The 1.6 diesel engine are made by the french group PSA ( Peugeot Citroen ), this engine is located on the Mazda 3 and the new minivam 5 series from MAzda.
Have them on all Peugeot and Citroen models, Volvo C30 and S/V50, Ford Focus and CMAX.
Subaru have the 2.0 diesel boxer, Mitstubishi have the 1.8, 2.0 (VW PD) and the 2.2 Renault.
Peogeut/Citroen have the 1.4,1.6,2.0,2.7
Honda have the 2.2 wonderful smooth engine on the Accord
Toyota have the 1.4,2.0 and 2.2 diesel engine
Kia/Hyundai have several, the latest is the 1.7 diesel
Mercedes have the 1.7,2.0,2.2,3.2 and so on
BMW have the 1.8,2.0,2.5,3.0 and so on
VW group have the 1.2,1.6,2.0,2.7,3.0 and so on
Renault have the 1.5,1.9,2.0,2.2 and 3.0 engine
Mazda 1.6 is well, lets just say its not from madza.
The cam shafts have given tons of troubles on the Mazda 6 models.
One main problem with mazda, Subaru and honda is the price of parts and service.
Toyota is one of the cheapest.
I may have missed some diesel engine, sorry