The man who seen 1,000s of real spark plug change in MB workshop...have SPOKEN . Thank you Joe.

 

Very good. Reading glasses always on.

If you have MB plugs and torque to 23Nm then you can sleep easy. No marking of anything is needed.

Good point Joe makes about stratified and homogenous charge engines. The M276 is built with both types of ignition.

 

Yes E400 Sedan in USA 2015 prior we had E550.
I do like the E400 for cruising.

I thought Stratified mode was done outside USA and not in engines destined for USA.
It is mainly a Europe thing and...
I like to say it was due to available fuels?? - Probably wrong so be gentle...

I read that somewhere... Dayum I forget where...probably this forum but think it was on MB docs.
Probably on here somewhere but having nothing to do with Indexing instructions.

Time for more coffee

 

Some of the high economy modes are disabled due to emissions differences, the lean burn creates NOx levels that exceed US regulations so the lean modes are disabled here. But they don't build a different mechanical engine for that, we just have the options turned off in the M/E.

 

This one explained the stratified mode. Start at 3:00

 

I have changed the plugs today using genuine MB plugs and torqued all to 23nm
i marked the plugs to check orientation after reading all the advice on here.
The angles are all different and i want to check the acceptable margin of error
Can anyone please confirm that when looking into the spark plug hole, assuming 0 degrees is at the 12 oclock position, what is the utopia point that the open spark should point to at the torqued setting ie is it 6 o'clock? Or 12 o clock (and i can then assess how far im in/out of the specified 45 degree perameter. Many thanks

 

The search function will find it.

Posted on this site many times.

https://mbworld.org/forums/attachmen...g-indexing.pdf

 

Lessbay,

First you mark the plug L bent ground. Like mine. Take it as though as the plug zero.



Now, where the plug is and where the injector is :

So as above, if you are installing the spark plug, its physical position is 6 o'clock or below of the injector.


The MB document photo is a cylinder head placed on a bench, and that is UPSIDE-DOWN of what you are seeing in real life when doing plug install.
Remember, spark plug is UNDER the injector, not ABOVE.



BELOW is the correct way to read MB document ( but in a mirror way , as in left becomes right side and vice versa), in respect to how we are seeing the 2 components position when engine is in front of us totally assembled.




A wide angle engine and spark plug hole view



So you want your spark plug L ground MARKING to be at 6 o'clock as best.
5 or 7 o'clclok very good too.
4:30 and 7:30 is the maximum.

12 hour round analog clock interprepation = 1 hour is worth 30 degrees.
MB allows +-45 degrees from perfect alignment they seek which we call it PERFECT 6 o'clock or 180 degrees ( plug L ground) in respect to injector as ZERO or 12 o'clock.

Have fun..............

 

Yeah, indexing, totally. Interestingly enough, there is no mention of indexing in the WIS "Replace Spark Plugs" document, only a 23Nm torque value is given. So from a technician's perspective, he is aware of indexing, and he is also aware that 23Nm is going to get you in the green zone. Techs don't have time to waste marking plugs. Have you ever seen a Benz dealer-marked plug?

 

+1

OEM plugs from the dealer + 23Nm = done

 

I want to share some humor.

As per my calculation to be PERFECT spark plug to injector alignment based on my current female thread for the spark plug at the cylinder head and its resulting "alignment" value.....
I had to get a 1.2mm copper washer.

So I looked online locally and got a 1.2mm copper washer.
When it arrived, it was only 0.95mm .... , I am not suprised though because cheating on thickness is common for locally manufactured metal and more so if
the metal is as precious as copper. So I asked the seller, do you have a 1.5mm thickness version, hoping that the manufacturer will cheat me again and I get 1.3m as a result....
Well, seller said no 1.5mm.

So I turned to China, AliExpress.
I bought a few outer diameter sizes for the M12 ( M12 is our spark plug outside diameter ) M12 x 16mm OD and M12 x 18mm OD and both at 1.5mm thickness. There is no 1.2mm thickness version.
I was hoping to be cheated .............. ha haha.
Few weeks later the copper washers arrived from China. It was honest goodness 1.5mm thick and in fact 16.5mm OD for the 16mm one ....
I laughed to myself, why I was not cheated when I wanted to be cheated, but I was cheated by a seller from BangGood , 1 product only, when I dont want to be cheated ..... LOL

Anyway, I go the manual way. I got someone to slowly thin down the 1.5mm copper washer to 1.2mm.
After my long trip it should be ready, 6 pcs. I bought 20, so I can do various thickness.

I have to remove my plugs anyway later, as I want to do a few things about 2 months from now:
01. Measure all my cylinder compression, using a clone version of Pico WP500X pressure transducer.
02. Clean my intake valves. Not wallnut blast method, but very manual tooth brush kinda of cleaning....something like that.
03. Inspect my PCV system, its oil separator.... how dirty it is and clean it.
04. Replaced all 4 cam phasors which I already bought and supposedly it will leak at the connector and send engine oil into wiring assy and up to engine comnputer...... in the near future.
05. Got to remove aftercooler anyway, so clean them cooling fins with a degreaser.
06. Change coolant, but the turbo circuit only. This coolant circuit works VERY HARD.
07. Got to remove throttle body anyway, so clean it well.
08. If I can get the suitable balloon plugs for exhaust pipe and turbo-s intake, I want for the heck of fun to smoke test my intake system to 1 psi. See any super small leak, if any, after new gaskets of intake manifold installed.
09. Test again all my cylinder compression, using a clone version of Pico WP500X pressure transducer....see any benefit of the intake valve cleaning.
10. Try to get closest 6 o,clock INDEX as possible for all my spark plugs with the DIY 1.2mm copper washer.

 

Thanks so much my confusion has ended! I had marked the plugs with the marking indicating the open spark and not the L bend hence why I asked the question
i have 3 plugs pointing out if the "good zone" so will try to swap around and reinstall to see if that helps

i used the MB plugs and a good calibrated torque wrench and marked the plugs to check their orientation
3 were out by quite a bit at 23nm

i would like perfection if possible but looks like if swapping around doesnt help will need some copper washers.
Appreciate replies of "just use MB plugs and 23nm" but as detailed as per other members, my plugs simply are not lining up and my particular engine does require indexing so need to get it right if i can
This pics helped many thanks

 

Yeah, that's funny, except for all the extra work and expense. Glad you can laugh about it though

 

^ This is incorrect. I've proven it on multiple MB cars.

OEM plugs from the dealer, torqued to 23nm (17 ft lbs) and you'll not even get close.

I have the V8 version of that same engine, and mine were all clocked at 7 O'clock. (The original plugs however on my 2012 were all at 11:30, but MB changed the plugs heat range after that year. I just did a 2014 with the original plugs still in it, and those were all aimed 90 degrees or more to the left. NONE in spec,.. FROM THE FACTORY !

I bought MB plugs from the dealer, A set of MB plugs from FCP Euro and a set of the exact same model number plugs from Bosch. They all clocked the same,... at. 7 O'clock.
https://mbworld.org/forums/w212-amg/...ndexing-2.html

I also bought lots of sets of copper washers. Only found one set that were actually 1.0mm, and none that were anywhere between 1 and 1.5.,.. and with those I was able to get a couple barely into acceptable range.

I ended up having to sand down stock ones to 1.15mm - 1.25mm, and then put a bevel back on them so they'd have some "crush" to them.

 

It's not at all "incorrect", and the fact that you're using sand paper to sand spark plugs to adjust depth before installing them tells me you have no idea what you're talking about. Literally nobody but you, since the beginning of time, has ever sanded a spark plug for that purpose. Your information needs to be facebook-level fact-checked censored and cancelled.

 

Easy there.

Not the plugs, the copper washers.

Simple in concept, but time consuming, and it requires good measuring equipment to make sure you've gotten them even.

The other method would be to put indexing washers underneath the copper ones. But of course you're pulling the tip of the plug OUT of the cylinder a bit.

But yeah, you can either shave down the washer to go IN 1/3 of a turn, or use indexing washers to move them out 2/3 of a turn..

My point was,... anyone that tells you that simply using OEM plugs torqued to spec will get them indexed properly has simply never checked their results like I have and the OP did.

The OEM plugs made after early 2012 do not index the way the earlier ones did.

 

Ok, my bad. I understand your logic. Indexing is important, but I still think a mountain is being made out of a molehill here. I am not aware of, and therefore don't believe there are hundreds of thousands of misfiring Mercedes (or any other DI motor, for that matter) out there because a plug was a few degrees off. Getting super duper scientifical about a non-issue here. The machining processes, proper components, and adherence to factory maintenance and repair information will result in a normally operating vehicle. And this is across the board, for any DI engine. If manual marking and clocking a plug was necessary, the football teams of lawyers who work for the manufacturers would have made sure that information was absolutely clear in the documentation for the vehicle.

 

I don't disagree that it may be mountain>mole hill... the "issue" is MB's own documentation.

One states the need for it, so as far as to show examples of non-adherent OEM/aftermarket plugs. A WHOLE document devoted just to this singular point. However, the actual repair procedure only has you torque the spark plugs which are intended to index "correctly".

Well, what is "correct"? A few users have noted that using OE plugs, torqued per spec don't align with the first document that shows "proper" plug position. So at the end of the day, either:

• first document isn't correct or is out-dated
• tolerance is actually greater than suggested
• plugs aren't correctly machined
• users engines are somehow different (thread machining)
  

 

We can't know for sure.

That document claims that it is very critical. Critical = super important, and very critical = very super important, which seems pretty important.


BUT,.. it's also about using the correct heat-range plugs AND indexing them correctly. And it doesn't state how important each of those components is. Is the heat range 90% of it? Or the indexing? Are they 50/50 in importance? We don't know.

But a lot of people here like to do things as best they can,... so hence the thread.

Personally,.. I've concluded that it's the plugs.

The plugs that Bosch is making these days, either with their own branding on them or as sold through the Merc dealer, FCP Euro etc,.. simply do not clock (index) the same as the plugs that came in our 10+ year old cars.

The plugs that came in my 2012 car originally clocked perfectly,... and the Bosch and MB plugs I bought last Fall aren't even close. And the crush washers are 1.5 mm on both, and of course the threads in my cylinder heads didn't change while I was swapping plugs.

 

To add some more substance to the discussion, data is always a good thing.

For users marking their plugs, and correcting each plug for indexing via sanded washers or other method, please provide the following for each plug - very important:

Vehicle VIN:
Engine number (not model):
Spark plug manufacturer and part number:
Torque wrench manufacturer and model:
Torque applied:
Indexing degrees using MB spec (0 represents perfect indexing per MB spec): + degrees means out of spec in the clockwise direction when looking at the spark plug from above

If a number of people use this data recording method, an idea can be generated on where the variations lie, for example:

- torque wrench
- cylinder head thread machining
- spark plug thread rolling
- crush washer tolerance
- user error

Engine and vehicle numbers will help narrow down date ranges of any cylinder head nonconformities, if any.

 

Ha ha ha..........itchy hand strikes again.

My last calculation on post no # 18 made me decided to choose 1.2mm copper washer thickness....DIY method, sanding down 1.5mm one to 1.2mm ... LOL. Result is below.
https://mbworld.org/forums/e-class-w...ml#post8365208

EDITED, wrong thickness copper washer used.
WIll be back

===============

Now the correct ones. --- ALL PHOTOS ARE FROM Cylinder 1









DIY thinned down to 1.2mm copper washer

DIY thinned down to 1.2mm copper washer















DIY 1.2mm copper washer average thickness





I should have made some 1.3mm thick copper washer for not-so-bad cylinders and use 1.2mm one for the worst out of target cylinders.
I think at 23Nm this softer copper washer got squeezed down to 1.15mm. Which is good for sealing.

 

Cylinder 2 and 3











Tomorrow I will do cylinder 4, which is the WORST one.

 

Near zero degree Now I color black to be opposite of RED. So black to be as close as possible to 12 o'clock or zero degrees.

 

So , my spark plugs bad machining acurracy is Cylinder 4, 5 and 6. They suit very well 1.2mm thick copper washer. Cylinder 1, 2 , 3 and 4, best use 1.3mm ones.







Let see what will happen after 5,000KM or a year at least if not 18-24 months from now.
This entire 2022 till 4th Aug my car done like 1,000 KM only.

 

Hi everyone! After reading this post (and several others) I've went on to replace the spark plugs in my 2015 E400 (212.065) equipped with the 276.820 engine. My car is located in Brazil and using the Xentry I was able to determine that it is set from the factory with homogeneous type fuel injection and fuel trim set to "slightly enriched". I suspect MB sets the fuel trim to rich as a default for Brazil because our gasoline has 27% ethanol on its mixture mandated by local law (standard gas here has a RON of 92). I've purchased the replacement spark plugs from FCP Euro and got the Bosch 96347 - VA6SIP80 EVO plugs.

I've bought my car second hand but it has a full dealer maintenance history (same dealer). It has 41.000km and the plugs were never replaced according to the dealer (they timed-out but the previous owner declined to replace them). I've marked their position before removing and found that the ones in the left bank were close to the 45° windows but not quite there. On the right bank they were barely in the 90° window from the injectors. For what is worthy at least, I can contribute to the indexing recommendation from the 2014 bulletin being kind of bogus since not even the factory can make that happen.

Upon removal, I've found out that the original spark plugs in my car are made by NGK (SILZKFR8D7S). They were in a decent condition given their age and crappy local fuel. Some contamination by iron oxide is present and slight amount of carbon deposit on the side of the plugs that faces the injectors and intake valves ("cool side"). All and all, I believe they are running at a good temperature.





Now to my conundrum... the NGK spark plugs I've removed have a heat range of 8 and the Bosch plugs I bought have a heat range of 6. I know both manufacturer have a different way of measuring heat range but all cross-references charts I've found online, put the NGK heat range 8 compatible to Bosch heat range 4. I've also compared both plugs and the ones from Bosch have the central electrode more exposed, which if it was a plug of the same make and model, would indicate it was a hotter plug. Looking on Bosch website it lists this plug as equivalent to the OEM plug (A0041596903) in some countries (such as Germany) but not in other, which just added to my uncertainty. According to the people in FCP Euro, both plugs (Bosch and NGK) are compatible and applicable to my engine. Looking at pictures of the original plug in the internet (A0041596903) I've also found out that there are made by Bosch now and with the heat range of 6.



In short, I have no idea if it's safe or not to put these Bosch plugs on my engine. I know hotter plugs can damage the engine pretty easily but given both plugs are from different makers I have no conclusive information whether the ones from Bosch are hotter or not. Have anyone had any experience with this?

Thank you!