Ugh, I think I may have put them too tight. Anyone know off the top of their heads please?

Adam

Sorry, I don't have my Bentley Manual handy. I always do it by feel. If you can wait until I get home from the office I may have an answer for you.

Sorry, I don't have my Bentley Manual handy. I always do it by feel. If you can wait until I get home from the office I may have an answer for you.

No problem. Im in my office to. I wont be working on it until later this evening. Thanks for the help.

Standard is actually hand tight and then another 90° (quarter turn).

Here you go!


5.2 Spark Plugs

Lightly lubricate the new spark plug threads with a little oil. Thread the plugs into the cylinder head by hand to prevent cross-threading. Torque the spark plugs.

Tightening Torque: 20 to 30 Nm (15 to 22 ft-lb)

For the record, I don't trust most torque wrenches to accurately measure such small values unless the instrument has been recently calibrated and the torque rating is at least 30% from both the maximum and minimum values the wrench is capable of measuring. Even then, I still prefer to do it by hand. They just need to be snug. A little twist of the wrist is all that is necessary.

5.2 Spark Plugs

Lightly lubricate the new spark plug threads with a little oil. Thread the plugs into the cylinder (http://forums.bimmerforums.com/forum/showthread.php?p=12529581#) by hand to prevent cross-threading. Torque the spark plugs.

Tightening Torque: 20 to 30 Nm (15 to 22 ft-lb)

I heavily disagree on using oil and I'm surprised to learn that such an advice is given in a reputable manual.
Oil can burn in the thread and almost "weld" in the spark plug. If lubrication is requested (I never do it) copper grease is the correct stuff to use.

Wolf, while I agree with you in theory about not oiling the threads on sparkplugs, it has been a common practice forever and most manuals and books prescribe it. There are a number of manufacturers who also want a light film on block studs when torqueing down an aluminum head (Ferrari, Alfa and others). In years gone by I have oiled plug threads in both cast iron and aluminum heads when the threads seemed a little "funny". I've never experienced any adverse effects from it. On the other hand, I was amazed at how much torque I was applying by just snugging them down with a 3/8" drive. I feel that the 20ft/lb while it seems low, actually provides enough room for heat expansion at operating temps and the plugs are quite tight at that point. I guess it's all in the "touch", Joe

Wolf, while I agree with you in theory about not oiling the threads on sparkplugs, it has been a common practice forever and most manuals and books prescribe it. There are a number of manufacturers who also want a light film on block studs when torqueing down an aluminum head (Ferrari, Alfa and others). In years gone by I have oiled plug threads in both cast iron and aluminum heads when the threads seemed a little "funny". I've never experienced any adverse effects from it. On the other hand, I was amazed at how much torque I was applying by just snugging them down with a 3/8" drive. I feel that the 20ft/lb while it seems low, actually provides enough room for heat expansion at operating temps and the plugs are quite tight at that point. I guess it's all in the "touch", Joe


I once had a problem with it on a motorcycle and finally I pulled the spark plug including the thread. Cast iron heads are certainly not that critical but with aluminium heads I'd definitely stay away from oil.

Wolf