In an effort to improve my recent poor idle (as posted elsewhere) I
bought a set of NGK spark plugs which have a V groove in the centre
electrode.

It's tempting to think that these are intended to give two sparks
instead of just one, but actually I think they just help to define the
'launch' point of the spark. In circumstances where spark formation is
relatively difficult I thought this may be an advantage.

I was wrong.

In fact they made the idle worse - lumpier and more erratic, and I
couldn't tune this out by other means (ignition timing or mixture).
Above idle speed I couldn't tell the difference, but they didn't get
more than 100 miles to demonstrate their worth.

They may do marvelous thing for an engine running on petrol, but in
harder-to-ignite LPG they only made things worse.




--

Stewart Hargrave

A lot faster than public transport


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