Triumph Herald 1200 engine and Spitfire 1300 engine cylinder head nuts torque?

[jagnut66]

Hi, 

Thought I might as well as about both engines whilst I was at it.........

In my Herald manual it states that the cylinder head nut torque setting should be between 42 to 46 lb / ft, so which do members recommend from their experience?

I also have a (ex-Spitfire) 1300 engine sat in the wings, should I need it, what should the cylinder head nuts be torqued to on that engine?

Many thanks,

Mike.

[Pete Lewis]

all torques have a tolerance  hence the range 42 to 46lbft   aim for in the middle 

studs and nuts with the stick of the nut on its washer and head face means these are a  pretty crude science 

to get that torque on a 3/8unf stud you must use high tensile nuts and hard washers  , mini spares do a cheap and high quality washer faced nuts that many use 

if you look at your old washers theres a high chance the nut has bruised and deformed the face this looses torque and head clamping , the heads pant about a lot in use and 

any drop in clamping can lead to gasket failure  quite easily /quickly 

so good washers and nuts are very important 

 

Pete

[jagnut66]

8 hours ago, Pete Lewis said:

aim for in the middle 

Thanks Pete, there is a setting on my torque wrench of 44.3 ft/lbs (normally you add sub-divisions to achieve the correct torque) which would seem to fit with what you advise.

Does someone know the setting for the 1300?

Best wishes,

Mike.

[Colin Lindsay]

I think they're all the same across the range at about 45 (the Spitfire 1500 is higher).

[jagnut66]

Thanks all.

1 division on my torque wrench = 0.74 ft lbs, therefore I have made a note to set it to 44.3 + 1 division = 45.04 ft lbs, when tightening the cylinder head nuts.

Best wishes,

Mike.

[Sparky_Spit]

In the Haynes manual the torque figure given for 1147 and 1296 engines is 45lb/ft and for 1500 engines it is 46lb/ft.

This seems to be pretty specific but makes me wonder whether that extra 1lb/ft for the 1500 is actually correct and worthwhile? 

What does the proper workshop manual say? I don't have one to hand; can anyone check please? 

[NonMember]

9 minutes ago, Sparky_Spit said:

What does the proper workshop manual say? 

The official WSM for the Herald / Vitesse 1600 / Spitfire 1-3 gives the head nut torque as "42-46 lbft". I don't have a proper one that covers the 1500.

[Colin Lindsay]

I was reading some American Triumph sites recently and where the WSM stated 44 - 46 they were all advocating torquing up to 60 or even 80. Fine and dandy if your studs are up to it but I've stripped threads before going very slightly over the WSM recommendations. One of them was even recommending suing Haynes as he torqued to 45 and had engine problems. It's all at your own risk, I wouldn't exceed the book until I was sure of what I was doing, but it's interesting reading.

 

https://www.triumphexp.com/forum/spitfire-and-gt6-forum.8/cylinder-head-torque-spec.852513/

https://www.mgexp.com/forum/mg-midget-forum.3/head-bolt-torque.2194013/

[DanMi]

Some are talking 6 cylinder, on which the mk2 engines had bigger studs 7/16 I think as opposed to the 3/8 for the 4 cylinder and early 6, so they have higher torque settings of 65-70. 1500 is the same as 1200 though Haynes quote 45 for the 1200/1300 and 46 for the 1500.

[Colin Lindsay]

49 minutes ago, DanMi said:

Some are talking 6 cylinder, on which the mk2 engines had bigger studs 7/16 I think as opposed to the 3/8 for the 4 cylinder and early 6, so they have higher torque settings of 65-70. 1500 is the same as 1200 though Haynes quote 45 for the 1200/1300 and 46 for the 1500.

Some are, so ignore those if you will, but the 1500 owners posting are talking about going to 60. The second link is the 1500 engine, they're also advocating torquing as high as 60. To quote: "Send a bill for your time and materials to the genius's at Haynes. 46 inch/pounds - sheesh."

I'll stick with the WSM of 45, otherwise I'll be sending the aforementioned bill to those guys on that forum...

[Pete Lewis]

apart from over torque  you need some pretty good nuts to achieve the   wsm specified   42/46  lbft we have covered hard washers and mini head  flanged  nuts 

one thing that overtorque can do is pull the block and wreck the engine     dont do it   

stick to  the  Torque  Triumph specified  and it works 

there are only two  Triumph based  specifications for these cars 

3/8 x 24 UNF   all 4 cyl and 1600 and  MK1 2 ltr   42/46lbft

7/16" x 24 UNF       all mk2  6 cylinder  2 ltr  and 2500   65/70 lbft 

Pete

 

[PeteH]

Torque Figures are dependent upon the actual grade of steel used for the Fasteners.

Eg; 35T/f/"sq  = 14.68Lb/ft.    50T/f"sq  = 37.9Lb/ft   55Tf/"sq  =  40.9Lb/ft  This for 3/8UNF.

which assuming a high grade steel for O/E studs would indicate the 42/45Lb/ft in the Manual as Ball park. Anything (Much) higher would risk taking the steel beyond the elastic limit.

Pete

 

 

[Pete Lewis]

hence why the triumph nuts are toughend   ( normally black oiled finish )       any std 3/8  nut will strip at around 35   or less   

Pete

[Sparky_Spit]

Ok thanks all for clarification via the official WSM. My son and I have been using the MInispares flanged nuts for years now, on 3 different MInis and 3 different 4 pot Triumph engines and have never had an issue with them; they really are very good.

[Pete Lewis]

thats good 

Pete