Titaniumn Studs

[madman]

I am trying to build a Engine Block and also wanted to use good studs. I am thinking of titaniumn material for its zero stretch properties. Would this be as good as other materials? Like A-2 or Stainless Steel? Also for threading it would a thread roller produce a stronger thread than a die or single point threadiong operation > I am building a Drag Bike engine and wanted something very strong. Thanx Guys

[Orrin]

Stretch is not bad. Stretch can be good. It keeps tension on things.

Orrin

[MickeyD]

The last time that I changed the head gasket on a car you torqued the bolts by snugging them up and then turning something like another half a turn, and this was the procedure from the manufacturer. You actually want the bolts to stretch and apply tension.

[andy_b]

the studs must expand at the same rate (or close) to the rest of the engine. otherwise the engine will expand, the studs won't, and they'll either snap or pull the threads out of the block.

andy b.

[quadrod]

Auto manufactures use what is called a plastic region bolt. They are designed to be torqued so that the bolt is in the middle of it stretch ( zone ? ). On Toyota's you torque to say 20 ft lbs and the tighten an additional 90 degrees and then another additional 90 degrees. This way the bolt can keep a uniform torque on the head gasket weather the engine is hot or cold.

[lakeside53]

Even tricker on Subaru's (and some others) - torque down+angle of rotation, then release a specified amount....

[hitnmiss]

"I am thinking of titaniumn material for its zero stretch properties."


Actually Titanium is very stretchy. It's modulus is about half of steel.

It's can have good yield strength but not stiffness.

[EVguru]

Auto manufactures use what is called a plastic region bolt. They are designed to be torqued so that the bolt is in the middle of it stretch ( zone ? ). On Toyota's you torque to say 20 ft lbs and the tighten an additional 90 degrees and then another additional 90 degrees. This way the bolt can keep a uniform torque on the head gasket weather the engine is hot or cold.

Close.

What matters is the tension in the bolts (and therefore gasket clamping pressure). Torque on a fastener is a pretty poor indication of tension; Any oil, dirt, rust, dings, etc. are all going to change how much torque is required for a given tension (some head bolts were specified with an 'oiled' torque).

Using 'yield' bolts is a much more reliable way of setting the tension.


P.S. How do you get torque on a gasket?

[Langanobob]

"I am thinking of titaniumn material for its zero stretch properties."


Actually Titanium is very stretchy. It's modulus is about half of steel.

It's can have good yield strength but not stiffness.

Yes, that's what I recall, that it stretches a lot more than steel. I don't know much about drag bike engines other than they produce an amazing amount of power for their size for a short time period. Is the combustion pressure that great that head bolts tend to break? I'm having a hard time visualizing that a good grade of properly heat treated steel wouldn't be good enough without the potential complications and expense of titanium. But then it's conjecture since I'm not a drag bike engine builder.

[Mike P]

Madman,

Take a look at the ARP website and catalog. A HUGE amount of useful info from the source for motorsports fasteners.

www.arp-bolts.com

http://www.arp-bolts.com/Catalog/Catalog.html

They've got a whole line of head studs for cars, but no motorcycles listed. You might give them a call.