Torque , to lube or not

[DblackmanC]

Hey something I can help with!!

Yes...Plugs should never be removed from a hot motor. Spark plug holes are drilled and threaded at room temperature. Therefore the thread pitch is set at room temp and plugs should only be installed or removed at room temp. As others have said the metals expand at different rates and the problem here is the Alu. will expand about 10 to 1 over steel. The problem is not the hole getting bigger but the thread pitch is changing more than the plug does. This is why some times you pull out some threads. If your plugs start getting hard to remove or install at room temp it is not the anti-seize but the carbon getting in the threads and on the plugs. Always use a lubed up thread chaser to clean out the hole and catch the paticles. your prolems will be gone. IMHO...always use anti-seize and always torque to the lowest spec.
Dan
PS...Do not use oil or grease on your threads. The temps. reached on the plug threads will turn them to very hard deposits and can mess up your threads coming out.

[DavePard]

Dissimilar metals are less likely to gall. Similar need lube absolutely.

[Jeffd]

Dissimilar metals are less likely to gall. Similar need lube absolutely.

http://www.engineersedge.com/galvanic_capatability.htm

[Admiral Akbar]

problem here is the Alu. will expand about 10 to 1 over steel.

So where did you get your info from?

                  (10-6 in/in deg F)

Aluminum    12.3

Steel           7.3


From
http://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

Max

[DavePard]

Jeff, That's a good point. Galvanic corrosion/oxidation. Dealt with that on aluminum truck frames where meets steel hardware/brackets. Spray on some dirty or even salt/potassium chlora...whatever water and time ... a real mess!

I've been fortunate to not have seen but galling  on spark plug threads. Plugs with rolled threads and quality (nickel) plating work better.

I've been using, as someone mentioned, either a copper anti-seize or one with nickel on just a couple of threads.

Have observed the lube drop out of anti-seize when used on exhaust headers and turbo's. That has to happen on sparkplugs too.

Best regards

[Dan89flstc]

2 types of antiseize -- aluminum and copper...yeah nickel also

Silver, Moly, Zinc, Graphite,

Fel Pro C200, C300,
PWA 36545...

Are there still only 2 types of Anti-Seize?

For spark plugs, just use Champion 2612 spark plug antiseize.

[Pilgrim]

Some people's problems are caused by trying to take the plugs out while the engine is hot.  That's inviting disaster unless you're working on an iron head.

Heck, That's one of the tricks I use to pull plugs that are stuck.. The coefficient of expansion is higher for aluminum then it is for steel..Plug will loosen up..  Max

That certainly makes sense, just as it does for trying to get any threaded fasteners loose.  My thoughts when I've seen threads pulled out of hot aluminum holes (not just plugs) is that the aluminum, softened by the heat, is easier to pull out when there is resistance from another source. 

Pilgrim

[Admiral Akbar]

My thoughts when I've seen threads pulled out of hot aluminum holes (not just plugs) is that the aluminum, softened by the heat, is easier to pull out when there is resistance from another source.

I think you might be mixing situations here.. Yeah sure, if a bolt is holding 2 aluminum pieces together so that there has some length of aluminium to travel before the bold/stud hits threads, you have a bolt/stud that has it's tension on the treads increased by the expansion of the aluminum. Also as you say heating certain types of aluminum and can make it softer.. You are more prone to galling. Need to understand the material you are dealing with and what you can get away with..

Max

[Eleft36]

Hey something I can help with!!

  PS...Do not use oil or grease on your threads. The temps. reached on the plug threads will turn them to very hard deposits and can mess up your threads coming out.

I found the never seize was hardening, using a drop or 2 of synthetic and have not had any problem.

Al

[rbabos]

Hey something I can help with!!

  PS...Do not use oil or grease on your threads. The temps. reached on the plug threads will turn them to very hard deposits and can mess up your threads coming out.

I found the never seize was hardening, using a drop or 2 of synthetic and have not had any problem.

Al

I found the same too. It seems to pack up in the threads and grab the plug when removing them, at least the copper stuff I used does.
Ron