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Do I need to gap new spark plugs?


spagball
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I've got new plugs for my 2005 1.6 petrol (see photo SP008SI are these the right ones?) , do I need to gap the plugs before installing? Also how much n/m should I torque them to? Thanks

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They normally come pre done. I've never had to do mine when fitting new. Also, don't torque them up. I've always done them up with a normal wrench until they feel right. You could snap them off in the head otherwise.

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1 hour ago, Gymfocused said:

They normally come pre done. I've never had to do mine when fitting new. Also, don't torque them up. I've always done them up with a normal wrench until they feel right. You could snap them off in the head otherwise.

I agree with this, just compare with your old spark plugs to make sure the look the same. If there's a difference then it may need checking. 

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Just realised changed plugs last March 2019 so only done about 9000 miles since.

Reason why I wanted to change I noticed the car was getting very sluggish on a journey after about 100miles acceleration was terrible so thought it was the plugs, a Dealer changed oil in January so maybe he put stupid oil in it I always use 5w30 Fully Synthetic any ideas? 

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1 hour ago, Gymfocused said:

They normally come pre done. I've never had to do mine when fitting new. Also, don't torque them up. I've always done them up with a normal wrench until they feel right. You could snap them off in the head otherwise.

Torque wrenches prevent that, by torqing them to the correct setting you avoid the risk of snapping, get a better gas seal and they come out easier next time. Basically hand tight with a socket then 1/8 to 1/4 turn max to compress the sealing washer. I usually put a dab of copper slip grease on the threads too. I've yet to have a stuck plug or snap one.

If you have a proper torque wrench this is a general guide without being brand specific. Probably suprise people how low the setting is for small plugs.

 

   
Plug thread diameter Tightening torque
18 mm           35 to 40N·m (3.5 to 4.0 kgm)
14 mm           25 to 30N·m (2.5 to 3.0 kgm)
12 mm           15 to 20N·m (1.5 to 2.0 kgm)
10 mm           10 to 12N·m (1.0 to 1.2 kgm)
 
   
   
   
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Ford originally specified a plug gap of 1.3mm for the Zetec engine. However, this gap was found in practice to cause problems with coil pack and lead failures. As a result, Ford issued a TSB on this and reduced the gap from 1.3mm to 1.0mm, which appears to have solved the problems which were occurring. I would invest in a gapping tool they are very cheap as you don't want to risk stressing the coil pack. 

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Car getting sluggish after 100 miles does not sound like the result of spark plugs needing replacement. But it is not clear quite what sluggish means. Was it only firing on 3?

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30 minutes ago, isetta said:

Car getting sluggish after 100 miles does not sound like the result of spark plugs needing replacement. But it is not clear quite what sluggish means. Was it only firing on 3?

Oh he would know if it was firing on 3 would sound like chitty bang bang 😂 

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Thanks for replays but do you think I should change plugs or just leave them? What else would cause a car to become sluggish not as responsive on accelerator as before- Car has always been fast and frisky since I got it at 60000mls but now seems dull, I have changed air filter at 80000mls plus done oil and filter changes every year since 2016

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Could be just getting used to the speed. Or maybe bad leads/coil pack If you have the new plugs no harm in trying. 

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On 7/18/2020 at 2:07 PM, F0CUE said:

Ford originally specified a plug gap of 1.3mm for the Zetec engine. However, this gap was found in practice to cause problems with coil pack and lead failures. As a result, Ford issued a TSB on this and reduced the gap from 1.3mm to 1.0mm, which appears to have solved the problems which were occurring. I would invest in a gapping tool they are very cheap as you don't want to risk stressing the coil pack. 

 

A spark plug gap of 1.0 mm is not correct for this type of engine.

The correct spark plug gap for all engines of the Sigma family (1.25/1.4/1.6 Zetec and Duratec) is 1.2 mm.

About 15 Years ago the 1.0 mm spark plug gap was prescribed by Ford for a very short time as an attempt to solve the high coil pack failure rate. Once this problem turned out to be caused by bad coil pack production badges the quality of the coil packs was improved and the prescribed spark plug gap was changed back to 1.3 mm. A few years ago the prescribed spark plug gap was changed to 1.2 mm which it currently still is.

The (15 Year) old TSB's about this subject that described the recommended 1.0 mm spark plug gap are no longer valid. I always used the prescribed spark plug gap of 1.3 mm and later 1.2 mm on many of these engines without any problems.

 

A bigger spark plug gap results in a fatter spark which ignites the fuel/air mixture more easily. High performance applications usually have bigger spark plug gaps. On the other hand a bigger spark plug gap also requires more energy and puts more stress on the coil pack. The prescribed spark plug gap is usually a compromise between performance and reliability.

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1 hour ago, JW1982 said:

 

A spark plug gap of 1.0 mm is not correct for this type of engine.

The correct spark plug gap for all engines of the Sigma family (1.25/1.4/1.6 Zetec and Duratec) is 1.2 mm.

About 15 Years ago the 1.0 mm spark plug gap was prescribed by Ford for a very short time as an attempt to solve the high coil pack failure rate. Once this problem turned out to be caused by bad coil pack production badges the quality of the coil packs was improved and the prescribed spark plug gap was changed back to 1.3 mm. A few years ago the prescribed spark plug gap was changed to 1.2 mm which it currently still is.

The (15 Year) old TSB's about this subject that described the recommended 1.0 mm spark plug gap are no longer valid. I always used the prescribed spark plug gap of 1.3 mm and later 1.2 mm on many of these engines without any problems.

 

A bigger spark plug gap results in a fatter spark which ignites the fuel/air mixture more easily. High performance applications usually have bigger spark plug gaps. On the other hand a bigger spark plug gap also requires more energy and puts more stress on the coil pack. The prescribed spark plug gap is usually a compromise between performance and reliability.

Ok I stand corrected 😂 thanks. 

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