Selfimposed challenge - Quick Engine Lineup

[Kubboz]

These engines are not perfect. They are not even optimal. But there is one outstanding thing about them - The entire lineup was made in 5 minutes.

There are 5 engines:
A12, A16, A20 - your standard engines, having 1.2, 1.6 and 2.0 liters of capacity, respectively
A16S, A20S - performancey variants of the A16 and A20 respectively