Electrode Gap On 1.6 Engine

[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

[PhillyFromTheWest]

I have a 2007 focus with the 1.6 ti-vct engine (115bhp), and on Bosch website it lists HR8MEV and on first part says gap of 1.3mm yet when you go and get full spec it says 1.2mm. It also lists HR8MCV and think it said 1.3mm. I emailed Tarnock ford who are a small independent garage and have been featured and used a few times by fast ford and they say it should be HRsevenMEV gapped at 1.2mm. But I was after the super 4 plugs and they weren't originally listed but Bosch said HR78NX would work and it was listed on their system, and shortly after they added it onto website. But the performance seems to have dropped so don't think they're correct. But if 1.2 is I between 1.3 and 1.0 so that sounds safe, and I trust Tarnock to the point that I live 60miles away but will try and only use them as I wanna burn down Allen ford of Swindon for ripping me off and not totally sorting problem I had.

 

only

[JW1982]

1.2 mm is the gap currently prescribed by Ford for all engines of the Sigma family (1.25/1.4/1.6 Zetec and Duratec).

 

The following spark plug gap sizes are currenty prescribed by Ford:

 

Focus MK2/MK2.5

1.4/1.6 Duratec and 1.6 Duratec TI-VCT = 1,2 mm.

1.8/2.0 Duratec HE = 1,3 mm.

2.5 Duratec ST/RS = 0,7 mm.

 

Focus MK3/MK3.5

1.6 Duratec TI-VCT = 1,20 mm (0,7-0,8 mm for LPG versions).

1.0 ECOboost = 0,7 mm.

1.5 ECOboost = 0,8 mm.

1.6 ECOboost = 0,8 mm.

2.0 Duratec HE = 0,9 mm.

2.0 ECOboost ST = 0,8 mm.

2.3 ECOboost RS = 0,75 mm

 

The 1,0 mm spark plug gap of the 1.4/1.6 Duratec engines was only prescribed by Ford for a short time. Unfortunately this gap size is still recommended by many spark plug manufacturers/suppliers while Ford changed it back to the original 1,3 mm after a very short time and later on to the current 1,2 mm. The (10 Year) old TSB's about this subject are also no longer valid. I always used the prescribed spark plug gap on these engines without any problems.

I guess the 1,0 mm spark plug gap myth of the 1.4/1.6 Duratec engines will be floating arround the internet for a long time.