BMW E46 Fanatics Forum banner

1 - 20 of 25 Posts

·
Registered
Joined
·
888 Posts
Discussion Starter #1 (Edited)
Many claim we should apply a 18 Lbf*ft torque with our E46 plugs

As a matter of fact, BMW says two things about this, as shown below (1st pic from left)
The information is extracted from BMW TIS (Troubleshooting system).
Those figures apply to all BMW engines/models.


BMW states we should be using two different torque depending of the thread lenght, thus depending on the engine too. For instance those with a short thread are meant for engines that have a large cylinder head. Not our case on E46.

So it means we have to use the one that uses the long thread, in essence according to BMW, the torque to be used in our case is 30 ± 3Nm, thus 22 Lbf*ft, with a tolerance between 19.9 Lbf*ft and 24 Lbf*ft.

On picture 2 (In the middle) you can see the plug on the far left is meant for large cylinder head, not our usual E46 plug. The one of the far right is the type we use on E46, notice the long thread here as opposed to the one on the far left, very short. The one on the left is also wider.

Finally the last picture (From left) shows you what/where the thread is, so we are clear on this.

Now I have taken into account that some people recommends to use Anti-Seize. As a matter of fact an anti-seize product has a torque multiplying effect. But is is not recommended by BMW to use Anti-Seize when installaling plugs. Porsche also do not recommend using Anti Seize, along Pelicanpart and many other online resources. See below for some additional explanations.

Autolite:
We do not recommend the use of any anti seize products for installing spark plugs. Anti seize compounds are typically composed of metallic, electrically conductive ingredients. If anti seize compounds come in contact with the core nose of the plugs, it can lead to a misfire condition.
Anti seize compounds can also have a torque multiplying effect when installing plugs. This can lead to thread distortion and thread galling
resulting in cylinder head damage. Autolite spark plugs are nickel plated to resist the effects of corrosion and seizing. However, plug seizure is aggravated further when steel plugs are installed into aluminum cylinder
heads for a long period of time.


AC/Delco:
Do not use any type of anti-seize compound on spark plug threads. Doing this will decrease the amount of friction between the threads. The result of the lowered friction is that when the spark plug is torqued to the proper specification, the spark plug is turned too far into the cylinder head. This increases the likelihood of pulling or stripping the threads in the cylinder head. Over-tightening of a spark plug can cause stretching of the spark plug shell and could allow blowby to pass through the gasket seal between the shell and insulator. Over-tightening also results in extremely difficult removal.


Now guys this is based on personal research, I am not a mechanic, so if I am wrong anywhere, please correct me with constructive remarks.

If you decide to use Anti-Seize anyway, you should be reducing the torque value by 20%, therefore even the 18 Lbf*ft is not correct, well unless you decide the smallest possible BMW torque recommendation, 19.9

HTH

EDIT: Additional information provided 11-02-2009

Importance of the torque


If a plug is not fully seated on the cylinder head, it will not transfer heat effectively and may leak combustion gases. Poor heat transfer can raise cylinder temperatures dramatically, causing detonation and plug or engine damage. Over-tightened plugs can also cause damage to the plug and to the engine head threads. Damage to the plug's seals or the insulator can slow heat transfer and cause pre-ignition and detonation. Making sure to use the proper torque wrench will help to avoid these types of problems. Always install spark plugs in a cool engine, as hot metal expands and may limit the ability to tighten. Additionally, it helps to clean the threads in the head and on the plug.

Difference between Platinum and Copper plugs

The Platinum spark plug is the same as the Copper but the central electrode has a platinum tip, which improves corrosion and erosion resistance and provides longer life and smoother performance.
Many people do claim the Platinum type spark plug has a lower life expectancy than a classic spark plug with copper. Although the platinum one offers better performances, it is to be noted that they accumulate dirt more quickly than classic plugs. Therefore, a simple cleaning (Dry wipe/brush) will restore their full potential. Simply remove the plugs and give them a good wipe.
 

Attachments

·
Registered
Joined
·
480 Posts
Good Info, I would also like more input on this. This morning I put in new plugs I used anti-seize and torqued them down to 18 lb ft, should I redue the plugs with out ainti-seize or loosen the plugs to less torque ?
 

·
Registered
Joined
·
7,493 Posts
ive never used anything on any plug ive ever put in anything
 

·
Registered
Joined
·
888 Posts
Discussion Starter #5
Good Info, I would also like more input on this. This morning I put in new plugs I used anti-seize and torqued them down to 18 lb ft, should I redue the plugs with out ainti-seize or loosen the plugs to less torque ?
Yes you sould remove them and do it again. Clean them up and tighten them at 22 Lbf*ft.
 

·
Registered
Joined
·
888 Posts
Discussion Starter #9
Additional information provided, based on extra research since

Please see the original post for the update.

Cheers
 

·
Registered
Joined
·
651 Posts
Now I have taken into account that some people recommends to use Anti-Seize. As a matter of fact an anti-seize product has a torque multiplying effect. But is is not recommended by BMW to use Anti-Seize when installaling plugs. Porsche also do not recommend using Anti Seize, along Pelicanpart and many other online resources. See below for some additional explanations.
I totally disagree with the post. If you are going to change the plugs after 30k. Okay that's fine, don't use anti-seize. Your BMW plugs are going to be on there for 60k, 80k, 100k miles. You ever snap one and have the electrode drop into the cylinder.
If you decide to use Anti-Seize anyway, you should be reducing the torque value by 20%, therefore even the 18 Lbf*ft is not correct, well unless you decide the smallest possible BMW torque recommendation, 19.9
Torque setting?? Change torque reading 20%, I don't believe that number, that huge. Engine builders use Threadlockers on like flywheel bolts, they don't change the torque. If it's 10%(still a lot) it's still within BMW's torque range of 19.9 to 24. There's also a crush washer(seat) on the spark plug helps too.
So it means we have to use the one that uses the long thread, in essence according to BMW, the torque to be used in our case is 30 ± 3Nm, thus 22 Lbf*ft, with a tolerance between 19.9 Lbf*ft and 24 Lbf*ft.
AC/Delco:
Do not use any type of anti-seize compound on spark plug threads. Doing this will decrease the amount of friction between the threads. The result of the lowered friction is that when the spark plug is torqued to the proper specification, the spark plug is turned too far into the cylinder head. This increases the likelihood of pulling or stripping the threads in the cylinder head. Over-tightening of a spark plug can cause stretching of the spark plug shell and could allow blowby to pass through the gasket seal between the shell and insulator. Over-tightening also results in extremely difficult removal.
Blowby is extreme, you'll have to torque it to like 40lb to crack it.

Difference between Platinum and Copper plugs

The Platinum spark plug is the same as the Copper but the central electrode has a platinum tip, which improves corrosion and erosion resistance and provides longer life and smoother performance.
Many people do claim the Platinum type spark plug has a lower life expectancy than a classic spark plug with copper. Although the platinum one offers better performances, it is to be noted that they accumulate dirt more quickly than classic plugs. Therefore, a simple cleaning (Dry wipe/brush) will restore their full potential. Simply remove the plugs and give them a good wipe.
Platinum last longer, that's why our can go 100k. They last longer because the platinum tip run super hot and can burn off carbon build up on the electrode better the copper core. Copper core are better performers, because they are better conductors. A wipe/brush might knock out the platinum tip. Restoring should be more like re-gapping plugs if to can.
 

·
May the farts be with you, always
Joined
·
6,735 Posts
anti-seize is always applied..you'll get bad ticking with improper torque specs.
 

·
Registered
Joined
·
888 Posts
Discussion Starter #15
anti-seize is always applied..you'll get bad ticking with improper torque specs.
Says who?
BMW does not recommended as many other sources as pointed out in the explanations.

I am happy to change anything in the post to reflect the reality of things, and I stand corrected guys no problem, just for the sake of the truth, point me out to some sources.
 

·
Registered
Joined
·
36 Posts
Porsche also says no to Anti-Sieze too.
One thing I wanted to ask is, since there is a crush washer, I never reuse the plugs once i take them out. I don't bother "inspecting them". If I take them out I just replace them. You're not suppose to reuse the crush washer anywhere else like your engine oil plug or diff plug. why reuse spark plugs? I think once they are installed they shouldn't be re-installed, simply because of the crush washer.
 

·
Registered
Joined
·
3,344 Posts
how do i properly torque spark plugs and other things that need torquing? (flame suit on.... serious question though)
 

·
Registered
Joined
·
532 Posts
+1 Don't remove, clean and put back the same plug.

Some schools say to wrench it to through the crush washer and when hitting "bottom", turn 1/4 more..


Porsche also says no to Anti-Sieze too.
One thing I wanted to ask is, since there is a crush washer, I never reuse the plugs once i take them out. I don't bother "inspecting them". If I take them out I just replace them. You're not suppose to reuse the crush washer anywhere else like your engine oil plug or diff plug. why reuse spark plugs? I think once they are installed they shouldn't be re-installed, simply because of the crush washer.
 
1 - 20 of 25 Posts
Top