Lubricate bolt threads - graphite?

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fiatfan

fiatfan

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I´m finally completing the reassembly of the upper part of my 850 motor, and I´m using Norman White´s book for help and tips since I haven´t done any work on a Norton in a long time. I´m just about to put the cylinder and head back on, and reading about Normans way of doing this I get a little confused. He say´s you should use a graphite (graphene?) based grease on all the threads but doesn´t mention anything about the torque settings. Can you grease the threads and use the standard torque settings? Will that be correct? I mean he should know what he talks about, yes? (I´m not sure I´ll use a torque wrench, never did back in the day, but we´ll see.)
I´m also having trouble finding grease with graphite, but that I can probably fix. (Small town problem)
 
Strictly speaking, unless the specs call for lubrication (and state the specific type of lube), the bolt torque spec is for dry/clean fittings. If you lube the bolts as you describe and torque them to the (dry) spec, the lubed bolts will be overtorqued by at least 30%.

Does it matter? Well, that depends. If it's a steel bolt in steel or cast iron, probably not but if it's into aluminum, it could easily cause stripped threads. OTOH, I would have no difficulty following the advice of a known mechanic who has done a lot of work on specific engines though seeing a torque recommendation would be nice! Are you sure that the book doesn't cover torque specs somewhere? I've heard the name but am not familiar with Norman White's book. Seems odd that a "famous" mech wouldn't mention something about torque specs, even if he said he doesn't pay any attention to them!

Of course, in the old days nobody used a torque wrench anyway...An experienced mechanic would tighten fittings based on whether he felt they needed to be "hand tight," "moderately tight" or "really tight." :D
 
i'm thinking the general rule of thumb, when using a thread lubricant, is to DECREASE the torque spec by 20%
 
I'm with Mexico Mike all the way .. If the spec does not call out lubricated ...don't . There are just too many variables that may cause you grief . What grease are you going to use ?? What grade oil are you going to use ?? Every different type or grade will give you a different result and you all know what that means ..................... Yep !!! another oil thread but this time for hardware .

While these old bikes could have used some better engineering at the time ..... they have made it through 50+ years and mostly by the original numbers set out at the time .
 
Ron Hulton said:
So what was the name of the bar you did your extensive research in. I have a few things to figure out . ;)
Click to expand...
Happy to report I wasn’t the one doing the research and testing - but I did have to sit through the 2 hour after action report - what a snooze-fest… amazing what some people will debate.

But when you are building defense vehicles for the gov, everything has to be documented ad nauseum….
 
In addition to what others have said, with the exception of stainless or when specified, nothing should be used. Grease, oil, anti-seize, locktite, etc. all make nuts and bolts easier to turn and therefore reduce the torque needed. I'm not a metallurgist or mechanical engineer but I have studied this quite a bit and the results of that limited knowledge are summed up in the first page here: https://www.gregmarsh.com/MC/Norton/Norton Commando Torque.pdf
 
I believe ARP sells a specific lube product for their head bolts etc and give a torque percentage figure when using it.

Unless you are very experienced with hand/finger torque feel, then highly recommend a good torque wrench for the head bolts, esp the three downward studs in the alu head. Mr Comstock has a few videos out showing thread pull out failures of these three studs at torque levels of not mush more than the 30 ft-lbs spec.

Since these three studs are at a location impossible to fit a torque socket wrench on, i've used a ring spanner (7/16" SAE) and the Motion Pro right angle torque wrench spanner adaptor:

Adjustable Torque Wrench Adapter - Motion Pro

Motion Pro - High quality cables, tools and controls for motorcycles, ATVs, snowmobiles and personal watercraft.
www.motionpro.com www.motionpro.com
 
i would like to throw this out, FWIW - NEVER over-torque stainless hardware. ALWAYS use a torque wrench. most common stainless is rated somewhere between grade 2 and grade 5, and is less forgiving than steel, therefore the over-torque thing. NEVER substitute stainless for grade 8.
 
joe czech said:
i would like to throw this out, FWIW - NEVER over-torque stainless hardware. ALWAYS use a torque wrench. most common stainless is rated somewhere between grade 2 and grade 5, and is less forgiving than steel, therefore the over-torque thing. NEVER substitute stainless for grade 8.
Click to expand...
And stainless into stainless nuts etc can gall and basically weld itself together, so in those situations it is best to use a lubricant of some kind.
 
The figures for friction on fasteners state that over 90% of torque is used to overcome friction. Approximately 50% under the head and 40% on the threads. It is obvious that any lubrication will greatly reduce the torque required to stretch a bolt properly
 
I am only a layperson here so am not going to join in the technical debate.

Personally, I have always used some kind of lube, copper slip, graphite, etc on fasteners that require frequent torquing (like head bolts) mainly to prevent seizing etc and make the re torquing easier / better.

I haven’t reduced torques due to this. And generally speaking, haven’t had any issues caused by this that I’m aware of. Maybe the torques that we are using are so low as to be a little academic? Maybe it’s a bigger issue on oil rigs, heavy plant, etc?!

However, IMHO it seems like ARP have done the donkey work and made it easy for laypersons, and in future I’ll use their lube and figures.
 
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Fast Eddie said:
I am only a layperson here so am not going to join in the technical debate.

Personally, I have always used some kind of lube, copper slip, graphite, etc on fasteners that require frequent torquing (like head bolts) mainly to prevent seizing etc and make the re torquing easier / better.

I haven’t reduced torques due to this. And generally speaking, haven’t had any issues caused by this that I’m aware of. Maybe the torques that we are using are so low as to be a little academic? Maybe it’s a bigger issue on oil rigs, heavy plant, etc?!

However, IMHO it seems like ARP have done the donkey work and made it easy for laypersons, and in future I’ll use their lube and figures.
Click to expand...
I'm with you.

Stainless into anything needs some form of lube or you risk galling. Where not otherwise specified I use an old tin of silver stuff I have had for years and can't remember what's in it, nickel maybe?

I use copper grease in many other non-stainless applications. Always helps the next strip down.

I also have some of the stuff that comes with Jim Schmitt's rods, specifically for the rod bolts, a grahpite grease of some sort! I'm sure it is branded, but can't remember which!

But getting back to Norman White, talking to him about bottom end assembly I discovered that he, like me has used and swears by 'Graphogen' as an engine assembly lube for years, big ends, mains, cam bearings, followers and lobes and the like. His book confirms that.

Graphogen is graphite in a very heavy oil, I don't know if he uses a sear of the same stuff on threads, but I think it isn't far different to the stuff I got with the rods in a thread application, the purpose of the grease or oil is to put the graphite where you want it!
 
SteveA said:
I'm with you.

Stainless into anything needs some form of lube or you risk galling. Where not otherwise specified I use an old tin of silver stuff I have had for years and can't remember what's in it, nickel maybe?

I use copper grease in many other non-stainless applications. Always helps the next strip down.

I also have some of the stuff that comes with Jim Schmitt's rods, specifically for the rod bolts, a grahpite grease of some sort! I'm sure it is branded, but can't remember which!

But getting back to Norman White, talking to him about bottom end assembly I discovered that he, like me has used and swears by 'Graphogen' as an engine assembly lube for years, big ends, mains, cam bearings, followers and lobes and the like. His book confirms that.

Graphogen is graphite in a very heavy oil, I don't know if he uses a sear of the same stuff on threads, but I think it isn't far different to the stuff I got with the rods in a thread application, the purpose of the grease or oil is to put the graphite where you want it!
Click to expand...
Molybdenum is a great anti-galling/anti-seize chemical

Molybdenum Disulfide -The Ideal Solid Lubricant and Anti-Galling Material | Valin

Molybdenum disulfide is a naturally occurring blackcolored solid compound that feels slippery to the touch. It readily transfers and adheres to other solid surfaces with which it comes into contact.
www.valin.com www.valin.com

JS rods are Carrillo rods that comes with their bolt lube which i believe is a Molybdenum base

And regarding the precision of torquing wet fasteners, wonder how many torque wrenches out there are uncalibrated?
 
To be fair to torque wrenches everywhere, great and cr@ppy - one of the most important things a torque wrench can do is to tighten all the fittings to the same torque...whether it's the "correct" torque is a different issue. Many problems - especially with head gaskets...and even wheel lug nuts are avoided if the relevant fittings are tightened in the proper sequence and are equally tight to avoid warpage.

Wheel lug nuts? Yep, I have seen many instances of brake-pedal pulsation due to warped rotors eliminated by simply loosening the nuts and retightening them in proper sequence using a torque wrench.
 
Hi all,
With my sheds full of ageing farm machinery which requires plenty of maintenance and is only used seasonally and a garage full of (mostly) old pommie cars and bikes, I put anti-seize on all external threads and a lubricant, varying from engine oil to moly products, on all internal threads.
to date I have had no particular problems. Certainly not with cylinder heads etc where I perhaps incorrectly both lubricate and torque to book value.
The anti seize is oh so appreciated when revisiting fasteners that I haven’t removed for years and look like they will be stuck fast but undo without difficult, particularly on my boat.
 
One point I’d like to repeat to those who favour dry fasteners…

Unless you clean both male and female threads scrupulously, with a solvent of some kind, you don’t have dry threads anyway!

Old threads (especially female) will have all sorts of unknown stuff in there, new threads will at least have machining lube residue, and / or corrosion protection, etc.

So unless you scrupulously clean all threads, you ain’t assembling with dry threads, even if you’re intentionally deciding to not use a lubricant.
 
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