Hello, I'm changing the spark plugs on my zetec s and was wondering what the gap size needs too be on the spark plugs. 

Some are saying 1.3mm but others are saying 1.0mm

Most of the plugs for sale for my engine are 1.0mm but the Haynes manual is saying 1.3mm.

Im confused 🤯

Just searched through the on line manual and it doesn't even mention spark plugs.

1 hour ago, Bobr said:

Just searched through the on line manual and it doesn't even mention spark plugs.

Everything seems too contradict itself online. Ford are saying its both 1.3mm or 1.0mm and there are all sorts of numbers flying around. 

Would having a 1.0mm gap make any difference compared too a 1.3mm gap? 

42 minutes ago, Arkhangelsk1989 said:

Everything seems too contradict itself online. Ford are saying its both 1.3mm or 1.0mm and there are all sorts of numbers flying around. 

Would having a 1.0mm gap make any difference compared too a 1.3mm gap? 

what plugs part number you got for car what cc.

1.3mm will give bigger spark. Try 1mm first if car not running right increase to 1.3mm

10 minutes ago, st line x 140 driver said:

what plugs part number you got for car what cc.

1.3mm will give bigger spark. Try 1mm first if car not running right increase to 1.3mm

The plugs that have been recommended are ngk tr5a-10 which are the 1.0mm.

My car is a 1600cc zetec s. 

 

17 minutes ago, Arkhangelsk1989 said:

The plugs that have been recommended are ngk tr5a-10 which are the 1.0mm.

My car is a 1600cc zetec s. 

 

wrong gap symptoms - pre- ignition, detonation, fouling and poor fuel economy.

you got right plugs ngk say pre-set so good to go at 1mm

The prescribed spark plug gap for this type of engine is 1.2 mm

Initially the prescribed spark plug gap was 1.3 mm. However due to coil pack quality problems the prescribed spark plug gap was reduced to 1.0 mm. After the coil pack quality problems were sorted (many Years ago) the prescribed spark plug gap was changed to 1.2 mm.

Many suppliers of aftermarket spark plugs however still recommend the incorrect gap of 1.3 or 1.0 mm. 

A larger spark plug gap results in a fatter spark which ignites the fuel/air mixture more easily. However it also puts more stress on the coil pack. The prescribed spark plug gap is a compromise between the optimal spark and wear of the ignition components.

 

25 minutes ago, JW1982 said:

The prescribed spark plug gap for this type of engine is 1.2 mm

Initially the prescribed spark plug gap was 1.3 mm. However due to coil pack quality problems the prescribed spark plug gap was reduced to 1.0 mm. After the coil pack quality problems were sorted (many Years ago) the prescribed spark plug gap was changed to 1.2 mm.

Many suppliers of aftermarket spark plugs however still recommend the incorrect gap of 1.3 or 1.0 mm. 

A larger spark plug gap results in a fatter spark which ignites the fuel/air mixture more easily. However it also puts more stress on the coil pack. The prescribed spark plug gap is a compromise between the optimal spark and wear of the ignition components.

 

I have ordered genuine Ford motor craft ones which are 1.2mm and ngk tr5a-10 so I will test them out and see. Will the bigger gapped ones make the engine run smoother? 

10 minutes ago, Arkhangelsk1989 said:

I have ordered genuine Ford motor craft ones which are 1.2mm and ngk tr5a-10 so I will test them out and see. Will the bigger gapped ones make the engine run smoother? 

stick to preset gap tolerance will be +/- 0.05mm accuracy on gap - to big/small will effected performance/timing/efficiency.

4 hours ago, Arkhangelsk1989 said:

I have ordered genuine Ford motor craft ones which are 1.2mm and ngk tr5a-10 so I will test them out and see. Will the bigger gapped ones make the engine run smoother? 

There is a difference between the original FoMoCo (Ford Motor Company) spark plugs and the Motorcraft spark plugs.

The FoMoCo spark plugs are the spark plugs that are installed at the factory and usually also during a service at a Ford dealer. Depending on the type of engine these spark plugs are usually produced by NGK or Denso.

As an alternative to the original (FoMoCo) parts Ford owns the Motorcraft brand name. The Motorcraft Brand name includes aftermarket service parts that are a cheaper alternative to the original parts. The Motorcraft spark plugs for example are known to be rebranded Bosch spark plugs.

The 1.6 Duratec engine (Sigma engine family) was originally designed in collaboration with Yamaha. Back in the days these engines were factory fitted with NGK spark plugs. I have been using NGK spark plugs for these engines for many Years without a single problem.

Personally I would regap the TR5A-10 to 1.2 mm and use these spark plugs. These NGK spark plugs are pretty inexpensive. On my own cars I used to replace them every other Year.

feeler gauges what you normally use for measuring gaps

https://www.halfords.com/tools/hand-tools/saws-knives-and-blades/halfords-feeler-gauge-metric-and-imperial-16-blades-926667.html?istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istFeedId=367c5610-f937-4c81-8609-f84582324cd6&istItemId=rttxl&istBid=t&_$ja=tsid:94971|cid:865695754|agid:98356526289|tid:aud-297219198129:pla-930763854127|crid:419657927749|nw:g|rnd:813776749994621781|dvc:c|adp:|mt:|loc:9046274&gclid=Cj0KCQiAtqL-BRC0ARIsAF4K3WFx0D9D2IJmiPyZlRIVAj_dnpFi6jbtfgG3kmgYojsUkwt8ZuoCB5EaAhJXEALw_wcB

4 hours ago, FiestaForever said:

I found this item on ebay, which looks quite good.

Silverline 202148 Spark Plug Gap Tool, 0.5-2.55 mm/0.02-0.1 Inches: Amazon.co.uk: Car & Motorbike

 

No disrespect but that looks like its come out a christmas cracker! good for setting gap at angle due to taper.

Cheers for all of the replies. I will put the motorcraft ones in first and see how they go. If they aren't good then I will put the ngk ones in.

The motorcraft ones are pregapped to 1.2mm and the ngk ones are 1.0mm.

Hello, quick update on this thread, I changed the spark plugs and put the 1.1mm ones in. 

I have done a few hundred miles at least and have taken the plugs out too inspect and they look like this. Does this look alright? 

29 minutes ago, Arkhangelsk1989 said:

Hello, quick update on this thread, I changed the spark plugs and put the 1.1mm ones in. 

I have done a few hundred miles at least and have taken the plugs out too inspect and they look like this. Does this look alright? 

It seems the original Ford setting was 1.3 mm , but Ford found out it was putting a high resistance on the ign coil packs. So reduced the setting to 1.0 mm . 

1 hour ago, Robhonda said:

It seems the original Ford setting was 1.3 mm , but Ford found out it was putting a high resistance on the ign coil packs. So reduced the setting to 1.0 mm . 

Does the Condition of the plug look like its running alright? 

35 minutes ago, Arkhangelsk1989 said:

Does the Condition of the plug look like its running alright? 

 

35 minutes ago, Arkhangelsk1989 said:

Does the Condition of the plug look like its running alright? 

To me it looks like it’s running fine with the clean slightly tanned colour

I have added a description of plug condition from a NGK plug post