1.2Tsi (CBZB) Spark plugs?

[wolfie]

Are these the correct plugs?

From ETKA 03F 905 600
A quick Google brings up NGK Iridium, IZFR6P7 I seem to remember my previous Vdubs having Bosch so just checking. Also anyone know the correct tightening torque? I assume it's always on a cold engine as the alloy becomes softer with heat and that can lead to a disaster...

[RUM4MO]

I tend to let the NGK website tell me which plugs I need for all my VW Group cars, I've written down a torque of 30Nm for new plugs and 24>28Nm for refitting used plugs for my Audi S4 which has an aluminium cylinder head and same diameter of thread as your 1.2TSI 8V. On the other hand, I have written down 22Nm for the plugs on my wife's August 2015 Polo 1.2TSI 16V - but that car has a flat thick copper washer as a seal, not the usual folded washer which collapses when tightened, so maybe once you have seen the new plugs you can work out which type of plugs or washer etc your new plugs have. Also, on that 2015 Polo, the top end of the plugs has been redesigned to better suit how these plugs contact the coils!

Edit:- on rethinking this, I'd use a torque of 25Nm for the plugs on the 1.2TSI 8V engine as that is what is quoted for the 1.4 16V engine which also has an aluminium head.

[RUM4MO]

Since I initially replied without offering a clear and definitive torque value, I looked around the internet and it seems if you run an American car, then NGK will have made it clear, as inputting the NGK plug type on my Audi S4, which is also sold in America returns torque values - but when I input your Polo's and my wife's Polo's NGK plug type nothing happens!
So I went back to a generic plug thread size and cylinder head material type look up chart and as both our different plugs have a 14mm thread size and are screwed into an aluminium head, the torque quoted is 25>30Nm - with the get out of jail covering note that "engine manufacturer's data should be accepted if different that that value given" - nice!

[wolfie]

Cheers.

I had a little look this morning and those are the numbers I found. I downloaded an NGK product catalog.

For an Alloy head using a 14mm threaded plug, with a flat seat type (which I think the TSi is) they spec.

25-30Nm (18.0-21.6lbs ft)

Taper fitting plug is quite a bit less at.
10-20Nm (7.2-15.5lbs ft)

I'll just air on the cautious side and aim at 25Nm, which sounds good to me as you've already been there, done that.

Might pick up a set in the morning. ECP have a reasonable discount this weekend with a set of 4 coming in at a little over £46 a set. I knew the iridium variety ran expensive. Opie oils are a tad cheaper but I'd have to wait for delivery. ECP is only 3 miles down the road.

I'm slowly but surely gathering the bits around me to service it myself this year.

[Jay-Jay]

Since my torque wrench starts from 28Nm, I've always torqued spark plugs at 28Nm on my engine.
So far so good!

I always screw them counter clockwise, untill the thread of the spark plug meets the first part of the female thread on the head cover (you can clearly hear a "tick" noise). Then, I start to screw them clockwise. In this way I avoid cross-threading.
But, even if I've always done like this, the weird thing is that, after applying the same torque to all 4 spark plugs, they end up not oriented all the same.
Some have the negative pole oriented to the top of the piston, others are oriented to the sky of the combustion chamber, some others are oriented in a mid way between the previous two ways.

I once found a picture of the downside of the head of a 1.2 TSI 8v and noticed the same weird thing.

The last time I had to replace sparkplugs on my engine, I wanted to look carefully at the new ones and I noticed they are not identical.
I marked a sign with a pen in corrispondence to the negative pole in a way I was able to see it after installing them on the head. In the end, I've been able to see they are not oriented all the same.

I suspect this could somehow affect performances and fuel consumption.
Something tells me that, if the negative pole is oriented to the top of the piston, it's better.

What do you think?

[RUM4MO]

I'd think or guess that this has been thought out and as the spark site/zone/area will always be close enough in the same place as it is in the centre of the plug, then that is good enough.

It just goes to show that even with mass production and that also means automated production, there are differences - or have you checked, or did you check, that all the 4 plugs were identical looking wrt to the earth electrode - or is it down to either the cylinder head individual holes depth or starting point of the thread rotation wise.

I bought a lower range torque wrench as soon as I started owning cars with aluminium cylinder heads, they come in handy for many other tasks when working on cars.

I also bought a higher range torque wrench as soon as I needed to remove and refit a wheel hub - that torque wrench, with its longer handle is now the only one I use for torqueing wheel bolts, with the longer handle it makes that sort of job so much easier, I don't know why I had not bought one like that a lot sooner - my original roughly 28Nm to 140Nm torque wrench is now basically redundant.

Edit:- also I'd think that the swirl of the incoming air will be mixing the injected fuel so the resulting fuel/air mix will be homogenised enough (if that is the correct type of word), so that any rotational differences are negligible.

Another Edit:- I wonder how you could explain the "track" that is showing coming from the injector to the inlet valve, strange or maybe not!

[wolfie]

Since my torque wrench starts from 28Nm, I've always torqued spark plugs at 28Nm on my engine.
So far so good!

I always screw them counter clockwise, until the thread of the spark plug meets the first part of the female thread on the head cover (you can clearly hear a "tick" noise). Then, I start to screw them clockwise. In this way I avoid cross-threading.

Now there's a thought! My torque wrench is pretty big, to be honest it only gets used to tighten the wheel bolts. I will have to check what the minimum is. Likewise I am also extra careful to not cross-thread the plug on alloy heads.

I doubt the orientation of the electrode would be that critical in a production car. Unfortunately production cars are built to a price and a quality that is "good-enough". I would imagine there are defined combustion zones and the electrode simply sits in that area. Judging by the colour of each cylinder they all look very similar, so I doubt any differences in position has a significant impact.

How come you had the head off??

Another Edit:- I wonder how you could explain the "track" that is showing coming from the injector to the inlet valve, strange or maybe not!

I noticed that. Maybe it has something to do with where the "fan" of the injector spray comes close to the chamber, so as the fuel ignites it leaves a residue. That is the direction they appear to point.

[Jay-Jay]

[...] as the spark site/zone/area will always be close enough in the same place as it is in the centre of the plug, then that is good enough.

[...]
I doubt the orientation of the electrode would be that critical in a production car. Unfortunately production cars are built to a price and a quality that is "good-enough". I would imagine there are defined combustion zones and the electrode simply sits in that area. Judging by the colour of each cylinder they all look very similar, so I doubt any differences in position has a significant impact.

Ok, I can live with that!

[...]How come you had the head off??

I never disassembled the head of my engine. The picture I posted above was taken from Google, searching for the head's part number.

[wolfie]

I never disassembled the head of my engine. The picture I posted above was taken from Google, searching for the head's part number.

Ah! I just thought maybe you had another project on the go...