A cross-bolted bearing is a bearing, usually a

crankshaft A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...

main bearing Main may refer to: Geography * Main River (disambiguation) **Most commonly the Main (river) in Germany * Main, Iran, a village in Fars Province *"Spanish Main", the Caribbean coasts of mainland Spanish territories in the 16th and 17th centuries ...

of a

piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...

. Most bearing caps are retained by two bolts, one on each side of the bearing

journal A journal, from the Old French ''journal'' (meaning "daily"), may refer to: *Bullet journal, a method of personal organization *Diary, a record of what happened over the course of a day or other period *Daybook, also known as a general journal, a ...

, and parallel to the cylinder axis (or, on vee engines, parallel to an axis bisecting the vee angle). A cross-bolted bearing has one or more additional bolts, at right-angles to both the cylinder and crankshaft axes. These bolts may be either a single through bolt passing through the crankcase from one side to the other, or else two blind bolts threaded into the bearing cap from each side. Cross-bolting has two advantages: it couples the two sides of the

crankcase In a piston engine, the crankcase is the housing that surrounds the crankshaft. In most modern engines, the crankcase is integrated into the engine block. Two-stroke engines typically use a crankcase-compression design, resulting in the fuel/a ...

together, making it stiffer overall and less prone to twisting. Secondly it helps to hold the bearing cap down against the downward force from the piston. This second advantage is usually only possible with blind bolts, as the

dowel A dowel is a cylindrical rod, usually made of wood, plastic, or metal. In its original manufactured form, a dowel is called a ''dowel rod''. Dowel rods are often cut into short lengths called dowel pins. Dowels are commonly used as structural ...

effect of a through bolt is less effective.

References

Engine components Engine technology Bearings (mechanical) Threaded fasteners {{automotive-tech-stub

See also

References