38 ES2 spark plug

That's the one specified by the manual although it's a short reach plug and the thread (at least in my 1952 ES2 with iron head) is long reach. I did have trouble with the short reach plug although I suspect that was more to do with carb settings etc.

I've now fitted an NGK B6ES (long reach) which seems to work very well.

My 1938 ES2 is definitely long reach. I have used an NGK B7ES for the last few years without problem.

The manual will say short reach but I suspect you'll find the thread is suitable for long reach. I was very doubtful that mixture of the correct strength would find its way into the little gap at the end of the thread.....

Previously ian_soady wrote:

The manual will say short reach but I suspect you'll find the thread is suitable for long reach. I was very doubtful that mixture of the correct strength would find its way into the little gap at the end of the thread.....

Justa word ofwarning regarding fittingalongreach plug after a motor hasbeenfitted withshortreach.

Clean the threadthrough to thecombustion chamber withataporsuitablymodifiedlongreachplug. Thebinding on oldcarbon depositshasbeenknow tosplit a castingthrough to thevalve insert. Keepthepistonat TDC then justblow the debrisoutwith anairjet....

Cheers

Jon

Jon's point is an excellent one.

The easiest way is to file longitudinal grooves in the thread of an old long reach plug and use that as a tap - well greased, and removed frequently, to minimise muck dropping in the combustion chamber.

Excellent.