Spark plugs trouble

[crankedup]

My 1925 Meadows OHV engined vintage car seems to be eating spark plugs. In around 1000 miles I have had to replace three sets. New plugs and all is fine, but within a few hundred miles or so a misfire sets in and each time I replace the full set of plugs (4) the engine runs fine again. I used to use Champion D16 but these are now obsolete so use the so called equivelent NGK AB 6.Any suggestions as to why I should be having this trouble please.

[Mr2Mike]

Anything obviously wrong with the old plugs? e.g. bent electrode, cracked insulator etc?

[rev-erend]

As Mike said - what do the plugs say ..

Colour ?

The easiest way to ruin a plug and cause it to misfire - is to give it the wrong mixture and possibly lots of oil to burn.

Linky to plug colour diagnosis :
http://www.verrill.com/moto/sellingguide/sparkplug...

[Driver888]

the tip on the plug sounds like its for some reason running at the wrong temp. Could be running too low and therefore its not burning of the carbon deposits which is causing it to misfire.

[tr7v8]

Correct ignition timing? This can damage plugs as well. A pick of a dead plug would be good as well.
It isn't running very weak on progression is it? This would make the plug work harder & die quickly.

[rev-erend]

I think he's forgotten this post .. or found his own answer.

[crankedup]

I'm back! thanks for replies. Its not an urgent situation so I confess it did slip my mind to come back. Still now I'm here, ignition timing is about right and the mixture is also about right. I do get
some popping back thru the exhaust when engine is hot but put this down to an leak in the exhaust system. Where two sections of pipe join together a gap exists in the sleeved joints. I've found a source for the old Champion D16 .

Can't post pic's up, must get my Son how to do that. If I see him soon I get him to post a pic.

Edited by crankedup on Friday 11th September 14:00