Engine block

Engine blocks often also include elements such as coolant passages and oil galleries.

However, technically, the block of a modern engine (i.e., multiple cylinders integrated with another component) would be classified as a monobloc.

Modern engines, however, often combine many elements into a single component to reduce production costs.

The evolution from separate components to monobloc engine blocks has gradually progressed since the early 20th century.

They are called "wet liners" because their outer sides come in direct contact with the engine's coolant.

The advantages of wet liners are a lower mass, reduced space requirements, and coolant being heated faster from a cold start, reducing start-up fuel consumption and heating the car cabin sooner.

[3]: 120  A rare exception was the Lancia 22½° narrow-angle V12 of 1919, which used a single block casting combining both banks.

[3]: 50–53  The Ford flathead V8 – introduced in 1932 – represented a significant development in the production of affordable V engines.

[4] The communal water jacket of monobloc designs permitted closer spacing between cylinders.

Using steel cylinder liners and bearing shells minimizes the effect of the relative softness of aluminium.

Some engine designs use plasma transferred wire arc thermal spraying, instead of cylinder sleeves, to further reduce weight.

[5] Some modern consumer-grade small engines use a monobloc design where the cylinder head, block, and half of the crankcase share the same casting.

Motorcycles such as the Honda CB750 use a similar layout, with the cylinder block and crankcase integrated with part of the transmission.

Many farm tractor designs integrate the cylinder block, crankcase, transmission, and rear axle into a single unit.