Anti-seize on head nuts

[JW113]

One thing that always bothers me a little is when you go to loosen the head nuts on a Evo Twin Cam, they twist-twist-twist until they make that loud CRACK then let loose. I've always used motor oil on the cylinder stud threads when installing the heads. I'm wondering if anti-seize is OK to use, and if it might make getting the nuts back off later a bit less dramatic?

-JW

[wfolarry]

The heat sucks out whatever you put in there so don't over think it. Besides thay dryness keeps them from backing off when you're riding the bike. 

[kd]

Using a lube on the threads will also lead to an over torqued fastener.  Follow the OEM procedure or someone like Cometic with their gaskets and all should be good. 

[rbabos]

Using a lube on the threads will also lead to an over torqued fastener.  Follow the OEM procedure or someone like Cometic with their gaskets and all should be good.

One of the reasons I like the x pre torque plus the 90* rotation. Can't over torque this way and it uses the degrees for stretch rather then more or less thread and head bolt contact frictional differences that skews actual torque values the wrench alone gives. Cometic not immune to this effect. Just saying.
Ron

[JW113]

Agree Ron, I don't use torque either for the same reason on the head nuts. Pulled too many studs with the Cometic/James method.

-JW

[nibroc]

what is an evo twin cam?

[86fxwg]

ARP Ultra Tourqe.   https://youtu.be/SSgG5xClye4


86


         

[klammer76]

Using a lube on the threads will also lead to an over torqued fastener.  Follow the OEM procedure or someone like Cometic with their gaskets and all should be good.

One of the reasons I like the x pre torque plus the 90* rotation. Can't over torque this way and it uses the degrees for stretch rather then more or less thread and head bolt contact frictional differences that skews actual torque values the wrench alone gives. Cometic not immune to this effect. Just saying.
Ron

Agree Ron, I don't use torque either for the same reason on the head nuts. Pulled too many studs with the Cometic/James method.

-JW

Are you guys saying you use the OEM service manual 90* final rotation procedure when using Cometic MLS head gaskets also?Thanks

[Maddo Snr]

Using a lube on the threads will also lead to an over torqued fastener.  Follow the OEM procedure or someone like Cometic with their gaskets and all should be good.

I've been in the trade 44 years and I've never heard that one KD. Unless stated, general torque specs are for clean, lubed threads. Are Harley specs different? i.e. dry?

It is the tread angle that creates thread locking not the lack of lubrication (stiction) between thread faces. A square buttress thread on a vise is covered in grease and NEVER backs off...

Dry threads end up under-torqued, not over, because the torque wrench is seeing stictional load as torque. Dry threads are indeed an issue, for under-torqueing.

For the OP: On race motors we use a 50:50 mix of hi-temp 'never sieze' and lanolin grease. It keeps the fasteners and threaded holes in perfect order. Works fine with air-cooled heads. Just be sure you don't re-use ELD fasteners!

p.s. The "setting torque + 90 degrees" method is mostly for elastic (generally re-usable) fasteners, the "setting torque plus finishing torque" method is mostly for plastic (ELD) fasteners, all of which are single-use. Compensator centre-bolts being an example of the latter. Both types should be clean and lightly lubed before pulling up, unless they have a manufacturers lock-lubricant already applied.

As KD sagely said "Follow the manufacturers procedure".

[Mick0311]

There are different torque specs for dry, lubed or PTFE fasteners.

[kd]

Using a lube on the threads will also lead to an over torqued fastener.  Follow the OEM procedure or someone like Cometic with their gaskets and all should be good.

I've been in the trade 44 years and I've never heard that one KD. Unless stated, general torque specs are for clean, lubed threads. Are Harley specs different? i.e. dry?

It is the tread angle that creates thread locking not lubrication between thread faces. A square buttress thread on a vise is covered in grease and NEVER backs off...

Dry threads end up under-torqued, not over, because the torque wrench is seeing sectional load as torque. Dry threads are indeed an issue, for undertaking.

For the OP: On race motors we use a 50:50 mix of hi-temp 'never sieze' and lanolin grease. It keeps the fasteners and threaded holes in perfect order. Works fine with air-cooled heads. Just be sure you don't re-use ELD fasteners!

p.s. The "setting torque + 90 degrees" method is mostly for elastic (generally re-usable) fasteners, the "setting torque plus finishing torque" method is mostly for plastic (ELD) fasteners, all of which are single-use. Compensator centre-bolts being an example of the latter. Both types should be clean and lightly lubed before pulling up, unless they have a manufacturers  already applied.

Maddo Snr, I have come to respect your opinion and input on this site. I will however choose to disagree with you on this.  You also seem to agree with me by interjecting some engineering principals that I don't see as totally relevant here. All fasteners will incur longitudinal stress when tightened passed their given yield point dependent on their makeup. That stress can cause them to exceed their yield point.

I too have a long background, albeit not as extensive as I suspect yours is, (48 yrs certified in the trades. 13 years training, investigation and enforcement surrounding failures, and 19 years of ongoing consulting and giving expert evidence in court the whole time)  My findings are, and supported by manufacturers, that a clean thread is required, A "drop" (very subjective term) of lube at the start of the thread is important to prevent the "under torque" condition you and I agree to. However, a well (or over) lubed thread will result in an easier turn on the wrench to the risk of over yield on the fastener material probably ending in damage.  I understand the engineering principal in the fact that sum of the thread base engauged within in the length of the fasting bore is ideally at least equal to the width of the fastener stud component. (thinner nuts can only sustain lesser torque)  Deformation of the threads most usually occurs when the nut for example in reduced in height and can not support the tension. Deformation is the result of exceeding the yield strength of the material. Stretch adds resilience and exceeding stretch beyond yield removes that safety factor.  Repeated hot and cold cycles can also cause fasteners to loosen and stretch provides thread traction that prevents that.  Over lubing threads removes that locking principal in most thread designs.

Coarse and fine threads also come into play as they have different ramps speeds and therefore different locking qualities. I do agree that it is the thread angle that creates the thread locking and not the lubrication. Lubrication allows threads to travel easier in both directions under most conditions (similar to too steep a pitch of thread will unwind easier).  I used to wonder why my eaves trough screws on the south side of my house would wind out and drop to the ground if not re-tightened until I realized the hot and cold of the sun in winter (only on the east, south, and west where exposed) is when and where it happened and the steep wood screw thread pitch was part of the phenomina. Vibration over time in the common definition or by hot and cold response can be the culprit. 

A reasonable comparison for what we are discussing might be automotive and large truck wheel fasteners. (some even have tapered seats assisting them)  Please take the time to look up the manufacturer's recommended procedure if you want.  All manufacturers of such fasteners recommend what I have just explained as a drop of oil to the beginning of a clean thread on installation (and under the washer if so equipped). Torque specs are based on this preparation before installation. The oil is meant to reduce / prevent galling and drag only. Over torquing due to excessive lube will stretch these fasteners to the point that they will crack the stud in the valley of the thread's sharpest point and fracture. I can not tell you how many times I have investigated wheel detachments that had clear evidence of a thread soaking on a recent installation that caused stretched studs with a measurable loss in cross section dimension at the fracture point.  In fact, I carry several examples with me for visual training purposes.

I hope this helps explain my point of view. As for what do I do?  Almost without exception it is what I describe unless the manufacturer insists on other methods such as the 90* method. There can be different torque specs that relate to the material / application involved or the thread pitch etc..

[Barrett]

https://www.sscycle.com/docs/default-source/instruction-sheets/51-1044_headbolts84-99bt86-03xl_20120730.pdf?sfvrsn=4
S&S says light coat of lube.

[Maddo Snr]

Great stuff KD. I had to think about the wording. Over here 'investigation and enforcement surrounding failures' is called "tribology" and 'yield point' is "elastic limit'  all good.

Re: oiled threads. All modern motorcycles, but especially those used in damp humid climates, salted roads and off-road suffer from electrolytic (and to a lesser extent heat-based) corrosion of fasteners. I've only been playing with HDs for 18 months but I find the level of fastener corrosion on HDs to be worse than anything I've ever seen on dirt/race bikes. Almost marine type damage.

Invariably motor and lower chassis fasteners are the worst. I'm of the opinion that with HDs particularly, under tightening of fasteners due to thread stiction is a major issue.

I'm constantly torquing race-bike aluminium-alloy and Ti fasteners which have very high levels of stictional grip to their threaded holes. Obviously they need to be properly lubricated or the torque wrench beeps too early.

I've also done a fair whack of consultant tribology over the years, mainly to do with lubrication failures. I have no knowledge of over-lubrication of threads causing fasteners to back out. I can see that it may be an issue though, especially in the case of PTFE contamination.

I had hoped to happily retire and not think about Engineering ever again. Thanks for nothing! 

[Maddo Snr]

https://www.sscycle.com/docs/default-source/instruction-sheets/51-1044_headbolts84-99bt86-03xl_20120730.pdf?sfvrsn=4

S&S says light coat of lube.

Lets be clear here, "a light coat of lube" is a quick spray of 5-56 and a light wipe-down with a clean rag, not greased or dripping in lubricant.

[kd]

 

https://www.sscycle.com/docs/default-source/instruction-sheets/51-1044_headbolts84-99bt86-03xl_20120730.pdf?sfvrsn=4
S&S says light coat of lube.

Lets be clear here, "a light coat of lube" is a quick spray of 5-56 and a light wipe-down with a clean rag, not greased or dripping in lubricant.

If you would have said that earlier I could have used the time for my lengthy response to work on my bike.   


  You're a funny guy Snr.  On the subject of electrolytic corrosion, I notice that HD uses the chassis fairly extensively in their circuits.  There's ground lugs and paths all over. Grounds are continually causing ghost issues.  I have often thought dissimilar metals and this wild current (and in some cases simple salt air contamination causing the electrolysis) was a contributor that may be the part of the problem that the OP began the post over.

How's that for getting back on track eh?   

[Maddo Snr]

Nice segue...and 100% agreed. Who was the genius at HD who said:
"Hey Earl, I'm a thinkin' we'all can save $2.59c on every bike if we ditch proper earthing by copper conductors and use the steel frame, zinc coated bolts, chrome brackets, and galvanised braces as a return current path"

No chance of electrolytic action there... 

I advised someone on HTT to bond their starter motor directly back to battery negative on a high-comp bike. He was amazed at the extra cranking speed!

Negative path return through the chassis/monocoque is a major cause of bolt corrosion. Individual low-impedance negative bonds made a massive difference to car corrosion around 1980. HD isn't alone, KTM race bikes are the worst for neg bonding issues.

[FSG]

Lets be clear here, "a light coat of lube" is a quick spray of 5-56 and a light wipe-down with a clean rag, not greased or dripping in lubricant.

a bit like Brylcream .......  "a little dab will do ya"   

[Maddo Snr]

My apologies for getting sidetracked, nerd Engineer syndrome.

re: the OPs 'loud crack' worries

The loud 'crack' one hears when breaking open a torqued bolt doesn't come from the thread! The thread is a ramp, a spiral ramp but still an incline. You never hear a 'crack' when a landslide starts, a kid releases to go down a slippery-dip or your bike rolls away on a hill.

The 'crack' is the breaking of the bond between the washer/bolt-flange and the sub-assembly. If the bolt ever fails during this procedure you'll notice the break is way up where the shank meets the bolt-head, rarely, if ever, down the shank or threaded section.

Made all the more worse by a steel bolt being electrolytically bonded to the alloy sub-assembly by years of galvanic action.

[Maddo Snr]

And another thing:

My HD manual says to prepare all fasteners by cleaning them with PJ1 contact cleaner leaving them clean and DRY.

All HD spare part unplated bolts are shipped lubed...

[TorQuePimp]

They need nothing more than oil.....I think there's Kendall racing oil in my oil can at the moment

No never seize.....no arp bolt poop......motor oil

And yeah the studs should be cleaned before applying oil

Pretty simple

[Ohio HD]

https://www.sscycle.com/docs/default-source/instruction-sheets/51-1044_headbolts84-99bt86-03xl_20120730.pdf?sfvrsn=4
S&S says light coat of lube.

Agree with that, and you. I just use a bit of motor oil between my fingers and rub it into the threads of the studs. Just to keep the faster and stud from having a galling condition.

Basically I just get them wet with oil, wipe most of it away with fingers, not a rag. 

[Chippitt68]

ARP Ultra Tourqe.   https://youtu.be/SSgG5xClye4


86


       

Did he say 18,000 lbs?

[speedzter]

I think we all know what the correct procedure is , but just including this video as I found it a good practical demonstration.

https://youtu.be/O96AUlIBkU8

[Maddo Snr]

They need nothing more than oil.....I think there's Kendall racing oil in my oil can at the moment

No never seize.....no arp bolt poop......motor oil

And yeah the studs should be cleaned before applying oil

Pretty simple

ARP 'bolt poop' is made for motors developing way north of 1000HP per cylinder. A very strong Harley makes less than 1/10th of that. Horses for courses I guess TP.

At Top Fuel level no-one uses a torque wrench on rod bolts, they're stretch-monitored with a dial indicator. The rod bolts are also pre-lubed. I remember Keith Black saying that only 15% of a torque-wrenches work stretches the bolt, the rest is thread stiction.

[PoorUB]

Did he say 18,000 lbs?

Yes, why do you ask?

I missed if the video claimed any application, but I believe 18,000 pounds is a bit more than what HD cylinder studs run, but close!

7/16"UNC if i recall?

I stand corrected. 3/8" UNC so not even close to the 18,000 pounds in the video, maybe about 1/2 of that.