I read this on another forum:

"Fastener torque specs should be stated as either lubed or dry. In the case of head bolts torques they are (generally) spec'd as lubed so no adjustment is needed. If fasteners have a zinc (or better yet cadmium although now very unlikely) plating it will act to reduce thread friction too.....

....On the other hand, the manufacturers very likely have tested both lubed and non-lubed fasteners and spec'd their torques settings in such a way as to work for either. I used to work for a fastener manufacturer as an engineer and for some applications this stuff becomes very important."

eglaude, aren`t you going from one end of the spectrum to the other when you ask should you lube or lock?

On small(aluminum, magnesium) engines I lube fasteners, some with anti-siez, some with just a film of oil. I`d say to give you a staright answer, how has your experience been using anti-sieze? Have you had problems with your method?

Barbedwire, thanks for the feedback, but I don't think that there is that much difference in the two. In both cases the threads are lubricated and torque settings become different at that point.
I'm with you on the aluminum engines, I usually lube the bolts and anti-seize the plug or bolts subject to high heats. My experience with both have been good, however there have been some head bolt strips due to over torque. I'm not quite sure if it was due to the lube or just that the threads were stripped on the way out of a block that did not use a thread lubricant.
The thread locker I use on high vibration applications. Typical are on carb screw threads or on pump applications.
I even heard that putting a light film of anti-seize on the flywheel end of the crankshaft is not recommended. I must admit, I never had to use a puller or a big hammer to remove any of my flywheels! Just kidding with the big hammer, I know that some flywheels can be a bear to remove when rusted in.

eglaude I use anti seize and thread locker pretty much as you say you do. And absolutely never use any lube on the flywheel/crank. The tapered fit of the crank and flywheel when compressed by the retaining nut creates the friction which keeps the flywheel timed to the crank. The alignment key is just that, for alignment and not to keep the flywheel from spinning on the crank. Lube of any kind will cause shearing of the key.

Thanks nevada walrus for your advise on the flywheel. Let me ask you then, would you anti seize the flywheel nut?

I know this is a car engine, but when I rebuilt my 350 small block with aluminum heads, I used arp thread sealant on the head bolts since they went into the water passages, with arp moly lube around the heads of the bolts underneath the washers. I could have used oil under the bolt heads, but arp calculates their torque specs with their lube so I used it. I lubed up my intake and header bolts with oil per the instructions with the heads. I used the antisieze on the spark plugs. However, I used thread locker when I put on my flywheel and clutch bolts. I wouldn't use antisieze on flywheel bolts. Those are things that you don't want coming loose.

Thanks for sharing your good advice den69rs96. I'll be looking into the arp thread sealant. Sounds like a good product when dealing with applications that are subject to high heats like those on alum blocks. Something I really never thought to do, sealing threads. Not sure if this is unique to applications like yours or if it can be used in general. I like the fact they take it into account for torque settings. I would venture to say that a plain 30W oil on the threads is still a good alternative, for alum or cast blocks. Spark plugs are the ones that get you when they sieze on the block, the threads just tear right out without the antisieze. Locking the flywheel nut is the way to go too. I will heed the good advice there from all.
Thanks again, and keep the advice coming, this is some good stuff.
Eric

30w is better than nothing but it might be a wasted application. The anti-seize compounds are formulated for different temperature environments. I think nickel is used in the higher temp environs. Aluminum and copper are also used in some versions.

Teflon tape is another way to stop the reaction but of course you would not want to use that in a hot environment.

IMO the main problem fine dirt. fine sand particles fall into the threads. this IMO creates a abrasive reaction and gulls the threads. This is way I alway clean the spark plug area with carb cleaner and blow out the spark plug cavity before I remove the plugs (this also includes any assemble hardware). This not only keeps sand particles from working their way into the threads but prevent them from falling into the cylinders and scratching the bore on installation.

IMO as long as the threads are clean and undamaged, (some times this requires a tape or die on the bolts to clean them up or a new bolt) the torque will be good. If you do use lubricants too much can be worse that none at all. not only by corossion but a potentally hydralic affect in the threads if they are captured. JMO

Hi I have gathered a few information about lubrication of threads

Testing Conclusion:

-Threads lubricated with 10w-40 oil gave the most consistent results.

-Placing 10w-40 oil on threads does not change the bolt tension.

-Threads with anti-seize paste added to it has as much higher tension (Up to 71% increase) than with dry threads. That extra tension could conceivably strip out the threads. This could be the reason why spark plug installation specify that a 3/4 turn after seating rather than a torque value.

Daniyal is right - adding some lube on bolt threads DOES alter the torque and tension on the bolt\engine block threads. It makes the threads slide easier adding more stress on the threads. 150ft/lbs with lube is a lot tighter than without. Call the builder for specs on with\without lube\locktite\etc. For my short stint in aircraft repair, when there is no spcified torque there is the formula of many factors like class of bolt, type, material, etc, AND IF LUBED to properly calculate the proper torque. How tight before small engine blocks strip, you got me but don't go nuts lubing the bolt and cranking down on them.