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DJ Drewman

What Spark Plugs To Use?

22 posts in this topic

So after looking through the partly filled service book on my newly aquired Focus 2.0L Petrol Focus and doing an oil change today I'm thinking that it's possible that the spark plugs are due for replacement.

After looking for a while on the FOC forums, I couldn't find an answer to "What would be a good set of spark plugs to give a good performance/economy".

I came across this thread [LINK] on another website (sorry for digressing off this wonderful site) which basically states that using the 'Autolite AR103' may be my best bet, but it seems to be an american make and not readily available in the UK.

Can anyone suggest a good substitution for this type in the UK. I think I'm looking for a copper plug that has a groove cut in the electrode and the electrode is nickel plated.

FYI 2.0L Duratec HE Petrol engine 2006.

Your recommendations please. ;)

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Bosch Super Plus are very good spark plugs, never had a problem with them.

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idk i only have glowplugs :)

+1 for bosch

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You're basically split between Bosch, Champion and NGK seeing as they're the only really prominent plugs in the UK.

Just go for whichever are the best rated in the correct size range.

Must admit that the Bosch Super Plus do get a good rating though.

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Bosch are what ford use its what i use and as above they are good plugs ford sell them quite cheap as well just remember they say pregapped but thats old gap sizes ypull need to gap them to 1.0mm

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Bosch are what ford use its what i use and as above they are good plugs ford sell them quite cheap as well just remember they say pregapped but thats old gap sizes ypull need to gap them to 1.0mm

Are Ford really using Bosch now? Its been a while since I've owned a petrol Focus but they always used be NGK. The original plugs were always Motorcraft but they were rebranded NGK's. I would personally stay away from Champion, having had some bad experiences with them in the past.

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Bosch are what ford use its what i use and as above they are good plugs ford sell them quite cheap as well just remember they say pregapped but thats old gap sizes ypull need to gap them to 1.0mm

I had a look online and frankly I'm really confused. I can't work out if I'm meant to use the +39 size or +46 (on the Bosch Super Plus) I just can't get a definitive answer what plug I should use :/

The Online Ford Parts site, says I can have a set of 4 (using my VIN) for £35 + VAT - really????

So assuming I'm going to go down the Bosch Super plus route, can anyone tell me what size I need.

(Once again 2.0L Petrol Duratec HE engine 2006 model)

Secondary to that I'm thinking of setting the gap to 55thou (which if my conversion is correct is around 1.4mm) as from the american thread I linked in my first post [LINK AGAIN] it seams to be the best gap for performance/economy - can anyone confirm that for me?

Thankies in advance.

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I had a look online and frankly I'm really confused. I can't work out if I'm meant to use the +39 size or +46 (on the Bosch Super Plus) I just can't get a definitive answer what plug I should use :/

The Online Ford Parts site, says I can have a set of 4 (using my VIN) for £35 + VAT - really????

So assuming I'm going to go down the Bosch Super plus route, can anyone tell me what size I need.

(Once again 2.0L Petrol Duratec HE engine 2006 model)

Secondary to that I'm thinking of setting the gap to 55thou (which if my conversion is correct is around 1.4mm) as from the american thread I linked in my first post [LINK AGAIN] it seams to be the best gap for performance/economy - can anyone confirm that for me?

Thankies in advance.

You should be fine with this here

http://www.eurocarparts.com/ecp/c/Ford_Focus_2.0_2006/p/car-parts/car-service-parts/regular-service/spark-plugs/?408772240&1&45d0c7c503a2c30c65fbd177abf33f4ad30e8845&000301

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I

Thanks Eliaskok, I did look here and I queried it because a) the price [per plug?, lower down it states fitted quantity: 4, which is correct?] and the fact it states just 'Bosch' not 'Bosch Super Plus'

I found these [LINK] which if this is the correct plug, seems a great price for 4. It looks like the same spec, 17.5mm thread length

Your thoughts?

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1.4mm will eat up coil packs give lumpy idle thats why ford set it to 1.0mm i wouldnt go higher as its not good

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Agreed, larger gap equals larger spark which means higher draw from the coil.

Higher draw causes shorter coil/ht lifespan.

Best sticking to recommended specs.

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I'v always done Zetec/e to the Haynes manual (1.3mm) (How cold it is here the smaller gap cant really hurt) lol

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I'v always done Zetec/e to the Haynes manual (1.3mm) (How cold it is here the smaller gap cant really hurt) lol

Haynes manual is not subject to ammendment. Ford specify 1.0mm. If you use 1.3mm it will eat your leads and coilpack.

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I

Thanks Eliaskok, I did look here and I queried it because a) the price [per plug?, lower down it states fitted quantity: 4, which is correct?] and the fact it states just 'Bosch' not 'Bosch Super Plus'

I found these [LINK] which if this is the correct plug, seems a great price for 4. It looks like the same spec, 17.5mm thread length

Your thoughts?

I think is the super plus but am not sure. The other link you have sent me are also correct part for your car and the price is good but you can find better one.

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So I nipped out and bought a set of Bosch Super Plugs (No 46 for my engine). I also bought a Haynes Manual whist I was at the shop.

The plugs came with a 1.1mm gap from the box, I've increased it to 1.2mm so I get better performance/economy.

As it's fairly easy to replace the coils I was looking at cost LONG TERM. Here are my rough thoughts/calculations.

So say the coils only last 25,000miles (which I would expect to be very low, and probably would last double that, but for the purpose of my calculations....) and by increasing the gap I get an extra 2.5mpg better economy (Once again, it may be more or maybe less...)

So over 25,000miles at 30mpg you use 834gallons. Over 25,000miles at 32,5mpg you use 769gallons, that's a 65gallon saving.
65Gallons at 1.30p/litre equates to £383. (65 x 4.54 x 1.3)

The coils cost around £100 - £120 to replace. So even by taking the larger figure off the saving (383-120) You still have a saving of £263 over the life of the coils IF they last only 25,000 miles.

So looking at the bigger picture, I would think that the smart thing would be to have a slightly bigger gap (than the standard 1.0mm that Ford recommend), as the long term savings are possibly massive.

Please note, I have NO basis to the figures above, but have put in reasonable assumptions that may be fiction but maybe not that far from fact!

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genuine coils are £35 quid from ebay and also made by bosch all ford m k2 and 2.5 use bosch plugs coils and leads as standard at 1.3mm the foci had misfire and coil pack problems ford reduced the gap to 1.0mm and its never changed since for that very reason 1.2mm will not do much it may give a poor or a miss at idle as the gap will increase over time given a bigger gap can eat coils in 10k miles youre figures are way out but if youre happy with 1.2mm go for it personally ive had the 1.3mm and it was a pain in the rear with misfires rough idle etc and yes bosch super plus are the plugs fords are just rebranded

http://www.ebay.co.uk/itm/FORD-FOCUS-1-8-2-0-BOSCH-COIL-PACK-SPARK-PLUGS-05-/280644104412?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4157b130dc

genuine ford coil with fomoco part number on it

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Arthur, I appreciate your comments :)

I'm going to give it a go with the 1.2mm gap, if I start having problems with idle etc, I'll take a look at the state of the plugs and maybe reduce the gap. At the moment it's sweet as a nut, but of course this could change. The Bosch plugs I put in looked very different to the Ford plugs that came out, god know how old there were as well maybe 3+ years, quite possibly the reason for the massive difference.

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My 2010 1.6 ti-vct focus had NGK TR5B-13 from the factory. Factory gap of 1.3mm on those plugs. I replaced with the same ones and have no issues with rough idle or misfires.

Sent from my Nexus 5 using Ford OC mobile app

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the 2008 on HXDA HXDB engine code has a ngk coil pack and plugs 2004-2008 has the bosch plugs and leads dont know wh they changed the mk1 used ngk and they were always a pain with coil failures due to the 1.3mm gap the mk2 with the bosch doesnt suffer from the coil pack issue it doesnt happen stright away ide ask ford if its been changed as the 12.3mm gap was causing the coil packs and leads to fail early causing the misfires etc ford have a tsb where its stated its reduced to 1.0mm to prevent this any dealer will tell you if its been changed even the bosch are pregapped at 1.3mm but ford took them out and regapped them at 1.0mm as thats what its meant to be

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the 2008 on HXDA HXDB engine code has a ngk coil pack and plugs 2004-2008 has the bosch plugs and leads dont know wh they changed the mk1 used ngk and they were always a pain with coil failures due to the 1.3mm gap the mk2 with the bosch doesnt suffer from the coil pack issue it doesnt happen stright away ide ask ford if its been changed as the 12.3mm gap was causing the coil packs and leads to fail early causing the misfires etc ford have a tsb where its stated its reduced to 1.0mm to prevent this any dealer will tell you if its been changed even the bosch are pregapped at 1.3mm but ford took them out and regapped them at 1.0mm as thats what its meant to be

My coil pack is bosch. If you look on the various sites /catalogues for the Mk2's it shows a 1.0mm gap pre 2008 and a 1.3mm gap post 2008.

Sent from my Nexus 5 using Ford OC mobile app

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After sending several emails to Bosch asking if I could get Bosch super4 plugs for the 1.6ti-vct (they weren't originally listed in website), they said hr78nx would be fine, and I've gotta say I think its performance worse. Tarnock ford say plugs should have HR7 MEV stamped on them and gapped at 1.2mm. On Bosch site it lists HR8 MEV gapped at 1.3mm. So maybe I'll try them but gap at 1.2mm. But a lot say iridiums are best, what's your views?

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