Aftermarket Bosch Plugs vs. Plugs from MB dealer.

[The Critic]

Edit: The aftermarket Bosch plugs have ZR6SII3320 have printed on them. The Genuine MB plugs have ZR6SII3320R printed on them. Both plugs were Made in Germany. Obviously the MB plug (right) is used, but the electrode design looks very different to me. Bosch says it is the correct plug for the application.

Thoughts? The new plug was purchased from Worldpac.

 

[drtyler]

Probably an update since the MB plugs were manufactured.

I've heard some BMW and MB mechanics swear the BMW or MB branded Bosch plugs are different from the generic over-the-counter Bosch plug, but I've seen no evidence of it personally. Well your picture counts, I guess.

You should order a new Genuine MB plug and see which one it looks like.

 

[Wolf359]

It's been discussed in the Mercedes forums. Basically the MB plugs are different than the regular ones that Bosch sells. The MB plugs are indexed, properly, the regular Bosch plugs are not even though it's the same part number. Been like that for a while. Really one of the few times that it matters who you get them from. Of course buying the Bosch plugs from someone besides an MB dealer is much cheaper, but you'd have to index them yourself.

 

[Braapdaddy]

I believe my last set MB plugs were made by NGK

 

[The Critic]

http://www.porshaw.com/images/Bosch_SuperPlus_DesignationCodes.pdf

I guess the R at the end stands for burn-off resistor. Not sure how that affects the center electrode design?

 

[The Critic]

It's been discussed in the Mercedes forums. Basically the MB plugs are different than the regular ones that Bosch sells. The MB plugs are indexed, properly, the regular Bosch plugs are not even though it's the same part number. Been like that for a while. Really one of the few times that it matters who you get them from. Of course buying the Bosch plugs from someone besides an MB dealer is much cheaper, but you'd have to index them yourself.

Not true:

Spark Plug Indexing on ML 350 M276 engine

Been lots of discussion on the internet about the reality of spark plug indexing on the later Mercedes engines. Well, the original spark plugs on my 2015 ML 350 were definitely indexed, with the ground electrodes all pointing in the same direction. I marked the socket before removing them, and...

www.benzworld.org

 

[Trav]

Easy enough to verify the indexing.

 

[wpod]

I would use the Mercedes dealer plug for the simple reason pushing the point of a Mercedes buyer would want the best part for their best car.

 

[slacktide_bitog]

Maybe it's just the difference in wear?

The new one might look like the old one after some time and miles.

 

[measureman]

If it makes a spark why worry what it looks like.
A spark is a spark.

 

[Slow Car Sport Mode]

If it makes a spark why worry what it looks like.
A spark is a spark.

It can change how the whole car acts.

 

[measureman]

It can change how the whole car acts.

For a long time when I changed my own plugs I put Bosch Platinum plugs in many different makes of cars and they all ran just fine.
Spark is a spark.

 

[bobdoo]

A "spark is a spark" isn't quite true in modern cars. My CX-5 analyzes the resistance during spark, and uses that for tuning.

In addition, different center and side electrode sizes and shapes affects flame kernel growth. And deposit burn-off, too.

 

[Wolf359]

A "spark is a spark" isn't quite true in modern cars. My CX-5 analyzes the resistance during spark, and uses that for tuning.

In addition, different center and side electrode sizes and shapes affects flame kernel growth. And deposit burn-off, too.

Well there are also multispark systems out there too. I think Ford had waste fire systems where the plugs would also fire on the exhaust stroke for better emissions. Now Mercedes and other systems do up to 4-5 sparks per cycle for better combustion.

 

[Slow Car Sport Mode]

A "spark is a spark" isn't quite true in modern cars. My CX-5 analyzes the resistance during spark, and uses that for tuning.

In addition, different center and side electrode sizes and shapes affects flame kernel growth. And deposit burn-off, too.

Not to mention the gap.

Was going to ask if Mr. A Spark is a spark (of course of course) was referring to cheap copper plugs being the best but.. claim maybe does not hold water..

 

[nthach]

A "spark is a spark" isn't quite true in modern cars. My CX-5 analyzes the resistance during spark, and uses that for tuning.

In addition, different center and side electrode sizes and shapes affects flame kernel growth. And deposit burn-off, too.

Saab was doing that before Mazda did. They called it Trionic - it used the ionization current from when a spark plug is fired for detonation/misfire detection.

 

[The Critic]

Easy enough to verify the indexing.

The plugs are not very accessible.

(The plugs are on the “underside” of the cam cover, and at an angle.)

I suppose I could have marked the plug-to-socket orientation for both plugs, but the car works fine for now.

 

[OVERKILL]

The plugs are not very accessible.

View attachment 107047
View attachment 107046

(The plugs are on the “underside” of the cam cover, and angled.)

I suppose I could have marked the plug-to-socket orientation for both plugs, but the car works fine for now.

Sweet JESUS!

 

[ekrampitzjr]

Are SplitFire plugs available for the Mercedes-Benz? Might be worth a try.

 

[Astro14]

If it makes a spark why worry what it looks like.
A spark is a spark.

Indexing can change where the spark is directed inside the combustion chamber and make a difference in how the engine runs.

My Mercedes both use NGK plugs.

If the OP‘s car were mine, I would go with genuine MB in this case.

People who have run Bosch in their M275s have regretted it.