This is a Maybach HL 230 V12 petrol engine used in German Tigers and Panthers during the Second World War. No, German tanks were not powered diesel engines as is often thought.
This particular engine is out of a Tiger II.
The Maybach HL 230 is a 23 litre (1,400 cu in) V12 that produces 700 hp, and an enormous 1,850 Nm (1,364 ft lbs) of torque at 2,100 rpm.
The HL 230 was an upgrade over the 600 hp HL 210, which powered the first 250 Tiger Is. The 210 had an aluminium block and a 21 litre displacement, and suffered from reliability issues. To make more power, the engine block was changed to cast iron, and displacement increased to 23 liters, along with other changes, resulting in the HL 230.