a few cold starts in
> > >a street motor.
> > 
> > Not necessarily . . . they were original equipment in Alfa Romeo 4 cylinders
> > when the cars were still imported.  Maybe the Autolite plugs were colder than
> > the Lodge used in the Alfa.
> 
> Possibly, but I'd be interested to know exactly what plugs were OEM for
> those engines, to see exactly how cold they are.  I don't think they
> used a standard surface gap, but I could be wrong.  Also, the alfa's may
> have leaner starts not so hard on the plug..
> 
> Steve

If the question "those engines" means the Alfa engines, the Lodge spark 
plugs have been oem for Alfa for some time... As I understand it, there
is a long and boring historical link between Lodge and others in England 
and Alfa Romeo. The plugs are now built by [or for] Spica, an Alfa 
subsidiary [though all of it has been digested by the Fiat].

The plugs. They aren't like the Champion Indy car plugs with a retracted
electrode. The center of the plug is pretty conventional with four flat
prongs alongside and almost touching the porcelain. 

The standard plug is the HL, which is/was abt the same heat range as a N9Y
Champion. There is a colder 2HL, which is advised for sustained high 
speed but which is still no race plug think N7Y. 

In my shop, where we work just on Alfas [and some older Lancias, a few 12 
cyl things], the Lodge plugs have been our plug of choice. Its original; but
it also helps stabilize Alfa idle emissions compared to other plugs. The 
older mechanical injection Alfas go through a linear warmup cycle and the
idle stability when warmed up is weak [though 100's times better than the 
alternative [ca 1969 >] Weber carburators.

						--Carter