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Cylinder Head Torque setting for a 250 Jubilee

Submitted by ian_black on Mon, 02/11/2020
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Light Twins

Hi All

I am about to refit my heads to a 1959 Jubilee - can anyone tell me the correct Torque settings for the nuts?

Also, When I removed the heads there were only the centre 4 stud nuts with washers - I presume that all the studs should have washers to spread the load on the nuts?

Regards Ian

Submitted by ulrich_hoffmann on Mon, 02/11/2020

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Ian, the manual says 15 foot pounds.

There should be washers under all the nuts.

Stay safe! Uli

Submitted by peter_holland1 on Tue, 03/11/2020

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Ian,

If you find one of the washers under the cylinder head nuts is very thick - about 2mm, this is the correct washer. You must use these.

Thinner steel washers will not be able to take the load under the small section cylinder head nuts and will become dished. 

The aluminium under the weak washer will get overloaded and squeeze down. The hole in the cylinder head will close and nip the stud. The distortion of the aluminium under the weak washer will take the tension off the cylinder head studs.

Peter

 


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