Lister diesel engines are likely the most reliable diesel engines ever made. They are 1, 2, and 3 cylinder LOW RPM engines made in England. They are extremely well balanced and extremely heavy. Many of them are in South America and other third world countries running 24/7 powering generators for 20 years straight, stopping only to have their oil changed.
Unfortunately they stopped making them in 1965, so the good Listers can only be had used. An Indian company makes cheap, unbalanced knock-offs called Listeroids, but they require a lot of work to get them up to the standards of an old Lister.
This is a new Listeroid two cylinder.
This is an old Lister single cylinder.