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Engine Specific Info and Questions => IDI Engine => Topic started by: 92EcoDiesel Jetta on June 23, 2009, 11:30:21 am
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I remember when I bought new tires at Costco, the tech wiped off all the anti-seize that I had put on the lug nuts before torqueing them to spec. When asked, they said the anti-seize acts as a lubricant on the threads so that the correct torque value is not achieved, that torque specs are for dry threads. Do you agree with that?
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Yes, that is absolutely true. When torquing larger bolts (3/4" or more) at work we always used copper anti-seize on the threads. The torque would often be reduced by 100 ft. lbs or more. The torque values can also change between lubes. For instance, anti seize will reduce the friction more than say motor oil.
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Yes, that is absolutely true. When torquing larger bolts (3/4" or more) at work we always used copper anti-seize on the threads. The torque would often be reduced by 100 ft. lbs or more. The torque values can also change between lubes. For instance, anti seize will reduce the friction more than say motor oil.
Wow i had no idea. Thanks 2X
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Yes, that is absolutely true. When torquing larger bolts (3/4" or more) at work we always used copper anti-seize on the threads. The torque would often be reduced by 100 ft. lbs or more. The torque values can also change between lubes. For instance, anti seize will reduce the friction more than say motor oil.
Ditto !! In fact, some head bolts torque are spec'd with the use of anti-seize !!
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How's the VW Bently values spec'ed? With or without anti-seize?
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anti seize is great stuff. i use it on everything! especially lug bolts/nuts. makes it that much easier to take off, and if you tighten them to the regular spec, they have that much extra clamping force, without the need to over tighten them. without lube, a portion of the tightening goes to overcoming the friction between the metal surfaces. so that Costco guy is incorrect, as you will not only achieve the minimum spec, but even more of a safety margin. i tried explaining that to my brother who insists on over tightening them without it... ::) ;D oh well his problem when he's at the side of the road with a flat tire :P
the bentley values spec are without anti-seize, but rather with regular 10w30 motor oil (where it calls for lube).
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My concern is over-torqueing the bolt. Is there a formula for torque reduction when using anti seize? I wonder if it's on the anti- seize container?
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What lube, if any, is especially important if you are dealing with torque to yield (stretch) bolts.
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NEVER use anti-seize on lugs.
And this is coming stright from he nut and bolt guy at GM's tech center.
Not only will it change torque values, It'll collect debris when you have them off - sometimes enough to damage threads. After all, how tight is everyone going with these? 100 ft/lbs. is normal spec, and isnt hard to undo at all.
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On the threads it isn't as critical as the mating surfaces. If you put a lube on the face of a washer or nut it will dramatically affect the torque. On the threads it will have an effect but not near as profound. You can stretch the living snot out of a stud if you lube the threads and mating surfaces. I use a little on the lugs not the mating surfaces and haven't noticed but a 5 ft/lb difference, and rust is always more of a problem than overtorque for me. I don't recommend it because all the manufacturers don't. I suspect that is probably so the people that don't have antiseeze torque a lug to 80 ft/lbs and the wheel comes off it is a manufacturers' fault for not telling the difference.
Also, any head bolt/stud that goes into a water jacket I will put anti seeze on NO MATTER WHAT the manufacturer says. The 1.6 VW has all blind holes so nothing to worry water wise there.
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I've never used an anti-seize compound. I would think it might make critical torque specs more difficult to achieve and would not use it on head bolts or wheel studs/nuts. I believe that on some surfaces such as brake calipers where there is movement on the sliding surfaces at the calipers then it makes perfect sense because you want it to move without binding up. Apart from that and door and trunk locks and hinges etc. I am not so sure.
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I've never used an anti-seize compound. I would think it might make critical torque specs more difficult to achieve and would not use it on head bolts or wheel studs/nuts. I believe that on some surfaces such as brake calipers where there is movement on the sliding surfaces at the calipers then it makes perfect sense because you want it to move without binding up. Apart from that and door and trunk locks and hinges etc. I am not so sure.
a good high temp anti seize might be good for brake caliper sliders, but i'd just stick with the good ol brake lube.
there should be no reason to not use anti seize on lug nuts. the dirt theory is fallacious to me as the anti seize is used in the drilling of oil wells, so that they can easily install/remove the sections. and they use mud to lubricate it all. if anything, the anti seize would allow the dirt to be easily pushed through if you lube it up real good.
a properly maintained car will probably be okay without the anti seize, but if you rarely take your tires off, its a good idea. i just add it because if i was ever caught at the side of the road, i would want to use as little effort as possible to change the tire, especially if its raining or snowing :o and its my opinion that the lug nuts/bolts need to be replaced after a while due to the frictional damage... or over torquing.
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What lube, if any, is especially important if you are dealing with torque to yield (stretch) bolts.
Not to be smart or anything but as far as lube for stretch bolts as far as I'm concerned just about anything on them that will help them slide into the trash can a little easier would work fine. I'll definately never use another one on a VW diesel, they're too much of a pain in the ass. ;)
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Its not as simple as just lubed or unlubed. Different lubes have a different torque (oil -25%, moly based -50%!). Then factor in if the bolt is plated & how. Zinc or cad plated bolts have different dry torque values.
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What lube, if any, is especially important if you are dealing with torque to yield (stretch) bolts.
Not to be smart or anything but as far as lube for stretch bolts as far as I'm concerned just about anything on them that will help them slide into the trash can a little easier would work fine. I'll definately never use another one on a VW diesel, they're too much of a pain in the ass. ;)
Hear Hear.
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and its my opinion that the lug nuts/bolts need to be replaced after a while due to the frictional damage... or over torquing.
OR from tire shop kids buzzing the life out of the lugs with an impact gun.
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and its my opinion that the lug nuts/bolts need to be replaced after a while due to the frictional damage... or over torquing.
OR from tire shop kids buzzing the life out of the lugs with an impact gun.
precisely! i actually think that they are trained to do this, just to make sure that wheels don't fall off and cause lawsuits. however, when they start buzzing the life out of the lugs with nice cold alloy rims.... ::) the alloy's don't play fair, and damage usually ensues.
Its not as simple as just lubed or unlubed. Different lubes have a different torque (oil -25%, moly based -50%!). Then factor in if the bolt is plated & how. Zinc or cad plated bolts have different dry torque values.
good point on the coated bolts. raceware has some special coating that significantly reduces the amount of torque required to achieve the proper clamping force, but i'll be damned if they are suitable for MLS gaskets as they tend to not 'crush' them. mine busted at around 90-100 ft/lbs and the gasket was still not crushed.
as for what VW says to use for lubing its stretch hardware, just regular 10w30 engine oil - NOT SYNTHETIC
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There are many misconceptions relating to torque, clamping force, friction and lubricating hardware. When I attended a torque training course, they told us that when you apply rotary force to a fastener with no lubrication, roughly 50% of the force is used to overcome friction under the bolt head, 40% will overcome friction on the threads, and only about 10% actually is utilized to stretch the fastener and results in clamping force. When you look at those numbers, you can quickly see that if you reduced friction by 10%, you double the torque available to create clamping force. This is why torque recommendation calculations always utilize the coefficient of friction. Any lubricant, plating, or liquid threadlocker affects the coefficient of friction. So yes, any lubricant will reduce the torque required to achieve a specified clamping force for a fastener. If the torque recommendation was made based on a dry fastener and was done close to the plastic limit of the fastener, just a little lubrication can result in a failed fastener. Note that the coefficient of friction is different for various lubricants. Plating is also functions as a lubricant. We specify a 20% reduction in torque values when going from using oil as a lubricant to using neverseize.
Living in Ontario, I would never consider putting wheel nuts or bolts on without using neverseize, especially during the winter season.