Ruby mk2 spark plugs ?

[Joe eck]

I am currently running my Ruby on NGK b6hs plugs and occasionally it will soot its plugs .
I believe that this is not uncommon.


Is there any mileage in changing to a slightly hotter plug and, if so, what plug is recommended ?

Regards
Joe.

[Alan]

Try B5HS

[Hedd_Jones]

I recently did, on a RP with H/C head. I was suffering from poor starting due to fouling of the Champion L86.

Big improvement.

On another note, I've just bought a late Ruby. It has Champion J8's in it. They are hotter than the L86 im told.

[Joe eck]

Thanks to to all for the information.
I will try a set of B5hs.
Regards
Joe.

[Colin Morgan]

At the top of p232 of the 'Companion', Jack French says 'it is a habit of the '37 head to foul its plugs when the bores are a bit ropey'.  He then goes on to report that, unexpectedly, running with the sump full and long-reach soft plugs helps with this.  Is this borne out by the experience of others, please?  I tend to run with the sump oil below the full line, and occasionally have to swap the plugs about to keep them all looking sensibly biscuit-coloured.  

Colin

[Rogerfrench]

I must say, and not just out of loyalty either, that I found his advice about the plugs to be true. I guess they burn a bit hotter around the tips.
Can't remember about the sump level, but I had the problem on and off until I fitted a Supalloy head, then later a rebored block.

[Alan]

Well a B5HS is a softer plug. Not sure about using long reach ones - I’d be worried about the exposed threads in the combustion chamber, I’d think about turning off the excess thread, in the lathe. The NGK part number would be B5ES if you wanted to try.

[John Cornforth]

I wonder if "Long Reach" is a actually a mistranslation of "Long Nose" or "Projected Nose", a type of plug where the threads are the same length but the electrode assembly is designed to sit further into the combustion chamber.  This type enjoys some cooling effect from the incoming mixture.

I once took the Pearl to Jersey for a week's easter holiday.  The weather was unseasonably horrid, strong cold easterly winds and hailstorms.  Poor old car never really warmed up properly and misfired and fouled its Champion plugs.  A change to some softer NGK spares improved matters considerably.

[Hedd_Jones]

like this?. The one with the protrusion is a L87Y. Ive never tried it as I only have 1.

[David Stepney]

If memory serves me aright, the 'Y' suffix on Champion plugs denoted an extended nose. The idea was that the plug tip would extend into the hottest part of the flame and be less likely to foul.