M157 owners beware! Spark Plug Indexing
Thread Starter
Member
Joined: Jan 2022
Posts: 182
Likes: 70
From: Jersey City
S63 Coupe
M157 owners beware! Spark Plug Indexing
I did the spark plug change today. Special thanks to @kenneyd for his amazing video
Mercedes really dropped the ball this time on spark plug manufacturing. My spark plug was never been changed before. Out of 8 OEM spark plugs, only 2 are barely at the edge of 45 degree, 4/8 are 90 degree, the rest of 2 are ridiculously 180 degree. Da*n it
( According to Mercedes, the spark plug needs to stay in a 90 degree range, 45 left and 45 right. Outside of that you're risking damaging the piston )
When I put in the new spark plugs, I also marked the position. All 8 are point to left 90 degree at 23nm. This means non of them will be correctly indexed if you play by the book.
My washers are all 1.5mm thick, I polished them to 1.1~1.2mm and finished the job.
I don't believe the dealer or any other indy will do the polish for you if you don't ask. Highly likely they will just play by the book, throw in the spark plug, torque to 23nm and call it a day.
I don't understand how could Mercedes blow this up. If you state in WIS for 23nm, and warn the users about indexing, then you should manufacture the right washer out of the box. Sanding them down is not the end of the world but I hate doing this kind of snake oil stuff on a 185k msrp car.
Guess I'm really pissed because my car has been driven for 46k with the risk of burning the pistons. And this mistake happened on a hand-built engine in the Affalterbach factory on day 1!
Take away: Do the spark plug yourself and properly index them. If you can't, pay special attention to the dealer or shop, ask them to do the indexing for you by sanding down the washer accordingly.
Mercedes really dropped the ball this time on spark plug manufacturing. My spark plug was never been changed before. Out of 8 OEM spark plugs, only 2 are barely at the edge of 45 degree, 4/8 are 90 degree, the rest of 2 are ridiculously 180 degree. Da*n it
( According to Mercedes, the spark plug needs to stay in a 90 degree range, 45 left and 45 right. Outside of that you're risking damaging the piston )
When I put in the new spark plugs, I also marked the position. All 8 are point to left 90 degree at 23nm. This means non of them will be correctly indexed if you play by the book.
My washers are all 1.5mm thick, I polished them to 1.1~1.2mm and finished the job.
I don't believe the dealer or any other indy will do the polish for you if you don't ask. Highly likely they will just play by the book, throw in the spark plug, torque to 23nm and call it a day.
I don't understand how could Mercedes blow this up. If you state in WIS for 23nm, and warn the users about indexing, then you should manufacture the right washer out of the box. Sanding them down is not the end of the world but I hate doing this kind of snake oil stuff on a 185k msrp car.
Guess I'm really pissed because my car has been driven for 46k with the risk of burning the pistons. And this mistake happened on a hand-built engine in the Affalterbach factory on day 1!
Take away: Do the spark plug yourself and properly index them. If you can't, pay special attention to the dealer or shop, ask them to do the indexing for you by sanding down the washer accordingly.
Last edited by zk2004mb; Jul 26, 2023 at 01:19 AM.
Thread Starter
Member
Joined: Jan 2022
Posts: 182
Likes: 70
From: Jersey City
S63 Coupe
I know this sounds silly but still want to verify with you guys. The injector is above the spark plug, is that right? Meaning we should keep the open space of spark plug upwards and the "pillar" downwards
Junior Member
Joined: Nov 2014
Posts: 73
Likes: 26
From: Las Vegas
'14 E63S, '00 E430, '07 C230
Never had to sand my washers down. The last time I did my spark plugs, I had my socket marked for the injector on top and all 8 of mine indexed within the window, some closer to TDC than others.
Super Member
Joined: Sep 2011
Posts: 878
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poop
Yes, you are correct. When you're standing at the wheel looking at the motor, the injector is on the top the spark plug is below it. The open part faces the injector, the strap faces down, away from it.
Senior Member
Joined: May 2023
Posts: 459
Likes: 164
From: Endless Mtns. PA
2014 E63 AMG wagon 1965 Austin-Healey 3000 1970 AMC AMX
I did the spark plug change today. Special thanks to @kenneyd for his amazing video https://www.youtube.com/watch?v=0JI9agbodWA&t=148s
Mercedes really dropped the ball this time on spark plug manufacturing. My spark plug was never been changed before. Out of 8 OEM spark plugs, only 2 are barely at the edge of 45 degree, 4/8 are 90 degree, the rest of 2 are ridiculously 180 degree. Da*n it
( According to Mercedes, the spark plug needs to stay in a 90 degree range, 45 left and 45 right. Outside of that you're risking damaging the piston )
When I put in the new spark plugs, I also marked the position. All 8 are point to left 90 degree at 23nm. This means non of them will be correctly indexed if you play by the book.
My washers are all 1.5mm thick, I polished them to 1.1~1.2mm and finished the job.
I don't believe the dealer or any other indy will do the polish for you if you don't ask. Highly likely they will just play by the book, throw in the spark plug, torque to 23nm and call it a day.
I don't understand how could Mercedes blow this up. If you state in WIS for 23nm, and warn the users about indexing, then you should manufacture the right washer out of the box. Sanding them down is not the end of the world but I hate doing this kind of snake oil stuff on a 185k msrp car.
Guess I'm really pissed because my car has been driven for 46k with the risk of burning the pistons. And this mistake happened on a hand-built engine in the Affalterbach factory on day 1!
Take away: Do the spark plug yourself and properly index them. If you can't, pay special attention to the dealer or shop, ask them to do the indexing for you by sanding down the washer accordingly.
Mercedes really dropped the ball this time on spark plug manufacturing. My spark plug was never been changed before. Out of 8 OEM spark plugs, only 2 are barely at the edge of 45 degree, 4/8 are 90 degree, the rest of 2 are ridiculously 180 degree. Da*n it
( According to Mercedes, the spark plug needs to stay in a 90 degree range, 45 left and 45 right. Outside of that you're risking damaging the piston )
When I put in the new spark plugs, I also marked the position. All 8 are point to left 90 degree at 23nm. This means non of them will be correctly indexed if you play by the book.
My washers are all 1.5mm thick, I polished them to 1.1~1.2mm and finished the job.
I don't believe the dealer or any other indy will do the polish for you if you don't ask. Highly likely they will just play by the book, throw in the spark plug, torque to 23nm and call it a day.
I don't understand how could Mercedes blow this up. If you state in WIS for 23nm, and warn the users about indexing, then you should manufacture the right washer out of the box. Sanding them down is not the end of the world but I hate doing this kind of snake oil stuff on a 185k msrp car.
Guess I'm really pissed because my car has been driven for 46k with the risk of burning the pistons. And this mistake happened on a hand-built engine in the Affalterbach factory on day 1!
Take away: Do the spark plug yourself and properly index them. If you can't, pay special attention to the dealer or shop, ask them to do the indexing for you by sanding down the washer accordingly.
Thread Starter
Member
Joined: Jan 2022
Posts: 182
Likes: 70
From: Jersey City
S63 Coupe
They hurt..... they hurt
How are your fingertips? I think I'm still missing most of my fingerprints LOL.
Yes, you are correct. When you're standing at the wheel looking at the motor, the injector is on the top the spark plug is below it. The open part faces the injector, the strap faces down, away from it.
Yes, you are correct. When you're standing at the wheel looking at the motor, the injector is on the top the spark plug is below it. The open part faces the injector, the strap faces down, away from it.
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E550 Coupe 2wd (2016)
Perhaps it's bs to get people to pay for the dealer to do the plugs, or at least get you to buy the plugs. Or maybe get out of warranty coverage. Fear is a powreful tool, especially when people are unwilling to test it. With all that's happening in the cyl I can't imagine it matters. Except maybe in stratified mode, which is light load only and no threat anyway.
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Joined: Jan 2022
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From: Jersey City
S63 Coupe
I started with 220, take off copper pretty quick, then 600 then 1000. The thread on my block are very consistent. I sanded all 8 to 1.12 or so. But you should put in spark plugs without sanding first to see how far off they are. Mine will all point to the left 90 degrees.
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From: Clearwater Beach, Florida
2016 Cls63s AMG
I started with 220, take off copper pretty quick, then 600 then 1000. The thread on my block are very consistent. I sanded all 8 to 1.12 or so. But you should put in spark plugs without sanding first to see how far off they are. Mine will all point to the left 90 degrees.
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From: Endless Mtns. PA
2014 E63 AMG wagon 1965 Austin-Healey 3000 1970 AMC AMX
curious to did your washers start to kinda slide off the plug after them being sanded down to that. I got one almost perfect facing up I went to pull it out for some more sanding and the washer was left down there. Scared me to death lol. I was able to pull it out with a pick easy.
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From: Endless Mtns. PA
2014 E63 AMG wagon 1965 Austin-Healey 3000 1970 AMC AMX
Ok, I sanded the side that seals to the base of the plug so it took about 25 turns of the washer to get it seated after sanding and there was no way jt was falling off.
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From: Endless Mtns. PA
2014 E63 AMG wagon 1965 Austin-Healey 3000 1970 AMC AMX
Carefully grab the edges with pliers and start rotating the washer off. Keep the washer parallel with the base of the plug and it will start to unscrew. Don't pinch too hard but keep it straight.
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From: Clearwater Beach, Florida
2016 Cls63s AMG
after almost loosing my finger tips ans nails i came up with this method and worked like a charm. 2 small dabs of glue and grab the glue stick and sand away. After done just snaps right off super essy
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'14 E63S, '00 E430, '07 C230
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E63 AMG
Dabs of glue on what? Glue stick afterwards where? Sand what off? Lol I’m lost. 😂
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From: par·a·dise
2012 E63 Wagon
Removed almost 2.5 mm of material from each washer before they pointed directly the injectors. Definitely going to save these washers for the next set of plugs.
None of my fingerprint readers worked for almost a week.
None of my fingerprint readers worked for almost a week.
Last edited by juststeve; Aug 5, 2023 at 09:39 PM.
