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N52 spark plug and coil change how to

2003 - 2009, roadster, coupe, facelift
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groovy_hippy
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N52 spark plug and coil change how to

Post by groovy_hippy » Fri Sep 29, 2017 5:45 pm

Hi folks, there's probably a load of articles on how to do this, but though I'd share my experiences...

I have a 2007 N52 2.5i Z4 - it was having a few hiccups on acceleration at sub 2k revs. The job came in under £150.

1) Replaced all 6x coils with Bosch 0-221-504-470 - these are the revised version of what was in the car before (Bosch 0-221-504-467) according to Bosch's website. At the time of writing these are only about £17 each on Amazon - grab a bargain folks!
2) Replaced all 6x spark plugs with NGK iridium ILZFR6D11 - from CarParts4Less with one of their discounts, came in at just over £9 each.
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Tools you'll need:
6mm hex head for removing the plastic engine cover (might be 4 or 8, but if you've got a set you'll be fine)
M10 spark plug socket and ratchet
Torque wrench
A tea towel/rag, and some olive oil or such (I'll come to that bit ;)
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 ;-)

1) Whip off the plastic engine cover. You don't need to remove the cross brace :thumbsup:
2) Unclip each plug that goes into each coil. Pull the plug out of the coil and get it clear of the coil.
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3) Now for the tea towel or rag - hook it through the plastic clip and pull. Give the coil a roundabout wiggle if you fancy. They're quite hard to pull out but will come eventually with a champagne cork like pop. Repeat for all coils.
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4) Check there's no rubbish lying around in the bottom of the holes and undo the spark plugs, one at a time. Mine were quite tough but nothing too bad. Install each new plug after whipping out the old one, finger tight at this stage. You don't want to leave holes open into the cylinders for longer than you have to.
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5) Once all the new plugs are in, torque them up to 23 Nm +/- 3 Nm (in the BMW service manual).
6) Push the new coils into place - I started at cylinder 6 (near the bulkhead). They'll push into place with a small 'bump'. I found cylinder 4 to be the most tricky - it's next to the motor that looks after the variable valve timing (I think). Put a smidge of olive oil on the side of the motor to help the rubber coil slide past it if you're having trouble ;-)
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Put the plugs back in - push them as far as they'll go and then put the clip down (watch your fingers, they can bite!). Repeat for all coils. Get the plugs all the way in or you'll get a misfire (I did, ha!). Don't leave any 'gap' at the 'top'/towards passenger side, of the 'oval shape' hole in the top of the clip.
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7) Clear your tools up and fire it up - should be running happily! If you have an OBDII reader or Carly, perform a reset so the computer can re-learn the new coils and spark plugs.
8 ) Put the plastic engine cover back on and have a cuppa before taking it out for a spin!
Last edited by groovy_hippy on Sat Sep 30, 2017 7:40 am, edited 1 time in total.
Current ... 2007 Z4 Coupe 3.0si Sport | Manual | Alpine White | Black leather | Piano black dash
Intro to Zeds, now sold... 2007 Z4 2.5i SE Roadster | Manual | Stratus Grey | Red Leather | CDV delete | DLV backbox

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Ducklakeview
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N52 spark plug and coil change how to

Post by Ducklakeview » Fri Sep 29, 2017 6:08 pm

Nice write up Jess, has it cured your problems?

Mike

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groovy_hippy
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N52 spark plug and coil change how to

Post by groovy_hippy » Fri Sep 29, 2017 6:51 pm

Seems to have done Mike - certainly a bit snappier on acceleration now! I'll give it a few more trips before I'll know for sure. But, judging by the amount of cr@p on the electrodes on the spark plugs, and the corrosion on the coils it can't have made it any worse ha!!
Current ... 2007 Z4 Coupe 3.0si Sport | Manual | Alpine White | Black leather | Piano black dash
Intro to Zeds, now sold... 2007 Z4 2.5i SE Roadster | Manual | Stratus Grey | Red Leather | CDV delete | DLV backbox

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N52 spark plug and coil change how to

Post by Buckz » Fri Sep 29, 2017 6:55 pm

Ducklakeview wrote: Fri Sep 29, 2017 6:08 pm Nice write up Jess, has it cured your problems?

Mike
would like to know too :) As I sometimes experience a bit of weirdness low rpm..
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N52 spark plug and coil change how to

Post by groovy_hippy » Fri Sep 29, 2017 7:13 pm

I should also add that I gapped the plugs to 1.1mm as it says on the NGK website. I found a post on a US forum that said the imperial equivalent too, so that was good enough for me!
Current ... 2007 Z4 Coupe 3.0si Sport | Manual | Alpine White | Black leather | Piano black dash
Intro to Zeds, now sold... 2007 Z4 2.5i SE Roadster | Manual | Stratus Grey | Red Leather | CDV delete | DLV backbox

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N52 spark plug and coil change how to

Post by Steve84N » Sat Sep 30, 2017 12:20 am

It's the valvetronic motor that controls valve lift not timing. Basically it acts instead of a butterfly throttle body.
C63 AMG Estate 6208cc

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N52 spark plug and coil change how to

Post by Ducklakeview » Sat Sep 30, 2017 1:15 am

Steve84N wrote: Sat Sep 30, 2017 12:20 am It's the valvetronic motor that controls valve lift not timing. Basically it acts instead of a butterfly throttle body.
Erm, no it doesn't..

Mike

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N52 spark plug and coil change how to

Post by GuidoK » Sat Sep 30, 2017 2:10 am

Do you have pictures of what your sparkplugs look like (soot or coffee brown etc)

Steve84N wrote: Sat Sep 30, 2017 12:20 am It's the valvetronic motor that controls valve lift not timing. Basically it acts instead of a butterfly throttle body.
I think so too.
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N52 spark plug and coil change how to

Post by Steve84N » Sat Sep 30, 2017 5:11 am

Ducklakeview wrote: Sat Sep 30, 2017 1:15 am
Steve84N wrote: Sat Sep 30, 2017 12:20 am It's the valvetronic motor that controls valve lift not timing. Basically it acts instead of a butterfly throttle body.
Erm, no it doesn't..

Mike
Care to elaborate as erm, yes it does...

The VANOS does the timing and the valvetronic motor mentioned in the guide controls lift through the use of an extra eccentric cam as explained here: http://www.bmwblog.com/2016/07/25/valve ... le-system/
C63 AMG Estate 6208cc

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N52 spark plug and coil change how to

Post by groovy_hippy » Sat Sep 30, 2017 7:39 am

Well, whatever that motor has to do with valves, we're talking spark plugs and coils folks ;-) ....and here's the pictures of what I removed yesterday...

Mucky spark plug next to new one...
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Old coil - the new ones were bright silver inside but I didn't get a picture.....
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Current ... 2007 Z4 Coupe 3.0si Sport | Manual | Alpine White | Black leather | Piano black dash
Intro to Zeds, now sold... 2007 Z4 2.5i SE Roadster | Manual | Stratus Grey | Red Leather | CDV delete | DLV backbox

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N52 spark plug and coil change how to

Post by RyanB88 » Sat Sep 30, 2017 7:58 am

Nice write up, thanks!
Z4 now sold :(

Current - M235i :thumbsup:

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N52 spark plug and coil change how to

Post by Ducklakeview » Sat Sep 30, 2017 9:24 am

Steve84N wrote: Sat Sep 30, 2017 5:11 am
Ducklakeview wrote: Sat Sep 30, 2017 1:15 am
Steve84N wrote: Sat Sep 30, 2017 12:20 am It's the valvetronic motor that controls valve lift not timing. Basically it acts instead of a butterfly throttle body.
Erm, no it doesn't..

Mike
Care to elaborate as erm, yes it does...

The VANOS does the timing and the valvetronic motor mentioned in the guide controls lift through the use of an extra eccentric cam as explained here: http://www.bmwblog.com/2016/07/25/valve ... le-system/
Yes, the valvetronic controls the lift of the inlet valves, but it doesn't act like or simulate a butterfly throttle valve.
In other words, in normal driving, the “gas pedal” controls the Valvetronic hardware rather than the throttle plate.


Mike

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N52 spark plug and coil change how to

Post by Ducklakeview » Sat Sep 30, 2017 9:27 am

Ducklakeview wrote: Sat Sep 30, 2017 9:24 am
Steve84N wrote: Sat Sep 30, 2017 5:11 am
Ducklakeview wrote: Sat Sep 30, 2017 1:15 am

Erm, no it doesn't..

Mike
Care to elaborate as erm, yes it does...

The VANOS does the timing and the valvetronic motor mentioned in the guide controls lift through the use of an extra eccentric cam as explained here: http://www.bmwblog.com/2016/07/25/valve ... le-system/
Yes, the valvetronic controls the lift of the inlet valves, but it doesn't act like or simulate a butterfly throttle valve, the engine still has a butterfly throttle plate.
In other words, in normal driving, the “gas pedal” controls the Valvetronic hardware rather than the throttle plate.


Mike

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N52 spark plug and coil change how to

Post by Steve84N » 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.
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N52 spark plug and coil change how to

Post by jack07 » 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.
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