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Allan,
as i said in a previous ( and equally long winded post) .... do you have any idea how much force it takes to strip say 1/2" thread in cast iron ( in good nick) ?

I suggest probably 3-5 times or so the specified torque

Now i dont have any issue at all with being wrong , but in my 50 years as a fitter/turner (and owning a component manufacturing business) i did learn a little

But clearly that knowledge cant compare to some 30 second google expert who quotes a mathematically incorrect site.

I always look at consequence of failure

slightly too tight the consequences are NIL .... under tightened = leaking/blown gasket and possibly head warping

don't worry im not getting all out of shape with all this stuff i am just aware that there will be those who go by what they read in this forum

Its on the internet so it must be true right hahhahahh


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Originally Posted by jakejoseph
Hi folks - installing a head for the first time on a 1967 BSA A65L. I've installed heads before, and the factory service manuals have always given guidance as to whether the bolts should be installed with lube or with not. What's best practice for these engines and installing the head bolts/studs.

Should I use anti-seize on the bolts/studs?
Should I install dry?
Should I install with 30wt.?

Any advice is welcome.

Hey jake (the OP), the factory service manual for my 1971 A65 gives no indication to lube the head bolt in any way. The 1967 manual should be followed IMHO whatever it states, no lube I suppose

I install head bolts in 3 incremental torque steps since the clamping torque of each subsequent bolt is influenced by the previous bolts torque. The cross pattern of bolt torqueing is important.

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yes .... bolting them down progressively as above IS very important!


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Originally Posted by Ignoramus
Allan,
as i said in a previous ( and equally long winded post) .... do you have any idea how much force it takes to strip say 1/2" thread in cast iron ( in good nick) ?

I suggest probably 3-5 times or so the specified torque

Now i dont have any issue at all with being wrong , but in my 50 years as a fitter/turner (and owning a component manufacturing business) i did learn a little

But clearly that knowledge cant compare to some 30 second google expert who quotes a mathematically incorrect site.

I always look at consequence of failure

slightly too tight the consequences are NIL .... under tightened = leaking/blown gasket and possibly head warping

don't worry im not getting all out of shape with all this stuff i am just aware that there will be those who go by what they read in this forum

Its on the internet so it must be true right hahhahahh

I’m not saying you’re wrong, I’ve had two barrels now which have not had the best threaded holes. The one I’m currently using I’ve since helicoiled on the 5x holes which don’t hold studs. These things are 50+ years old and no one knows what kind of a life they have had.


Life is stressful enough without getting upset over the little things...

Now lets all have a beer!

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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yep Allan, that is why i said "in good nick" regarding threads .... they sure have taken some misuse , most popular was threading in BSW (or a UNC for our American friends) into a BSF second only to cranking in a damaged burred bolt whilst saying " this is a tight one pass me the power bar"

all good


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
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The most common is UNF stuck into BSF threaded fittings or nuts.
'That's a fine thread, must be one of these.......'

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Originally Posted by NickL
The most common is UNF stuck into BSF threaded fittings or nuts.
'That's a fine thread, must be one of these.......'

been there done that in the 70s before i had even heard of 26 series .... trouble is that that bolt it is STILL on my A65 on the sliders , left hand rear ... i must get around to fixing it one day but no rush


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It was you in your previous post that mentioned 30% of failure rate not me, I would expect more than a factor of ~3 saftey for head bolts.
"Just of the top of my head i would bet that a pound to a pinch of *hit that the max torgue in book would only be ?? ....what??? .... 30% of the failure point."

If you wish to convince me that the maths in that link i provided are wrong i will require more evidence than you saying it is. I will want more than personal anecdotes and some ad homenim attacks though.

I'm not a "PHD mechanical engineer" Altough i do find it interesting that you imagine that a PHD mechanical engineers opinion would somehow be worth less than yours? are you a proffesor in mechanical engineering?

I'm a actually a development chemist at a company that makes lubricants including ...you guessed it anti siezes, and i can tell you that it is 100% a fact that clamping load increases significantly when anti seize is added to clean Fasteners for the same amount of torque because i've done the work myself. a little more than a "30 second google search".

BSA specified torque settings to ensure clamping load on the head would be consistent and at the level they decided would be correct, if you add lubricant to those fastners without calculating the reuction in torque required to maintain the same level of clampin load you are ignoring what the BSA engineers specified as the correct clamping load. At that point why follow the torque settings at all just eyeball everything.

As i said in my first post the Manuel should be followed as the engineers who designed these engines (more or less) knew what they were doing better than most of us throwing spanners at them 60 years later.

Scatter is a different issue, one which the designer would take into account and if they specified lubricated fastners they would spec the torque setting to the level that applied the appropriate clamping force IE reduced over a dry fastner.


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selectively quoiting is a wonderful thing.

regarding my PHD remark what i said was

"isn't the internet wonderful ... a bazar highly technical piece of tripe for all occasions probably written by some youth whit a PHD in mechanical engineering who has never held a spanner in his life ."

NOTE "some youth " Ive met plenty of graduate engineers who have zero practical experience .

regarding mathematical errors

please explain how you can have a 120% failure rate


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
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