First of all, in the improvement of battle tanks, modernization is being carried out - a tank engine. Iran is one of the striking examples of this. By the way, in Iran, B-84 engines began to be installed on English-made Chieftain tanks. The V-84 engine is designed for installation on the T-72 tank.
Chieftain was supplied to Iran by Great Britain even before the 1979 revolution, more than 800 units were purchased in total. They were actively used during the war against Saddam's Iraq, which committed aggression in 1980.
A detailed description of the B-84 tank engine can be found by clicking on the link and get acquainted with other modifications of the V-84 tank engine (V-84M, V-84MB1, V-84-1, V-84A)..