Topic: Identifying HD Studs

[jlapoint]

This winter, Christmas Eve actually I trekked across northern Ohio and Northern Indiana to pick up a 76 750SS I purchased over the phone in one of those impulse buys.  I got it home and started looking and discovered it had electronic ignition, coils, hd valves which led me to discover it was also cammed and had 836 pistons. I pulled the head because I had a leaking base gasket and discover 1+4 pistons had problems with expanded top ring grooves. This led me to buy new pistons and now I am ready to put it back together.  Anyway to my real question? This is my first 750? Is there an easy way (diameter) to identify hd studs. Those installed seem substantial but not having another to compare to I have no way of know if they are origial or not.  Any help..
 Jim

[City Boy]

Good morning.Standard studs will have a reduced diameter between the upper and lower threads.HD studs,at least all that I have ever seen,will be the same diam.,top to bottom.Rock On

[nippon]

Please take a look at the pics.

nippon

[bwaller]

If I could piggyback a question here I'd like to know how often these HD studs can used.

I've had a set in my engine forever but have only been torqued twice. However I recently broke down an engine with some as well but do not know it's history. Is it better to scrap them in case they have seen several torque experiences or is the material hardy enough to be reused without worry?

[nippon]

I guess the material is strong enough,.....only the original studs will stretch.
But there is a member on the board working for APE,....probably he will give you the right answer.

nippon

[Big Jay]

Yep, those photos of the heavy duty ones are ours. Back in the day of racing the 750s the motors came down quite ofter, and no one changed out our studs.

Jay

[lordmoonpie]

Is there never any stretch in HD studs or is there a tolerance we could look for? What's the difference between forged HD and rolled HD?

[754]

not understanding what you mean by Forged..

Rolled threads are the strongest.

[mystic_1]

Rolled threads are produced by turning the part against some rolling dies that press into the metal and deform it to form the threads, as opposed to your more typical die which forms threads by shaving away material.

Here's a couple of pages that describe the process:

Rolled vs Cut Thread Bolts

KEYSTONE THREAD ROLLING PROCESS

Why Thread Rolling Is Better


hth

mystic_1

[eurban]

I would think that the biggest strength gains from the HD studs is related to the material used (Chromoly steel I believe) and their diameter rather than how their threads are created. 

[754]

Strength comes from material & diameter.

Rolled thread will outlast and outperform cut thread.. so yes it does matter..

stock thread are probably rolled, it is quicker, cheaper and (big plus) chipless.

[754]

Mystic.... at least 3 ways to roll,

another is two flat dies moving opposite directions.

[mystic_1]

Figures, there's always more than one way to thread a cat

mystic_1