Advantages of an in-line /straight

Packing cylinders in an engines is the trickiest part. One has to balance the need for power Vs torque while deciding on an engine assembly format. Longer stokes delivers higher torque while shorter strokes are preferred for HP. 

What are the advantages of an in-line/straight engines?

Advantages of an in-line /straight

Let's start from the starting. Engine cylinders can be laid in different formats, however, the most popular ones are in-line/straight or V shape assembly of cylinders in the engine. Other assemblies are Rotaries, Flat/Horizontal/Boxter.

In in-line/straight format all cylinders are laid in a line  beside each other, whereas in V format they assembly forms a V shape. Both formats have their advantages and disadvantages. BMW's prefers an in-line cylinder format even when the nos of cylinders in the engine are 6 or more. In-lines are suited more for RWD as they would create torque issues in FWD. RWD's depicts much better road handling characteristics. Other manufacturers prefer the V format.

Advantages of an in-line/straight

Naturally Balanced as in-line keeps drive-shaft in line forming a perfect match. They don't normally need balancing shafts, unlike the V's. 

Naturally balanced means less vibrations therefore lesser load on bearing which can wear off faster even there is a smallest margin of error in balancing.

In-line engines are smother and have higher top-end (red-line) as all pistons are firing in the same direction.

Preferred when there is a need for high torque to get of the line first. In-line generates higher torque due to long stroke and more rotational mass. 

In-line/straight are cheaper, easier to maintain thanks to easy access under the hood.

Disadvantages of an in-line/straight

In-lines/straight are taller engines as the engine block needs to be fitted under the hood. This would cause aerodynamic and even HP losses.

In-lines are longer engines therefore need a much larger nose, which could cause problem in high bumper to bumper traffic.

In-line engies tend be heavier they need stiff blocks and lots of support. Earlier there used to be cooling issues with this format.