Torque: to lube or not lube

[Onder]

Read through the 'Torque: lube or no lube' thread. By the end it seemed to me nobody has The Answer.
It is time for me to torque down a head and I want to know "If I use thread lube, do I reduce torque setting
and if so by how much?"
Using ARP paste in my case so I asked ARP. Got back the cryptic answer which sort of was yes but use what
the vendor of the hardware recommends. So basically they kicked the can down the road and here I am
with torque wrench at the ready and thumb up me arse.
SO WOT IS THE CORRECT SETTING?

 

[Fast Eddie]

I too am aware of the theory and do not offer any robust theoretical counter.

But, personally, I have always used lube and standard torque settings and have never had an issue. In fact, on my Commando head I go a couple of lbs beyond at first build to help with the crushing / settling.

A caveat would be if you're talking about existing known weak threads, but I think you have inserts in those right?

 

[Onder]

No thread issues. No inserts on this application. But if you run down a lubed bolt v a unlubed blot you can turn it a lot further using the same wrench setting. So back off 10 percent? 20 percent? With standard rods you can measure bolt stretch. But then if you use billet rods you cannot do that and cannot, obviously, do it with head bolts/nuts.

 

[Fast Eddie]

No thread issues. No inserts on this application. But if you run down a lubed bolt v a unlubed blot you can turn it a lot further using the same wrench setting. So back off 10 percent? 20 percent? With standard rods you can measure bolt stretch. But then if you use billet rods you cannot do that and cannot, obviously, do it with head bolts/nuts.

No thread issues AND no inserts?

The 3 studs into the head are a known weakness. My point was that with threads like this, if you lube them and use standard torque settings, maybe they’d be close to the edge of overloading the threads.


But back to the more general topic…

”So back off 10 percent? 20 percent?“ EXACTLY … which theory to follow?

Whenever I’ve tried settings at 10 or 20% less they simply feel way too loose for my liking !

IMHO, there are more failures from under tight fasteners than (slightly) over tight. Hence, my own approach is to use standard settings with lube IN THE KNOWLEDGE that the theory says I am actually over torquing.

But, as I’ve argued before, I have doubts about the ‘dry vs lubed’ argument for two reasons:

1. What does ‘lube’ mean? There are countless lubes available, all of which will have different lubricity properties.

2. What does ‘dry‘ mean. No really, unless you have thoroughly cleaned and dried both male and female threads scrupulously with alcohol or similar, they WILL have some residual oil / grease on them, even if it’s cutting fluid from the machining process, or corrosion protection, etc. So, I would argue that seeing as 99.9% of us do not clean threads like this all of the time, then 99.9% of us are not fitting them dry even when we do not deliberately use lube!

Theres a third reason too, especially when dealing with old bikes and pattern parts etc, we are beholden to pattern part manufactures tolerance's. Threads that are not perfect will have different friction, especially when dry. I think it’s a definite risk that the clamping forces could be inadequate when assembling dry as torque could be consumed by overly ‘tightly cut’ threads.

So, in summary on a machines as crude was what we’re dealing with, using lube (to prevent seizing, galling, etc) and using standard factory torque settings has proven to be perfectly trouble free FOR ME.

 

[Onder]

I remember JIm Comstock saying he regularly added a few pounds...
But I DO know those three little studs are about maxed out at normal loads. Suspect NEW head can take it but our oldies not so much. After all I pulled those three out with no trouble on my Fullauto.
Almost always go with a solid head gasket but this time using a composite so under torque more of a worry.
"You puts yer money down and takes yer chances"

 

[concours]

Read through the 'Torque: lube or no lube' thread. By the end it seemed to me nobody has The Answer.
It is time for me to torque down a head and I want to know "If I use thread lube, do I reduce torque setting
and if so by how much?"
Using ARP paste in my case so I asked ARP. Got back the cryptic answer which sort of was yes but use what
the vendor of the hardware recommends. So basically they kicked the can down the road and here I am
with torque wrench at the ready and thumb up me arse.
SO WOT IS THE CORRECT SETTING?

I INCREASED the torque on my cylinder head, per the Norton factory published service bulletin.

The threads are lightly oiled, to prevent galling. INDUSTRY STANDARD.

Tightening dry threads (as in washed clean with brake cleaner) is: A) damaging to threads
B) inaccurate torque

Most laymen have oiled threads, quite by happy accident, the residual machining fluid, or the packing oil. They skate by blissfully unaware.

Anti-sieze & moly are used on assemblies with VERY HIGH torque values. (NeoLube Flange bolts on Reactor Circulator Pumps comes to mind)

It is clearly covered on page one of every service manual.
"It is assumed you already know some stuff."

Lather, rinse, repeat.


JMWO

 

[kommando]

Unless you know the conditions the factory used then the torque figures are mute anyway. Even if you do know and add a lube, which lube and what affect does that lube have. Unless you have access to both ends of the fastener so you can measure stretch its all guess work. You are looking to stretch the bolt within its elastic range and not go into the plastic range, so you need to know the material the bolt is made from too.

Bolt Nut Recommened Torque Table for SAE Grades

The following suggested tightening torques provide an excellent starting point for determining torque requirements.

www.engineersedge.com

 

[concours]

Unless you know the conditions the factory used then the torque figures are mute anyway. Even if you do know and add a lube, which lube and what affect does that lube have. Unless you have access to both ends of the fastener so you can measure stretch its all guess work. You are looking to stretch the bolt within its elastic range and not go into the plastic range, so you need to know the material the bolt is made from too.

Bolt Nut Recommened Torque Table for SAE Grades

The following suggested tightening torques provide an excellent starting point for determining torque requirements.

www.engineersedge.com

".....if you are designing, engineering or writing the technical manual"

Regarding the Cdo cylinder head, We can accept this part wasdone 55+ years ago.

 

[Onder]

And of course we can add "are you going into steel or alloy"...
I guess Ill comfort myself with "even torque is more important than how much torque"

 

[concours]

And of course we can add "are you going into steel or alloy"...
I guess Ill comfort myself with "even torque is more important than how much torque"

It is abundantly clear, that you seek a dialogue, rather than an answer to a basic mechanical question.
Good luck with your quest.

 

[Onder]

Oh dear. You are incorrect on the dialog. Your answer was clear. Nobody knows and there are many
variables that must be considered.
Thank you for your time and effort.

 

[Fast Eddie]

And of course we can add "are you going into steel or alloy"...
I guess Ill comfort myself with "even torque is more important than how much torque"

Even yes, and also to have a known ‘standard’.

If you torque to X and you know it works, then that’s all that matters in future, follow the tightening sequence and the standard torque.

 

[TBW]

Of course there’s also the aspect of calibration…as in do we all use regularly calibrated torque wrenches ?
or for that matter has “the” wrench ever been calibrated since we bought it?
just saying.

 

[marshg246]

If I had time to go fishing, I would be very interested in a can of worms.

This subject has been well covered by actual experts. Also, by Norton engineers quoting actual experts. See the MK 3 Workshop manual (00-4224), page 17.

I am not an expert on this subject. However, what I think is encapsulated here and I update it as new info is found: https://www.gregmarsh.com/MC/Norton/NortonTorque.aspx

In my testing, lubrication allows things to turn more and therefore provide more clamping pressure. Torque is how hard it is to turn - which is a surrogate for clamping pressure. An example: Exhaust nuts gorilla tightened with the AN tool rotate to a certain position. Unscrew and put a small amount of nickel anti-seize on the threads and use the same gorilla pressure and the nuts will rotate an extra 1/2 to 3/4 turn increasing the clamping pressure. They never come loose for me.

Then there's simply practical. For a long time, Triumph specified the stretch of the conrod bolts rather than torque and to replace the bolts and nuts each time. Can you imagine how long that took on the assembly line and how wrong it could be after each micrometer drop? And how it was followed by Joe Bob the dealer. So, they switched to torque with reused bolts and new nuts. Much faster, no issues, and they were still getting them equally tight which, IMHO, is what's important once tight enough.

 

[worntorn]

Just to add to the confusion we have Norton experts Mick Hemmings and Norman White using full torque settings as per the big White book and lots of lube on the threads.

My own take on it is that the table on page 17 is a general use table. Values there are listed as dry.
Does that mean that the individual values listed in the various sections of the manual are also dry?
I'm not sure as it doesn't say.
Apparently Mick and Norman think not.
Iirc Jim Comstock is also in the full torque when oily crowd.


Glen

 

[Ian James]

Try this. Get a bolt,say 1/2" dia fine thred,old head stud would do good and stand it in a vice place a heavy spring over it, valve springs inner and outer would be ideal top them with a washer and then the nut. Use the tension wrench to tighten,adjusting the setting so the spring just moves when the wrench brakes and record the setting. Disassemble and apply lube to the thread and repeat the tightening and adjusting to spring movement and record. That will tell you the difference. Hope that helps.

 

[Matt Spencer]

Putting the head on a 2 litre o.h.c. Ford engine , going in four or so stages , double each ( go round twice ) I Dropped the Tourque Wrench ,
At the first bolt of the final 80 Lb stage.
And Caught It .
One of the ' CLICK ' type .
At theb last bolt the allen head bolt ( six point ) socket slipped . This has given me a KEEP A SET OF BEST SOCKETS complex . And Bolt Heads .
12 point preferable ! .
ANYWAY ;
looking at the WRENCH , then , it was on 98 ( NOT 80 ) as , when Id caught it , The slider had Slid . evidently .
Bit Late to do anything as the olde socket was past it . SO 98 It Stayed .

The Moral of This story is , Shell be Wright . One can get a bit hysterical on such maters .

Inspecting theyre CLEAN & lubed . And the Bolt holes arnt oil filled to HYDRAULIC the BOLT before it bottoms ;
The Aircraft Mechanic Working as a BIKE MECHANIC Never Used a Tourque wrench .
Everyday ' wrenching ' you get a FEEL for the BOLTS ; and can feel their action . This is why its best not to be drunk .

Id Think , head faces & gasket cleaned & prepped , Going Down in a least FOUR stages ,
just nipped , pulled in , pulled down , Final last ' stretch ' . Covers It EVENLY .

Bolt torque Settings are " LUBED " according to the scornfull Engineer Trained salesman .
Not saturated .
With clean paper abounding ( to toss as its contaminated - best use for newspapers ! )
One may pour oil on the bolts ! rotate and oscillate ! them , for FULL COVERAGE , beforehand .
And leave them for 20 minutes or a half hour , to ' drain off '.
Likewise ' The HOLES ' maybe WD 40 spray , or pour full & invert engine to drain ,
checking with a flashlight or cotton wad on a dowl , or whatwever .

but the objective is none unlubed . Unless your using Locktite . More than 3 drops and your stuck .
Next Time you come to undo it .

Copper Coat is marvellous for Exhaust Freds , but it still gets roasted out . Have been known to
use it , or copper lube spray , on bolts n oles n fings .

Dont freak out , get all fingertippy , on the wrench , or half finger length on trucks wot need half in drive , for their more abundent tourque figures .
or sometimes two hands and both feet . With 3/4 drive .

Ounce inches is Just Finger Tip ' nipped ' ( seated ) Zero ' pull ' in the bolt / nut .

Foot Pound is when you start stretching them down .

So NIPPED ,ALL
SEATED ,ALL
Half Stretch EVEN , All.
10 Lb or so ( 5 or 8 or 10 depending on how many Lb-Ft. ) Of Full Stretch . ALL .

Bring Up Tom Full Stretch , in correct sequence . Re Apply . maybe reverse Seq. Test . ALL
come back in five minutes - Go Over in Correct sequence - to see if its ' settled ' at all . ALL .

DONE . Within 5 Lb is fine , less if unthrashed , more if Throttle ' ON ' is On the Stop , regularly.

Bring em Down again after a few heat sequences ( Rides ) then at 50 , before you open it up .
On Overhaul , again at 500 . As you havnt opened it up by then ! , and shouldnt ( Hold it Open ) till 2000 Miles . or 5000 if your a model of restraint , or growing old .

 

[marshg246]

Just to add to the confusion we have Norton experts Mick Hemmings and Norman White using full torque settings as per the big White book and lots of lube on the threads.

My own take on it is that the table on page 17 is a general use table. Values there are listed as dry.
Does that mean that the individual values listed in the various sections of the manual are also dry?
I'm not sure as it doesn't say.
Apparently Mick and Norman think not.
Iirc Jim Comstock is also in the full torque when oily crowd.


Glen

Glen,

Hidden away in what I said, I'm "generally" a full torque guy and if stainless is involved, there will always be nickel anti-seize or blue Locktite depending on the situation. That said, I'm very careful about fine threads into alloy. I do not agree with some of the modern-day experts in some areas but all my beliefs on torque are in writing for all to see. If it helps, great - that's why I maintain the page. Anyone who thinks I'm wrong about something is invited to discuss it with me or simply ignore my work. As I say in the header, most of the data did not come from me.

 

[marshg246]

Copper Coat is marvellous for Exhaust Freds , but it still gets roasted out . Have been known to
use it , or copper lube spray , on bolts n oles n fings .

I use Permatex Nickle anti-seize (75343) on the Norton exhaust nut for that reason. It's higher temp and if any does come out it's not very noticeable and easily cleans up with denatured alcohol. The key is to use a tiny amount. About a pea size per nut.

 

[marshg246]

Unless you know the conditions the factory used then the torque figures are mute anyway. Even if you do know and add a lube, which lube and what affect does that lube have. Unless you have access to both ends of the fastener so you can measure stretch its all guess work. You are looking to stretch the bolt within its elastic range and not go into the plastic range, so you need to know the material the bolt is made from too.

Bolt Nut Recommened Torque Table for SAE Grades

The following suggested tightening torques provide an excellent starting point for determining torque requirements.

www.engineersedge.com

Agreed, but on top of that, AFAIK, most fasteners were cadmium plated back then and zinc plated today. So, clean and dry back then does not mean the same thing as clean and dry today for standard fasteners. Also, the table you provided appears to cover un-plated SAE nuts an bolts. SAE threads are not the same a BSW, BSF, BSC, BA, and so on.