Spark Plugs Binding on Removal

That's been a often asked question and it's been discussed in quite a bit of detail here.

I was forever a proponent of following the spark plug manufacturer's recommendations for not using anti-seize up until I changed out the plugs in my old ECHO this last time. On all my other old cars, I've never had one issue with not using it even after 100,000 miles or more. But this last time they were stuck much like you described and I was afraid I was going to strip the threads in the head. That didn't happen but when the new NGK plugs went back in I used a dab of nickel anti-seize on the threads. If you use the torque angle method of installation that's on the box then it doesn't matter if the threads are lubricated or not.

But like I said, with all the other plug changes on my cars (some four times in 20 years) never a problem until this time.
Please don’t do this on DI MB engines that require plug indexing.
 
Why would I? And how would using a target torque value be different, wouldn't you want to know the final angle?
An uninformed individual may read your post and view the advice to be universal for spark plugs. It is not.

The MB ones do not use crush washers, they use a harder copper washer that permits indexing when the plug is torqued to the specified value.

 
Please don’t do this on DI MB engines that require plug indexing.
I don't know why they did this. Do you know why?
When I changed the Malibu plugs (2.0 LTG DI), I went with stock AC Delcos, a dab of anti-seize and no indexing. I verified that it was not required.
 
The pdf has the reason. OE parts must be used and great care installing them.

Why? – Aftermarket and or “OEM” plugs are not manufactured to the precise specifications as the “factory original equipment” are.


To avoid piston damage the ground tab’s opening (of the plug) has to be facing directly at the injector nozzle (indexing) after torquing plug to factory specs.


There are technical bulletins published showing melted holes in the pistons and stating not their fault – should be using their parts!

mb di.jpg
 
An uninformed individual may read your post and view the advice to be universal for spark plugs. It is not.
Well okay, but your warning should apply to everyone in this thread then since regardless of the method of installation unless you had those special washers and special installation instructions nobody would index the plugs. In the context of this discussion whether you use a torque wrench to torque the plugs or you use the torque angle for tightening, neither one is going to somehow magically orient the plug unless that's your intent.
 
Well okay, but your warning should apply to everyone in this thread then since regardless of the method of installation unless you had those special washers and special installation instructions nobody would index the plugs. In the context of this discussion whether you use a torque wrench to torque the plugs or you use the torque angle for tightening, neither one is going to somehow magically orient the plug unless that's your intent.
Are you suggesting that it is not necessary to consult the factory service instructions before attempting a vehicle repair?
 
Are you suggesting that it is not necessary to consult the factory service instructions before attempting a vehicle repair?
Has someone taken over your account? You're not making much sense in the two small accusations you've made today.

You're barking up the wrong tree here. I've forever advocated that a person working on any automobile should have the FSM and I have them for all my vehicles including my new Tiguan. I've bought them since my first car in 1979. I won't even work on friend's cars without them.
 
So despite 'atikovi' apparently misreading my first post in this thread, I had a PM asking how I could've changed so many plugs, and why I didn't use anti-seize. I DO use anti-seize, and I stated why.

I changed plugs as a consumer car mechanic back in the day. Lots of spark plugs in my own bikes and cars over the years, some for family and friends. But by far the most has been in my professional racing hobby.

A typical race weekend where we make it to the final round, would mean 128 spark plugs used (144 at 'The Big Go'). multiply that potential number by the full tour, times 18+ years, and you're talking A LOT of spark plugs.
 
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Sure, on some aluminum heads like air cooled ones.

 
The pdf has the reason. OE parts must be used and great care installing them.



View attachment 53318
I used OEM on the Malibu, 2.0 LTG, but appears there is no procedure for those to be indexed. I think my main question was why would Mercedes design it like that? Seems as if could be messed up easily by anyone not really paying attention.
 
I used OEM on the Malibu, 2.0 LTG, but appears there is no procedure for those to be indexed. I think my main question was why would Mercedes design it like that? Seems as if could be messed up easily by anyone not really paying attention.
It has something to do with the direction of the flame during combustion. If it is in the wrong direction, it may cause damage.
 
Just wanted to update this thread. Looks like it sparked quite the discussion (pun intended).

I ended up getting all of the plugs out successfully! It only took me about 5 hours, lol.

I used a healthy shot of PB blaster down each of the plug holes and had to crank my torque wrench down to about 60lb/ft and used that to rock the plugs back and forth for what seemed like forever. I started out using my 8" ratchet, but I could hardly move them with such a short handle.

I used a small amount of the permatex anti seize others posted above before installing the new plugs. The back and forth with the PB blaster must have cleaned the threads out a little too, as I was able to thread the new plugs in by hand all the way down the seat before tightening the rest of the way.

I did my best to soak up any PB blaster with a shop rag before removing each loosened plug, and again after the plugs were removed, but I still got quite a smoke show on startup from the PB that had made it into the combustion chamber!

I was debating farming this job out because I didn't feel comfortable with it after trying to remove that first plug, but now I feel better knowing it was done right and that the threads weren't messed up by an impatient mechanic who just wanted them out of there quickly.

Thanks again to everyone who contributed. You guys gave me the confidence to tackle this job and see it through.
 
The pdf has the reason. OE parts must be used and great care installing them.



View attachment 53318
I wonder if the index of the spark plug in that DI engine affects LSPI? Wonder if thats the case in any other DI engine? Is that MB engine a turbo?

Is that plug indexed so that the open kernal is on the higher side of the head , away from the piston?
 
You used a torque wrench to remove plugs?
Yes. It was the only wrench I had with a long enough handle to give the leverage I needed. It was an 80lb/ft wrench and I set it to about 60lb//ft. This was more than was needed so the wrench wasn't "clicking" and was working pretty much like a standard 1/2" ratchet with a long handle.
 
I wonder if the index of the spark plug in that DI engine affects LSPI? Wonder if thats the case in any other DI engine? Is that MB engine a turbo?

Is that plug indexed so that the open kernal is on the higher side of the head , away from the piston?

The M276 is naturally aspirated, lots of high tech in this engine. Piezo injectors and ignition that fires multiple times per stroke.
This may help answer your question. The heat generated by this multiple firing is centered on the thickest part of the piston by indexing instead of overheating the thinner part over the ring lands.

 
Well done! I'm glad you got the plugs out and cleaned up the threads.
Do yourself a favor: go buy a few tools.
Using a torque wrench as a breaker bar makes BITOG cringe!
 
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