Why are bottom end bolts prone to failure?
Bottom End Bolts, Particularly in Medium Speed Engines, are Prone to Failure under Normal Conditions Connecting rod bottom end bolts keep the two halves of the bottom end bearing together. These bolts are subjected to complex nature of stress as follows:
What can I do to keep bolts from falling off?
While these devices do prevent the nut from falling off the bolt, they generally do not help the joint maintain the specified clamp force. Prevailing torque nuts. Nylon or metal inserts inside a nut (sometimes called a “lock nut”) can add extra friction to prevent loosening.
Is it better to install a bolt down or up?
Coming from one who has been there, it is much easier and safer to install bolt down. Not only is it easier to manipulate and still hang on with one hand, there is also less chance of dropping a bolt on someone below.
What causes a bolt to bend at the bottom?
This results in shear stress in the bolt keeping the two parts together. Bending Stress: Bending stress of a fluctuating nature also takes place while the bottom end is distorting. During the power stroke, the bolt bends outward and during the exhaust stroke the bolt tends to bend inward.
While these devices do prevent the nut from falling off the bolt, they generally do not help the joint maintain the specified clamp force. Prevailing torque nuts. Nylon or metal inserts inside a nut (sometimes called a “lock nut”) can add extra friction to prevent loosening.
What happens when you tighten a nut on a bolt?
In a bolted joint, tightening the nut actually stretches the bolt a small amount, like pulling on a stiff spring. This stretching, or tension, results in an opposing clamp force that holds the two sections of the joint together.
What kind of nuts are used to prevent bolts from loosening?
According to an article in Fastener + Fixing, the idea of using two nuts, a thick one and a thinner one (called a jammer nut), has been used for over 150 years to prevent loosening of bolted joints. A modern application is a system using two nuts each having different sized threads which advance at different rates on a dual-threaded bolt.
What kind of washer should I use to prevent bolts from loosening?
Conical, or Belleville washers, are cup-shaped washers that perform little better than spring washers in vibration tests. Several types of locking washers have been developed, with flutings, ribs or teeth that dig into the surface of the joint during the tightening process, in order to prevent loosening.