58 plug in slot head

[Alexlib]

Afternoon, I have a G3 with a competition top end having the plug in the slot, I notice that the alloy head has the casing marks from a side entry plug, has anyone fitted a second plug to improve starting ?

[dave16mct]

Not yet but I have thought doing it on my 57 18CS! I think it would be relatively easy to do (I've even got the tap) but I'm frightened of it cracking between plug hole and valves. What plug are you using? There was a 3 or 4 electrode plug for the comp bikes with the slot. But it's obsolete now. I'm just trying one at the moment but it still seems hard to start and I've no idea what grade it is. I've even side-gapped an N9Y and used that. How easy/hard is yours to start?
Dave

[Alexlib]

Hi Dave
I have a ngk b7es at the moment .
From cold it takes about 10 kicks , five then wait for another minute and another five .
When it’s warm it is unpredictable, it seems to like being tickled twice and then chancing upon the right cold start lever setting.

[dave16mct]

Hi Alex,
I've just seen a G80CS on Car & Classics for sale in Germany for 7700 Euros. If you look at the close up of the engine you can clearly see that a plug has been fitted in the normal position and you can see the original centre plug behind it. I wonder if anyone else has done it?
Dave

[ajsph]

on my 1959 roadgoing 18CS, I used NGK B8ES with an extra copper washer fitted, starting was never an issue, first or second kick, it has 8.5 Piston and HS cams.
regards Poul Hansen
Denmark

[Alexlib]

Thanks all , I will try a multi earth plug first, I have an ngk B7ET multi earth on order, I don’t think the heat range is sensitive, I did try an 8 but there was no improvement @dave16mct, I looked at the German bike and can see what you say, but as you suggest if it is not a tried and tested mod there may be risks, I wonder if Ken DeGroome might know?

[Alexlib]

IMG_4960.png

Interesting the German advert only has one plug connected