[Roadsters] Spark Plugs - General Info, Key Phrase

[Daryl Smith]

> So if Roadsters often tend to run rich (at idle or otherwise due to 
> mistuned carbs, needle profiles, etc) then the hotter plugs would be 
> helpful to burn more of the fuel, keep the plugs from fouling and in the 
> process, possibly a bit more power as a result? Sounds good to me.
>
> Linda

If it is an otherwise good engine you are probably better running the 
correct heat range plug with an upgraded ignition system. With the SU's you 
may be rich at idle, and lean at higher rpm, and a hotter plug in an already 
lean condition could cause detonation.

The only reason I've heard for using a hotter plug on a stock engine was 
when it was worn and starting to burn oil. The hotter plug would burn off 
the oil better and not foul as easily.

Daryl

 >
>
>
>
>
>
>
> -----Original Message-----
> From: O'Farrell, Fergus <Fergus.OFarrell at ngc.com>
> To: datsun-roadsters at autox.team.net
> Sent: Wed, 18 Jun 2008 7:09 am
> Subject: Re: [Roadsters] Spark Plugs - General Info, Key Phrase
>
>
>
>
>
>
>
>
>
>
> <<  No performance improvement with other plugs?  >>
>
> Yeah Linda, that write-up was very informative, but I found the key
> phrase in all that to be:
>
> <<  One thing to keep in mind with respect to performance claims is that
> no spark plug creates horsepower out of thin air. A special electrode
> configuration can reduce misfiring and the voltage needed to fire the
> plugs. But the spark only ignites what is already in the combustion
> chamber. If there are any power gains to be had, they will be the result
> of reduced misfires and nothing else.  >>
> We get the most gains from GB's EI dizzy and the hotter spark (larger
> gap) that can be run, and the fact that the hotter spark keeps plugs
> from getting fouled.  Gains come from changing the flame front within
> the cylinder, flows in/out of the chambers, fuel atomization, etc.  (etc
> meaning: and a whole long list of things that I know diddly about)
> A friend of mine designed a plug holder to put modern Ford F-150 plugs
> (tiny, but HOT spark) into hi-perf Harley motors, which included a
> compression release so that the stock battery (small) could start the
> larger displacement motors.
> He had large HP gains, but admitted it was probably because the bike was
> running so rich prior to the swap, that all he was doing was burning all
> the fuel that had always been there.
>
> Fergus O, 69 2000, HB, CA