Spark Plug change ...

Oct 1, 2019 | 12:38 AM

C3504matic

Thread Starter

Senior Member

Joined: Oct 2013

Posts: 418

Likes: 90

From: Edmonton AB

2015 C63S ,DME Tune, KW Has ,Kmac Bushings,BC Forged wheels,Gt Rotors,Porterfield R4S,Modal Intake

Spark Plug change ...

Did a google search and can't find anything on a "how to" ...same with this forum ...anyone have any links ? Also ...gap .025 ?

Oct 1, 2019 | 04:52 PM

LessIsMore

Senior Member

Joined: Jun 2019

Posts: 453

Likes: 91

From: DFW, Texas

2017 AMG C63

+1 interested as well in a DIY.

Gap of .022" is recc for tuned cars. Wont hurt on mild/normal tune, but Id strongly suggest 0.022" for cars with dp/high boost/etc.

Oct 1, 2019 | 06:21 PM

ezatnova

Super Member

Joined: Dec 2011

Posts: 557

Likes: 71

2016 C63S

I’m doing my plugs on Saturday and then starting fresh with a Renntech tune. I’ll try and post some pointers assuming I can do it lol

also FWIW, talking to several of the best tuners, including Renntech, their consensus is that there is absolutely no need to change from OEM gap on the plugs. Renntech has had their R3 C63s running well over 700hp and only ever had stock gap plugs in it.

Oct 2, 2019 | 11:27 AM

raudiace4

MBWorld Fanatic!

Joined: Jun 2014

Posts: 1,589

Likes: 683

From: IL

19 E63s, 23 M3 compX, B9 SQ5

I just changed my stock plugs at 19K miles.. Replaced with stock equivalent Bosch iridium plugs, they are pre gapped so don't change that. DIY is pretty simple for passenger side, driver side requires removing fuel line to get to the plugs. Have rags ready to soak up spilled fuel LOL.

Oct 2, 2019 | 02:37 PM

nobbyv

Senior Member

Joined: Mar 2016

Posts: 497

Likes: 55

From: The NH

2016 Cardinal Red AMG C63 S

Quote:

Originally Posted by raudiace4

I just changed my stock plugs at 19K miles..

Can I ask why? I get if you go tuned you may want a different plug, but you swapped in the stock plugs at 19k that I believe MB says will go 100k...

Oct 2, 2019 | 03:06 PM

ezatnova

Super Member

Joined: Dec 2011

Posts: 557

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2016 C63S

Quote:

Originally Posted by nobbyv

Can I ask why? I get if you go tuned you may want a different plug, but you swapped in the stock plugs at 19k that I believe MB says will go 100k...

not speaking for him, but in my case I’m doing mine at 24k because my JB4 misfired 7 and 8 throwing a CEL, and occasionally “misses” (non CEL) when cruising at light throttle. Is this just the JB4 and my plugs are perfectly fine? Perhaps. After all, the car runs perfectly on map 0 at all times. However, for piece of mind while I go a new route with the car, it’s $140 and an afternoon spent with the car to ensure that the plugs haven’t been fouled or anything.

Now, if the JB4 caused extra stress on the coils due to the plugs struggling, then that may be a separate issue, but hopefully that isn’t the case.

FWIW, another reputable tuner mentioned to me that, while stock gap is perfectly good to use, a tuned W205 should have plus replaced every 15-20k. That’s just one data source though.

Oct 3, 2019 | 11:39 AM

raudiace4

MBWorld Fanatic!

Joined: Jun 2014

Posts: 1,589

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From: IL

19 E63s, 23 M3 compX, B9 SQ5

Quote:

Originally Posted by nobbyv

Can I ask why? I get if you go tuned you may want a different plug, but you swapped in the stock plugs at 19k that I believe MB says will go 100k...

Occasional misfires at idle. Take out your plugs and look at them. Stock you can get away with it, tuned stage 2+ I'll do mine every 20K miles and IDGAF what MB says.