TR2/3/3A The thread pitch of the cylinder head studs?

[karls59tr]

Does anyone know what it is? I'm ordering new head stud nuts and Summit Racing wants to know.

 

[mctriumph]

New nuts on OLD studs??????????????????
Mad dog

 

[karls59tr]

New nuts on OLD studs??????????????????
Mad dog

Yah I know. I dont want to risk removing the rear studs to replace them with new ones because I think doing so will just make the existing hairline cracks on the block bigger when doing the install. I'm thinking just new nuts will "at least help" to get a better seal on a new head gasket. I saw a father and son team that were doing a rebuild on a TR4 engine and they could not get 3 studs out of the head so they opted to just go with new ARP nuts and it worked for them. I am going to replace the block with a spare one at some point but for now I want to try one more time to get the gasket to seal so I can at least get one more summers driving out of the car before doing a major tear down and block replacement in winter. Do you happen to know what the stud pitch is?

 

[Sarastro]

They are 1/2 UNF, which is 20 threads/inch. You also should be CERTAIN to get grade 8 nuts and washers.

That said, I doubt that new nuts will help. If you can torque the old ones to spec, what's the difference between new and old?

 

[karls59tr]

They are 1/2 UNF, which is 20 threads/inch. You also should be CERTAIN to get grade 8 nuts and washers.

That said, I doubt that new nuts will help. If you can torque the old ones to spec, what's the difference between new and old?

I've heard Grade 8 bolts could crack the block? What grade is the stock nut?

 

[mctriumph]

Sick idea, set the new studs with epoxy in the cracked areas. The force of tightening the stud
will push the epoxy into the cracks. Then you have new studs that can be torqued accurately.
If your block is the problem(?) this can hurt nothing. Metal bonding epoxy will handle the heat just fine.
Chase the threads where the issue is, coat the studs and set them in place.
Mad dog

 

[karls59tr]

Sick idea, set the new studs with epoxy in the cracked areas. The force of tightening the stud
will push the epoxy into the cracks. Then you have new studs that can be torqued accurately.
If your block is the problem(?) this can hurt nothing. Metal bonding epoxy will handle the heat just fine.
Chase the threads where the issue is, coat the studs and set them in place.
Mad dog

That sounds like a plan.

 

[GeneJohnson]

That sounds like a plan.

Unless there is some new epoxy I'm unfamiliar with, many epoxy resins soften and is unusable at boiling point of water, 100C /212F. I wouldn't recommend using it on most anything engine compartment related, particularly the engne.

 

[Sarastro]

I've heard Grade 8 bolts could crack the block? What grade is the stock nut?

That's just not true. Look at ARP hardware, for example; it's actually much stronger than grade 8.

If you work it out, you'll find that the tension in the head stud is actually close to the yield strength of a grade 8 fastener. That's why you MUST buy good hardware, grade 8 or better. Do those cheapo studs made in Indonesia somewhere really meet grade standards? Perhaps, but I wouldn't blithely assume that they do.

 

[mctriumph]

Gene, metal bonding epoxy is good to 300F+. We all hope and pray to keep things cooler than
this at all times, lest bad stuff happens.(catastrophic failure).
Mad dog

 

[CJD]

I have tossed many stock studs because they would not torque to spec. I feel they are right at the edge of being acceptable. Also, the original nuts are taller than available nuts, aren't they? I've never had an issue with stock nuts. Washers should be hardened and ground for flatness.