N52 spark plug and coil change how to

maxman · Post by **maxman** » Sat Sep 30, 2017 12:10 pm

Very good write up.

groovy_hippy · Post by **groovy_hippy** » Sat Sep 30, 2017 1:52 pm

jack07 wrote: ↑Sat Sep 30, 2017 11:40 am Good 'how to ' Groovy.I would mention a good precautionary dab of anti seize compound on the new plug threads to help with future removal and avoid pulling thread material from the cylinder head at next change.

The use of anti-seize compound seems to be up for debate - the BMW workshop manuals don't say use it, but then other places do say use it...I didn't (neither my or my other half have even used it on our cars), but I'm not going to criticise someone who does use it. It's a bit like buttering your toast if you're having jam on it if you ask me

MACK · Post by **MACK** » Mon Oct 02, 2017 12:40 pm

Steve84N wrote: ↑Sat Sep 30, 2017 9:45 am You misunderstood me, whilst it doesn't actuate a butterfly valve it does the same job as one in that it regulates air intake.

The butterfly throttle plate is purely there as a back up but unless something goes wrong the valve is always wide open. In other words it's not regulating air intake, the valvetronic motor is.

The downside of a throttle valve is high pumping losses at small openings. By having atmospheric pressure right up to the inlet valves this problem is removed. Then when you want a small amount of power valvetronic opens the valves with just a small amount of lift letting only a small amount of air in. The upside is it's not sucking through a straw so to speak. The efficiency benefits of valvetronic diminish with larger throttle applications and actually it becomes less efficient at very high revs due to the stiffer valve springs required.

Given that the valvetronic motor acts on the eccentric cam that adjusts valve lift that controls air intake the motor is acting instead of a butterfly valve and performing the same role.

+1 great explanation above. The fact it has a back up butterfly valve seems to often cause confusion/ catch people out.

GuidoK · Post by **GuidoK** » Mon Oct 02, 2017 1:28 pm

Steve84N wrote: ↑Sat Sep 30, 2017 9:45 am You misunderstood me, whilst it doesn't actuate a butterfly valve it does the same job as one in that it regulates air intake.

Exactly, both the butterfly valve (throttle body) on a normal car and the valvetronic system on this engine serve that same purpose.
It is the essence of valvetronic.

The n52 has an extra butterfly valve afaik to regulate the esp system (just as for instance some m52 engines have dual throttle bodies, one cable operated for throttle, one electronic for esp/act) and I'm not sure but I think its a mandatory european safety construction in that its automatically shut when the system loses power (at least thats what I got at some point for explaining why all electronic throttle bodies are spring loaded). If the valvetronic motor would loose power, I think it would stay in its position it was last in and not automatically close the valves.

groovy_hippy wrote: ↑Sat Sep 30, 2017 7:39 am
Mucky spark plug next to new one...
IMG_8431.JPG

I know they're different type/brand sparkplugs, but does it seem that from the old one the tip has melted away a bit? (have you measured the gap to see if its different?)
Or maybe the new one just has a longer point on the tip.

Steve84N · Post by **Steve84N** » Mon Oct 02, 2017 4:57 pm

I thought it was normal to see the tip wear down slightly and that's one of the reasons why they need replacing?

GuidoK · Post by **GuidoK** » Mon Oct 02, 2017 5:31 pm

^maybe inevitable but not normal imho.
The plugs are rated for 50k miles+ I think and should last a lot longer for a tip to melt away in such manner that it increases spark gap size measurably.
Normally the sign of wear is that on the tip the edges round off a bit (barely visible), but even that shouldnt happen within 50k miles.
The gap is critical and shouldnt change.

But my experience is mainly with bosch.

Steve84N · Post by **Steve84N** » Mon Oct 02, 2017 6:00 pm

One thing is for sure, they're much better now after being replaced.

jack07 · Post by **jack07** » Tue Oct 03, 2017 6:33 am

groovy_hippy wrote: ↑Sat Sep 30, 2017 1:52 pm
jack07 wrote: ↑Sat Sep 30, 2017 11:40 am Good 'how to ' Groovy.I would mention a good precautionary dab of anti seize compound on the new plug threads to help with future removal and avoid pulling thread material from the cylinder head at next change.

The use of anti-seize compound seems to be up for debate - the BMW workshop manuals don't say use it, but then other places do say use it...I didn't (neither my or my other half have even used it on our cars), but I'm not going to criticise someone who does use it. It's a bit like buttering your toast if you're having jam on it if you ask me

The first time you pull cylinder head material out on the plug thread,you will convert!

groovy_hippy · Post by **groovy_hippy** » Tue Oct 03, 2017 7:44 am

It's fair to say the old plugs weren't looking too well.
The electrodes were worn down yes and the gaps were bigger than the ones that went in. The old plugs just didn't look very happy IMO. They were almost 80k miles old though... as far as I'm aware, they'd never been changed prior to my ownership, and I've done nearly 40k in it....

The car is much snappier now and looks to have slightly better fuel consumption so far...probably closer to how it came out of the factory!!

saseinlinie · Post by **saseinlinie** » Fri Oct 06, 2017 8:55 am

Regarding this part:

If you have an OBDII reader or Carly, perform a reset so the computer can re-learn the new coils and spark plugs

Is there a guide on this anywhere ? I have a cheapo OBD reader..

Thanks

ph001 · Post by **ph001** » Fri Oct 06, 2017 9:38 am

saseinlinie wrote: ↑Fri Oct 06, 2017 8:55 am Regarding this part:

If you have an OBDII reader or Carly, perform a reset so the computer can re-learn the new coils and spark plugs

Is there a guide on this anywhere ? I have a cheapo OBD reader..

Thanks

There is no specific adaptation for coils and plugs as far as I am aware. I know there is for knock, octane and general fuel trims (long term and short term) but I don't think it would be necessary to reset anything after changing coils and / or plugs.

Scooba_Steve · Post by **Scooba_Steve** » Fri Oct 06, 2017 9:41 am

I've never seen anything specific to plugs and /or coils, but it is possible to reset all adaptations.

ph001 · Post by **ph001** » Fri Oct 06, 2017 9:44 am

Scooba_Steve wrote: ↑Fri Oct 06, 2017 9:41 am I've never seen anything specific, but it is possible to reset all adaptations.

Not through Carly though. I have a feeling he was talking about clearing fault codes perhaps, which of course means the re-learning thing is a bit of a nonsense.

Scooba_Steve · Post by **Scooba_Steve** » Fri Oct 06, 2017 11:55 am

I didn't know Carly couldn't do adaptation resets.

saseinlinie · Post by **saseinlinie** » Fri Oct 06, 2017 3:04 pm

Something to gap the plugs with (pliers and hammer) and a feeler gauge. Google how to do this, and if you wreck your plugs don't blame me

also not sure about the above, afaik the spark plugs(NGK ILZFR6D11) come ready to be installed, is it really necessary to hammer them

?

https://www.ngk.de/nc/en/product-finder ... 6D11/1867/

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