Detroit V-53 Series Two Stroke Diesel

All 53 series diesels, regardless of displacement, feature a 3.875 inch bore and 4.50 inch stroke. It was offered in 3 cylinder, 4 cylinder, 6 cylinder, 8 cylinder and 12 cylinder configurations. The 8 cylinder version was primarily used in marine applications, although it was much less popular than the marine 8V-71. The 12 cylinder version is extremely rare and was reportedly only produced for 1965 to 1968 model years; it is rumored that under 25 of these engines were placed into service. This likely because the larger 12V-71 was more apt for applications that required an engine in this horsepower range and could manage the spacial restraints of a long, 12 cylinder engine. The 12v-53 produced just over 400 horsepower, where as the 12 cylinder 71 series produced a minimum 450 horsepower and up to 900 horsepower. The "silver 53" series was introduced in 1984. Modifications to the engine family promised better fuel economy, quieter operation, and more horsepower across the board.

The 53 series two stroke diesel was attractive for several reasons, but there are many fallacies surrounding two stroke diesels in general. Unlike a small gasoline two stroke engine, which are familiar to most people, two stroke diesels do not run on a fuel-oil mixture and have an oil filled crankcase like a traditional 4 cycle engine. Although the two cycle Detroit diesels do not have intake valves, they do have traditional camshaft driven exhaust valves. A two cycle diesel experiences a power stroke every two strokes, and the primary benefit is a high horsepower per CID (cubic inch of displacement) ratio. This is a result of the engine cycle's high thermal efficiency. The horsepower-to-weight ratio, however, is relatively low and the Detroit two cycle diesels are relatively heavy. A 159 CID engine, for example, weighs in at nearly 1,000 lbs. For comparison, a fully dressed Cummins 6BT is roughly 975 lbs and displaces 359 cubic inches!

All Detroit 53 series engines use a unit injection system. A unit injector is a fuel injector where injection pressure is created in the injector body itself via a camshaft driven plunger in the injector. In practice, this mechanical system works well, however it can be difficult for an inexperienced mechanic/technician to synchronize the injectors as each bank is controlled by a shared linkage. A significant advantage of two stroke diesel engines in marine applications is there versatility; unlike 4 stroke engines, a two stroke engine design can be operated in clockwise or counterclockwise directions.

Detroit 53 Series Specs