Head torque procedure

[Andy Higham]

As title says,
I would normally torque to say 15LB, then 20LB, 25LB and finally 30LB
But the Norton has two nuts at 20LB. Would I ignore these after I reached 20 LB and just work on the other 8? or keep changing the settings on my torque wrench for these two?

 

[hhh]

You need to at least check that they don't move at 20 lb after the others are done to 30.

 

[htown16]

The bolts need to be torqued in a certain sequence. See your shop manual. The 20 ft/pd are the last to be torqued. Check them on your final torque circuit.

 

[Fast Eddie]

As title says,
I would normally torque to say 15LB, then 20LB, 25LB and finally 30LB
But the Norton has two nuts at 20LB. Would I ignore these after I reached 20 LB and just work on the other 8? or keep changing the settings on my torque wrench for these two?

No.

Follow the torque sequence.

Use lower figures for those 2 fasteners, ie get them all to 25 and 15 respectively, then finish them all off to 30 and 20 respectively. Keeping to the correct sequence all the time.

 

[marshg246]

There is conflicting information on the torque values. It is written up here: https://www.gregmarsh.com/MC/Norton/Info/NortonTorque.aspx

Also, #s 2, 7, 8 will likely pull out if you use the increased torque value stated in Service Release N3/68. If you have the original three studs, there a good chance they will be fine a 30 ft. lb. If you have replaced them with the ones AN currently offers, there is a good chance they will pull out at 30 ft. lbs. In the link I provided is a link to the service release and a link to a study I did on those three studs.

BTW, not blaming AN, they are making them to the drawings - it's just that the drawings are wrong.

It is a terrible feeling when one of those studs pulls and you don't own a machine shop or have a decent one nearby. Last time it happened to me and I didn't have a spare head of the right type, a bunch of begging got Jim Comstock to save me. I needed him because the local machine shop put the inserts in crooked!

 

[zotz]

It is a terrible feeling when one of those studs pulls and you don't own a machine shop

Bin there done that.

 

[Onder]

Im on that bus too. :-(

 

[laurentdom]

Hi All,

I need your help to remind when to re-torque my cylinder head after having installed a new (composite) head gasket.

The head is a RH10 with Molnar alloy cylinders (with helicoils), and Jim Schmidt studs / bolts / nuts.

Thks,

Laurent

 

[kommando]

A composite head gasket will need retorquing several times, first one after 50 miles and repeat at longer mileages until it stabilises.

 

[Fast Eddie]

I think the requirements can vary between different makes of gasket.

I was shocked at the amount of tightening the first time I rebuilt my Commando with a composite gasket, I actually thought the threads were pulling or similar!

I did this:

After the first start up (without riding).

After the first short ride.

Then at 50, 100, 500, 800 (ish) miles.

Basically, need to check the easy access ones very frequently, and if one is loose, check em all. And keep doing this until things stop moving.

If you have thread inserts in the head you could consider the cheat I was taught… over torque them by a few lbs initially. This really reduced the later crush and corresponding need for adjustment.

I wonder if the factory did this? Or were the gaskets they used different back then? There’s no way the composite gaskets I’ve used would have lasted 500 miles (ie to the first service on a new bike) without issue !

Cos I now run a 920 and a 1007 I have no option but to use copper head gaskets. These don’t require any re-torquing, they’re MUCH more stable, which is useful when trying to be precise about squish band clearances etc.

 

[marshg246]

I think the requirements can vary between different makes of gasket.

I was shocked at the amount of tightening the first time I rebuilt my Commando with a composite gasket, I actually thought the threads were pulling or similar!

I did this:

After the first start up (without riding).

After the first short ride.

Then at 50, 100, 500, 800 (ish) miles.

Basically, need to check the easy access ones very frequently, and if one is loose, check em all. And keep doing this until things stop moving.

If you have thread inserts in the head you could consider the cheat I was taught… over torque them by a few lbs initially. This really reduced the later crush and corresponding need for adjustment.

I wonder if the factory did this? Or were the gaskets they used different back then? There’s no way the composite gasket I used would have lasted 500 miles (ie to the first service on a new bike) without issue !

Cos I now run a 920 and a 1007 I have no option but to use copper head gaskets. These don’t require any re-torquing, they’re MUCH more stable, which is useful when trying to be precise about squish band clearances etc.

I'm starting to wonder if it's time rather than miles for re-torquing. I'm building two engines now and will fully torque them on the bench, and then once the bikes are together, torque them again. Then a short first ride and check them. Trying to determine if it is time, heat cycles, or time under load (miles).

 

[Fast Eddie]

I'm starting to wonder if it's time rather than miles for re-torquing. I'm building two engines now and will fully torque them on the bench, and then once the bikes are together, torque them again. Then a short first ride and check them. Trying to determine if it is time, heat cycles, or time under load (miles).

I had the same thoughts Greg.

 

[wildbill56]

Bin there done that.

Imagine that feeling on a flat 4 Lycoming or Continental. Result equals new case$ usually....don't know if inserts are approved...either way, $$$

 

[cliffa]

I had the same thoughts Greg.

Or thermal cycles?

 

[SteveBorland]

I have a A-N composite head gasket and Jim Comstock's stretch bolts. After building the engine, I've checked the head bolts about 4 or 5 times. On the first retorque, it was less than 1/8 turn, since then nothing at all.
This on a 750 head converted to the 850 head stud spacing.
Very happy with the results!

 

[laurentdom]

Thks mates. Enjoy your safe & no-leak rides in 2026 !

L.

 

[ashman]

Using a copper head gasket i torque down on rebuild then do 500 miles and retorque then leave alone, 15 years now and haven't touched it, but if i get a slight seep then i retorque, so far all good, i have a freak Norton, been so good to me.

Ashley

 

[DennisMo]

When you retorque do you loosen the first (ie number one) and then tighten it in two stages to full torque, then move on to the next?
I might have read somewhere that someone just checks the torque of the unloosened nut (say 30 foot lbs) to see if it moves.
Thanks
Dennis

 

[marshg246]

When you retorque do you loosen the first (ie number one) and then tighten it in two stages to full torque, then move on to the next?
I might have read somewhere that someone just checks the torque of the unloosened nut (say 30 foot lbs) to see if it moves.
Thanks
Dennis

I do not. I simply tighten to the correct torque.

 

[daveforty]

I think the requirements can vary between different makes of gasket.

I was shocked at the amount of tightening the first time I rebuilt my Commando with a composite gasket, I actually thought the threads were pulling or similar!

I did this:

After the first start up (without riding).

After the first short ride.

Then at 50, 100, 500, 800 (ish) miles.

Basically, need to check the easy access ones very frequently, and if one is loose, check em all. And keep doing this until things stop moving.

If you have thread inserts in the head you could consider the cheat I was taught… over torque them by a few lbs initially. This really reduced the later crush and corresponding need for adjustment.

I wonder if the factory did this? Or were the gaskets they used different back then? There’s no way the composite gaskets I’ve used would have lasted 500 miles (ie to the first service on a new bike) without issue !

Cos I now run a 920 and a 1007 I have no option but to use copper head gaskets. These don’t require any re-torquing, they’re MUCH more stable, which is useful when trying to be precise about squish band clearances etc.

'79 onwards T140s used composite head gaskets. Triumph service bulletin 9-79 from January 1979 specifies 'overtightening' the head bolts by a couple of ft/lbs on initial assembly, then resetting them after 500m, presumably at the 'first service'.