205 Gti-6 Spark Plugs

[r.u.sure 0]

Hi

 

I'm hopefully going to be changing the plugs on the '6' over the weekend and was wondering if somebody can tell me the correct torque setting for them please.

 

Thought I remembered reading somewhere they should be 12 Nm.

 

Many thanks

 

Dave

[rescue dude 0]

Never known anyone need to torque them, I've done them by feel for years.

 

The Gti plug's are 17 nm or 13 ftlb in old money.

[welshpug 1,657]

autodata says 25Nm, which wouldn't be far off 12 Lbft.

[rescue dude 0]

I tighten them till I feel the compression washer being squeezed then stop.

[jackherer 543]

http://www.ngksparkplugs.com/techinfo/spar....asp#installing

[hothatch 2]

http://www.ngksparkplugs.com/techinfo/spar....asp#installing

 

well done ! Torque - important ! Lots of things that should be torqued are never torqued. Sad really.

[pugpete1108 62 1 Cars]

i have always tightened mine to 'just pinched' and they have been fine

[large 33]

well done ! Torque - important ! Lots of things that should be torqued are never torqued. Sad really.

 

Yer, but when the lowest setting on your torque wrench is 750nm its a bit of a pita.

[hothatch 2]

Yer, but when the lowest setting on your torque wrench is 750nm its a bit of a pita.

 

Oi ! I don't just work on artics you know hahaha!

 

I've got a lovely little 3/8 wrench that goes from 10nm ! Cheek of it lol !

 

No seriously speakin I try and torque every thing if the informations availible.

[Cameron 16]

QT, not FT.

[Tom Fenton 1,542]

Granted torque is important in certain applications, but I cannot see it being THAT important in spark plugs, seeing as the manufacturers instructions on the box are basically screw in till it contacts, then plus 1/4 of a turn or whatever to crush the washer.

[hothatch 2]

Granted torque is important in certain applications, but I cannot see it being THAT important in spark plugs, seeing as the manufacturers instructions on the box are basically screw in till it contacts, then plus 1/4 of a turn or whatever to crush the washer.

 

Can cause pinking and detonation though.

[rescue dude 0]

Can cause pinking and detonation though.

 

 

How?

[rescue dude 0]

I'm certainly not knocking anyone who want's to torque plug's up but after a few year's building race car engine's I have learnt that the more highly tuned an engine, the more important it become's to get everything spot on.

 

For our roadgoing Pug's it is not that important.

[jackherer 543]

For our roadgoing Pug's it is not that important.

 

If you visit the 406 coupe forum you'll find they are into 'indexing' their spark plugs, i.e. tightening them, marking the body then removing them and changing the washers for a different thickness so they get all the electrodes pointing in the same direction...

 

FWIW despite posting the NGK torquing page earlier in the thread I fit plugs by giving them a final quarter turn, as Tom has said they even have this written on the box. However the OP asked for the torque figure and thats what they got

[jackherer 543]

How?

 

the NGK page has this claim:

Torque is one of the most critical aspects of spark plug installation. Torque directly affects the spark plugs' ability to transfer heat out of the combustion chamber. A spark plug that is under-torqued will not be fully seated on the cylinder head, hence heat transfer will be slowed. This will tend to elevate combustion chamber temperatures to unsafe levels, and pre-ignition and detonation will usually follow. Serious engine damage is not far behind.

 

An over-torqued spark plug can suffer from severe stress to the Metal Shell which in turn can distort the spark plug's inner gas seals or even cause a hairline fracture to the spark plug's insulator...in either case, heat transfer can again be slowed and the above mentioned conditions can occur.

[hothatch 2]

I'm not doubting that any of you know how to tighten a spark plug of course, a decent nip up is always enough on road cars.

 

But however in college in our technoligy lessons we learn the aspects of tightning torques on different components and the effects of being to loose or to tight they can have on them. This claim of detenation by ngk has also been tought to us in college. Why would ngk take the time to tell you this ? It doesn't have a positive effect.on their marketing.

 

But like you said doesn't make a major effect in road going veichles, but heat transfer is understandible I think.

[jackherer 543]

Why would ngk take the time to tell you this ?

 

To cover themselves in case you over/under tighten your plugs and blow your engine up, companies warn of all sorts of obscure risks so they can't be sued.

[Cameron 16]

Exactly.

 

I don't think they've quite worded that right though, the idea is to transfer heat out of the plug tip, rather than removing heat from the combustion chamber. I think their reasoning is that if you don't do them up tight enough only the first few threads will actually be properly engaged, so you have less surface area to transfer heat, whereas if you torque them up you get all the threads engaged fully and maximise the surface area. Maybe if you don't transfer the heat well enough the tip could get hot enough to pre-ignite the fuel, but I really doubt this could happen on anything other than turbo and race engines.

Edited April 3, 2010 by Cameron

[welshpug 1,657]

what the guys have described is exactly what the NGK guy said when I attended a brief seminar at MotorEx this week, even got an NGK mug

[r.u.sure 0]

Whilst I appreciate the fact that a lot of people are quite competent in most aspects of automotive DIY, sometimes, unfortunately I'm not I'm terrible with nuts and bolts or anything that has to be screwed in, I have a really bad habit of over-tightening things to an extreme and sometimes end up breaking something .....hence the question and the purchase of a torque wrench

 

Thanks very much for the replies everyone, much appreciated, 25nm it is.

 

 

Dave

Edited April 4, 2010 by r.u.sure