Dry Torque vs. Wet Torque
Dry Torque vs. Wet Torque
(OP)
Hello All,
I've been building engines for 20 years (motorcycle engines, mostly 2T race bikes). I've always known about the difference between wet and dry torque. But in all my service manuals there's a range given for torqueing fasteners, but never a mention of whether this is wet or dry.
Can anyone enlighten me as to what the Clymer, Chilton, and factory manuals expect?
Could it be that the torque range given by the manuals are meant to be deciphered as lower end of the range for wet and the high end of the range for dry torque?
Thanks! Todd
I've been building engines for 20 years (motorcycle engines, mostly 2T race bikes). I've always known about the difference between wet and dry torque. But in all my service manuals there's a range given for torqueing fasteners, but never a mention of whether this is wet or dry.
Can anyone enlighten me as to what the Clymer, Chilton, and factory manuals expect?
Could it be that the torque range given by the manuals are meant to be deciphered as lower end of the range for wet and the high end of the range for dry torque?
Thanks! Todd





RE: Dry Torque vs. Wet Torque
"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
RE: Dry Torque vs. Wet Torque
... because that's all they have at the factory.
I usually aim for the low end when using thread lubricant.
Mike Halloran
Pembroke Pines, FL, USA
RE: Dry Torque vs. Wet Torque
... because that's all they have at the factory.
Makes sense to me. Thanks for helping me clear that up!
RE: Dry Torque vs. Wet Torque
RE: Dry Torque vs. Wet Torque
RE: Dry Torque vs. Wet Torque
Loctite's literature states that their thread lock products act as a lubricant but I did a training course on bolted joints 2 years ago and the very knowledgeable instructor was adamant that this is not the case, based on my own experience (more feel than scientific based), I agree with him.
RE: Dry Torque vs. Wet Torque
They offer a fastener lube and make a few claims, among them consistent preload for a given torque from the very first torque cycle.
http://arp-bolts.com/i/t/PreloadGraph.gif
What I find most interesting about their spiel is -
** With almost any lube after several torque cycles the preload (and resulting bolt stress) approach the same value. ***
So, if, when I use something slippery to assemble fasteners I back off the torque a bit hoping to avoid overstressing the fastener, I ought to also lower the assembly torque if I'm re-assembling an engine for the 6th time with lightly oiled fasteners.
Actually, I sometimes will loosen and tighten fasteners a few times to create a smooth luxurious "feel"
RE: Dry Torque vs. Wet Torque
"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
RE: Dry Torque vs. Wet Torque
I have always understood if there is no mention of a lubricant then the torque figure is considered dry.
RE: Dry Torque vs. Wet Torque
I build Porsche 911 Engines on a regular basis and the factory manual tells you if the fastener should be lubricated.
I am not sure about aftermarket manual.
Thread lockers are interesting and Loctite do say that they act as a lubricant but provide no data of the effect on 'nut factor'.
If you read Permatex data sheets they tell you that the thread locker acts as a lube in terms of consistency but to torque to the standard dry torque figure.
What do you do about brand new fasteners? the surface roughness of the thread when first used can cause errors in preload.
All new fasteners need to be tightened a couple of times to burnish the threads and eliminate variability.
The modern trend of using lower measured torque and then tightening through a specified angle removes many of these issues and gives much more consistent preload results.
RE: Dry Torque vs. Wet Torque
je suis charlie
RE: Dry Torque vs. Wet Torque
"Formal education is a weapon, whose effect depends on who holds it in his hands and at whom it is aimed." ~ Joseph Stalin