Torque-to-Yield (TTY) head bolts are used on many late model engines to clamp the cylinder head to the block. They differ from ordinary head bolts in that TTY bolts are designed to stretch slightly when they are tightened down.
What is a TTY head bolt?
A torque to yield fastener (TTY) or stretch bolt is a fastener which is torqued beyond the state of elasticity and therefore undergoes plastic deformation , causing it to become permanently elongated.
Can I use the same cylinder head bolts?
A head bolt should not be reused if the threads are galled or badly damaged . ... Chasing damaged head bolt threads with a die will clean up the threads but also remove material (metal) and undermine the head bolt’s ability to torque down and hold to specs.
What is a cylinder head bolt?
Cylinder-head bolts are the connecting elements between engine block, cylinder-head gasket, and cylinder head . The bolt tightening force is an important factor for the mutual sealing of combustion chamber, lubricant and coolant channels, and the ambient air.
Can you reuse b18 head bolts?
RE: reusing head bolts
Re-used the head bolts, no problems. As long as you don’t over tourqe them you should be fine .
Should you oil head bolts?
As a rule, the threads and underside of the head on most standard automotive head bolts should be lubricated with motor oil before the bolts are installed . The torque values specified by the engine manufacturer are typically based on oiled threads and fasteners – not dry fasteners.
Should you oil TTY bolts?
* TTY bolts are usually installed dry. Do not apply any oil, grease, assembly lube or sealer on the bolt threads . The reason why is because lubricants reduce friction when a bolt is tightened. This actually increases the torque load on the bolt, which may overload and stretch a TTY bolt too far, causing it to break.
When should the cylinder head bolts be replaced?
Bolts are designed to stretch as you torque them into place, and when you remove them, they snap back to their original position. Because of this, many standard head bolts are okay to use more than once, as long as they have not been stretched past their spring back point .
Can ARP head bolts be reused?
Are ARP bolts and studs re-usable? Yes . As long as the fasteners have been installed and torqued correctly, and show no visible signs of damage, they can be re-used. If they show any signs of thread galling or corrosion, they should be replaced.
Why do head bolts break?
Fatigue failure happens when the bolts have not been tightened properly, or have loosened up during its service life. If enough force is acting on the loosened joint during use of the product, bending stresses can weaken the fastener, eventually causing it to fail.
What happens if head bolts are not tight enough?
But even the best head gasket won’t maintain a tight seal if the head bolts have not been properly torqued. ... Another consequence of failing to torque the head bolts properly can be head warpage. Uneven loading created by unevenly tightened head bolts can distort the head.
Do I need to drain oil before removing head?
Re: drain oil to remove heads? The oil does not have to be drained but it is usually a good idea to change the oil after any internal engine repairs. You could drain it first and reuse it possibly. Going “inside the motor won’t be fun because the crankcase has to be split to change the cam or crank.
What happens if you over tighten head bolts?
When you overtorque above 15% of recommended which in this case would be about 95 ft/lbs you basically turn the fastener into a rubber band . Some of the fasteners will stretch and you will have uneven torque. Add heat and pressure and head gasket blows and the head can even warp.
Can you reuse Honda head bolts?
No do not reuse them . Just because other people have done this and had no problems doesn’t mean you should! Most head bolts are torque to yeld bolts. That means that after they are used once to replace them.
Should I put anything on head bolts?
If you use anything, make sure it’s a very light coat. You don’t want the oil running off the bolt and settling in the bottom of the bolt hole. For bolts going into thru-holes, you can put as much lubricant as you want , but for blind holes, you need to be careful not to put too much.
Do you put anything on a head gasket?
Sealant for head gaskets usually have the viscosity of an oil. Gasket Goo, whilst not familiar to me, sounds too thick for a head gasket. Almost all head gaskets I have ever seen DO NOT USE ANY TYPE OF EXTRA SEALANT. I would highly suggest you DO NOT add any separate ANYTHING on the head gasket .
