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seattle##gs · 2026-02-15T01:04:11-0700

When installing the 3 head studs do you bother torqueing them or just guess at it? I've never known the answer. I usually use red locktite, a moderate amount of pressure, and hope the red loctite does not burn out.

SteveBorland · 2026-02-15T04:33:24-0700

I replaced them with the ARP headbolt set from Jim Comstock - they have a different thread which works far better than the original fine thread form, so no worries about stripping. As I recall, he includes a torque setting with the kit. A far better solution in my experience.

SteveA · 2026-02-15T04:34:21-0700

Unless I misunderstand you are talking about screwing the studs into the aluminium head, assuming you don't have helicoils or inserts, though that makes no difference.

Anything more than making sure the stud is fully threaded in risks pulling the thread in the head. As such, you can't torque a stud.

Of course you can torque a nut on the stud when the head id on the barrel. If you are talking about torquing the nuts the critical issue is having a tool that fits and allows accurate torque. It might be nice to do, but it isn't essential to torque them and many don't.

Nortoniggy · 2026-02-15T05:13:07-0700

If you lock two nuts together on the stud you could use a torque wrench. As you say there is no published torque though. I just make sure they are nipped up and don't use any sort of thread lock. I would have thought tightening them quite tight might risk the threads in the head and/or raise that metal slightly around the stud.

marshg246 · 2026-02-15T08:09:46-0700

seattle##gs said:
When installing the 3 head studs do you bother torqueing them or just guess at it? I've never known the answer. I usually use red locktite, a moderate amount of pressure, and hope the red loctite does not burn out.

There is a lot to know on this subject. Please read to the end: https://gregmarsh.com/MC/Norton/Info/HeadStudStudy.aspx

I always put studs in aluminum with blue threadlocker (243). My primary goal being so the next guy doesn't have the stud come loose when removing the nut. If the stud is stainless, that also works as an anti-seize. I "feel like" it also tightens the stud to aluminum threads but that's probably not true.

I don't/won't use red threadlockers - too many times taking apart bikes where someone used it. Takes way too much heat to release to get things apart without damage and not using the heat will bring the threads out of aluminum if you don't know it's in there and try too hard. Also, IMHO, it's not good to heat things like cases to the red release temp.

So, I use blue threadlocker (243), double-nut, and snug them, no torquing.

BTW, just saying the color is not enough:

Grandad · 2026-02-15T08:28:39-0700

Useful chart for the unitiated ^^^^

Years back we had the Loctite rep in our engineering workshop and we demo'd the various strenghts - bolt in a vice and nut loctited to it.

The hand tool removal types were more than up to the job and despite their " tag " of hand tool removal a surprisingly decent grunt on a wrench was needed to remove the nut.

The heat removal types are for serious use only - we needed to use an oxy - acetylene torch on the nuts to remove them.

Schwany · 2026-02-15T09:23:09-0700

This is babble mostly: 3/8"-16 inserts in the head, then the appropriate studs. I'm using cNw head studs. cNw head studs are tightened down into the head with an allen wrench. Allen socket wrench if you have them. The studs are probably ARP parts. I tighten the studs down with a common sense specification. I use either ARP thread goop on the threads or Blue loctite (can't remember which) and crank them down. Since old Norton heads are made of hummingbird egg shells and silly putty not using inserts for those 3 studs in the head can be risky business. Only real difference between what I do and what you are doing is I don't use Red loctite on soft aluminum.

Stephen Hill · 2026-02-15T10:36:31-0700

Every time I turn on an auto rebuild/fixit tv channel I am bombarded by ARP ads masquerading as testimonials/recommendations. They must have an amazing advertising budget.
Apparently the world as we know it will fall apart if we don't reassemble our Nortons and everything else with ARP hardware.
I guess I am getting the religion a little late in the game.
Am I missing something?

seattle##gs · 2026-02-15T10:38:38-0700

These are special JS studs with inserts. They work very well and I would use them again. So I would guess about 10 - 15 PSI into the head (done by feel), blue loctite next time.

Schwany · 2026-02-15T11:21:31-0700

seattle##gs said:
These are special JS studs with inserts. They work very well and I would use them again. So I would guess about 10 - 15 PSI into the head (done by feel), blue loctite next time.

You better like them, they cost enough. Particularly if you bought the JS 3/8"-16tpi Time-Sert kit as well. Yowser!!

It is a nice kit though.

Schwany · 2026-02-15T11:38:27-0700

Stephen Hill said:
Every time I turn on an auto rebuild/fixit tv channel I am bombarded by ARP ads masquerading as testimonials/recommendations. They must have an amazing advertising budget.
Apparently the world as we know it will fall apart if we don't reassemble our Nortons and everything else with ARP hardware.
I guess I am getting the religion a little late in the game.
Am I missing something?

I'm thinking the world is falling apart without any special fasteners.

Most of the fancy hardware is not aimed at stock Norton engine rebuilds. I doubt you are missing anything if not using it. The stock hardware works. It's just not as expensive, pretty, or as easy to use doing a rebuild. 12-point nuts are a time and potential frustration saver for me. I can't speak for anybody else though.

TJBaker57 · 2026-02-15T12:09:00-0700

seattle##gs said:
So I would guess about 10 - 15 PSI into the head

PSI ??? (yes, I am a nit-picker)

I am neither a machinist nor an "engine builder".

As I understood it, torque is a way of gauging/measuring bolt or stud stretch, no??

Where is the stretch in installing a stud into a component such as a head or cylinder block?

Is not the end goal here just to be certain the stud is bottomed out in the threaded hole? Is not anything beyond that stretching the threads in said threaded hole?

Maybe that IS the goal here? To add a little stretch to those threads kind of like a pre-load??

MexicoMike · 2026-02-15T12:29:21-0700

One thing that is often overlooked when buying "better" (?) fasteners is that the OEM torque settings could be VERY wrong. For example, if a grade 2 bolt is used in the factory setup and you "upgrade" to a set of grade 5 bolts, the factory torque setting will be much too low and there will be no "stretch." This could cause the fitting to loosen due to normal vibration.

OTOH, if you find the "correct" torque for a grade 5 bolt/nut of the appropriate size and apply that, it could damage/warp the components involved...which may not have been designed to accept that much clamping pressure. Look at most AMAL carb flanges on these old bikes to see a small scale example of the typical "too much clamping pressure"/subsequent warping. Same thing can happen with almost any component.

WEM · 2026-02-15T12:37:30-0700

marshg246 said:
There is a lot to know on this subject. Please read to the end: https://gregmarsh.com/MC/Norton/Info/HeadStudStudy.aspx

I always put studs in aluminum with blue threadlocker (243). My primary goal being so the next guy doesn't have the stud come loose when removing the nut. If the stud is stainless, that also works as an anti-seize. I "feel like" it also tightens the stud to aluminum threads but that's probably not true.

I don't/won't use red threadlockers - too many times taking apart bikes where someone used it. Takes way too much heat to release to get things apart without damage and not using the heat will bring the threads out of aluminum if you don't know it's in there and try too hard. Also, IMHO, it's not good to heat things like cases to the red release temp.

So, I use blue threadlocker (243), double-nut, and snug them, no torquing.

BTW, just saying the color is not enough:

View attachment 123781

Would it be safe to assume that the same technique, ie. blue loctite 243 and no torquing, also applies to the rocker cover studs?

Stephen Hill · 2026-02-15T12:57:45-0700

TJBaker57 said:
PSI ??? (yes, I am a nit-picker)

I am neither a machinist nor an "engine builder".

As I understood it, torque is a way of gauging/measuring bolt or stud stretch, no??

Where is the stretch in installing a stud into a component such as a head or cylinder block?

Is not the end goal here just to be certain the stud is bottomed out in the threaded hole? Is not anything beyond that stretching the threads in said threaded hole?

Maybe that IS the goal here? To add a little stretch to those threads kind of like a pre-load??

Tightening a stud into a casting does not typically result in the stub bottoming in the threaded hole. It might bottom. But usually all you are doing is mushing the unthreaded section of the stud into the top of the internal threads.
When you think about it, it is a pretty crude method.
So there is no stretch because you are not tensioning the stud.
This is one good reason for using loctite.
Or just use a very light hand on the wrench, in the knowledge that you are deforming the first thread in the casting and it will probably unscrew next time you disassemble. From a practical matter, it doesn't matter.
Unless you are dealing with a through hole and are concerned about oil or water migrating along the theads.

marshg246 · 2026-02-15T14:27:38-0700

WEM said:
Would it be safe to assume that the same technique, ie. blue loctite 243 and no torquing, also applies to the rocker cover studs?

I said: "I always put studs in aluminum with blue threadlocker (243)." So, yes.

robs ss · 2026-02-15T14:37:18-0700

There is no reason to torque these studs. They are not clamping anything. You just want them to stay there, and as @marshg246 said, medium strength Loctite will do that well.
You do want to ensure both the male and female threads are clean and dry to allow the Loctite to do its job.
Cheers

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