High Tensile Cylinder Head Studs

[Mr. V]

My 1973 1275 Midget engine has dimple-ended cylinder head studs, and nuts with thick washers. Does this mean that the studs are high tensile and the nuts aren't. Would I profit from buying a set of flanged nuts?

[Andmurph]

Hi, my 1972 1275 Midget has the same. I changed the head gasket last year and reused the studs and bolts after a thorough clean. 2000+ spirited miles later and they’re doing fine.
It’s important to clean the threads in the block as well and if the threads on the studs are damaged at all I would replace them.

[philthehill]

The dimple in the top of the stud indicates that the stud is a high tensile item.
Other indicators that the studs are high tensile are a taper top to the stud and a 'Y' stamped into the top of the stud.
The later flanged nuts should be used with the high tensile studs and they can be torqued to 50lb ft. You will be better off with using the later flanged nuts. https://www.minispares.com/cam4545-head ... inder-head
The early non flanged nuts should not be torqued to 50lb ft. Unless you know the source of the head nuts/head washers you should consider them to be non high tensile and only torque to 42lb ft. Do not lubricate the threads of the studs/nuts. Studs can be screwed hand tight into the block or lightly nipped up. Do not over tighten the stud into the head.
Lightly countersink the top of the block before fitting the studs to eliminate any block pull up around the stud which could restrict the pulling down of the head against the top of the block leading to head gasket failure.
If you have a eleven stud head the front stud should be only torqued to 28lb ft as the top of the head is quite thin in that area and cannot stand a torque of 50lb ft. The front stud was originally a 5/16" bolt.https://www.minispares.com/aeg248-cylin ... t-cooper-s

countersunk studs.jpg (348.39 KiB) Viewed 1215 times

[Mr. V]

Thanks both of you. I've read that the studs should, when reinserted, be done up finger tight. Is this the case?

[philthehill]

As I said above hand (finger) tight or lightly nipped up.
Those studs that encroach into the water jacket may need to have some sealant applied to the stud threads before insertion into the block.

[Mr. V]

Sorry Phil. My mistake.