4 replies to this topic

[gumpy321]

Hi there,

I'm about to replace the spark plus in the car. What does Ford recommend the gap to be at with the new plugs? I'm getting conflicting information. Some are saying 1.3mm, others 1.0mm. Some are saying originally Ford made them originally to 1.3mm but this caused the coil pack to go faulty. Ford then solved the problem by making the 1.0mm.

So which is true? Do the original Ford Motocraft spark plugs come with a gap of 1.0mm or 1.3mm? The NGK's is was about to buy come with 1.3mm?

Thanks

[artscot79]

1.0mm they were originally 1.3mm however the gap proved to be too much and caused idle issues such as small missfires it is without a doubt 1.0mm i had ngk in at the pregapped 1.3mm when it was in for a service they told me the gap was too much and had adjusted them to 1.0mm

[FOCA]

Agreed, apparently the "fatter" spark (1.3mm) gave a more "comlpete" burn which was better for emmisions/ performance - if the ignition can cope with it

Unfortunately it put the ignition system under more stress (also, the gap gets wider as the plug wears)

the wider the gap, the higher the voltage/ power required to spark across that gap, also, its like lightning, it will find the easiest path, thats fine if the easiest pathe is the tip/ electrode on the spark plug, but not so fine if the easiest path is inside the coil packs, a crack and /or moisture on the ht leads, or the plug cap or down inside the spark plug, a narrower gap ensures the spark is delivered to the correct place, as well as putting the ignition system under less stress

As long as the tip/ earth is not touching the electrode, the spark plug will still work, "gapping it down" can "fix" faulty coil/ packs, ht leads etc (to a certain extent) by giving the spark an "easier" path to cross, but not such a "fat" spark, may affect performance

its not just the 1.6 engine, and not just Ford that had these "wide" plug - gaps, that caused all sorts of problems in the long run

Spark plugs are not nessesarily pre-gapped and its worth investing in feeler gauges and a gapping tool (not expensive) and checking them yourself

[gumpy321]

Agreed, apparently the "fatter" spark (1.3mm) gave a more "comlpete" burn which was better for emmisions/ performance - if the ignition can cope with it

Unfortunately it put the ignition system under more stress (also, the gap gets wider as the plug wears)

the wider the gap, the higher the voltage/ power required to spark across that gap, also, its like lightning, it will find the easiest path, thats fine if the easiest pathe is the tip/ electrode on the spark plug, but not so fine if the easiest path is inside the coil packs, a crack and /or moisture on the ht leads, or the plug cap or down inside the spark plug, a narrower gap ensures the spark is delivered to the correct place, as well as putting the ignition system under less stress

As long as the tip/ earth is not touching the electrode, the spark plug will still work, "gapping it down" can "fix" faulty coil/ packs, ht leads etc (to a certain extent) by giving the spark an "easier" path to cross, but not such a "fat" spark, may affect performance

its not just the 1.6 engine, and not just Ford that had these "wide" plug - gaps, that caused all sorts of problems in the long run

Spark plugs are not nessesarily pre-gapped and its worth investing in feeler gauges and a gapping tool (not expensive) and checking them yourself

Thanks for the explanation. Also thanks to Arthur. You've put my mind at ease.

[artscot79]

no probs like i say i bought my ngk at the supposed pregap of 1.3mm assuming this was correct till the ford master tech told me ford changed the gap to 1.0mm at the time of the mk1 focus coil pack issues these gaps have been kept to all newer focis as well like you say theres lots of conflicting info for what should be a simple answer