The Detroit 53 series consists of two different types of engines:
The IL 53 (inline), is made up of four engine models: 253, 353, 453 and 653
The V53, includes the 4V53 and the 6V53 models
The IL 53 series is mainly identified by the single cylinder head on the top of the engine while the V53 has two separate cylinder heads, one on each side coming out at an angle or a V.
What separates 53 Series engines from other Detroit series engines
When looking at the engines from the rear, you can see that the governor is placed in the rear of the engine on either side - no other Detroit engine has the governor mounted in the rear
When looking at the top of the engine, you can see that the 53 series engines have no water manifolds
The water pumps are mounted to the oil cooler, not the blower
Identifying 71 Series engines
The Detroit 71 series is comprised of:
The IL 71 (inline), with the 271, 371, 471, and 671 models
The V71 engines include the 6V71, 8V71, 12V71, and 16V71
These engines separate themselves from the 53 series mostly by the size of the engine. The 71 series engines can be much larger than the 53 series depending on how many cylinders the engine has.
Differences between 71 Series and 53 Series engines
The 71 series has the governor on the front of the engine instead of the rear
The 71 series engines have water manifolds
The water pumps on the 71 Series are mounted to the blower, not the oil cooler
Looking at the side of the IL 71 Series engine
There are obvious air box covers running along the side of the 71 Series engines. These covers look like small plates and the number of these plates may vary depending on how many cylinders the engine has.
There are 2 types of cylinder heads on the IL 71: a cast iron head which has the connecting bolts along the edge of the cover and the aluminum cylinder head which has the connecting bolts running down the center of the cover.
Looking at the front of the V71 Series engine
The water pump is mounted on the front, left hand side of the engine
The blower is mounted on top of the engine between the cylinder heads
The governor is placed directly in front of the blower, not mounted on the side of the blower
It is easy to tell what size V71 engine you have by counting the number of exhaust ports on either side of the engine. The engine has one exhaust port per cylinder. For example, if there are three exhaust ports on either side of the engine then you have a six cylinder engine, four ports on either side is an 8 cylinder engine, etc.
Identifying 92 Series engines
The Detroit 92 series is made up of the 6V92, 8V92, 12V92 and 16V92 and are strictly V engines. The 92 series and the V71 engines are almost identical in appearance.
Differences between the V71 and V92 Series engines
The top of the block of the V71 is curved when the top of the block of the V92 comes to a point. (This can be seen by standing on the side of the engine and looking directly under the cylinder head
Detroit Diesel V92 block
Detroit Diesel V71 block
The water pump on the V71 series engine is held on by a snap ring when the water pump on the V92 series is held on by a plate that is bolted on, not held on by a snap ring.
Identifying 149 Series engines
The Detroit 149 Series is made up of the 8V149, 12V149, and the 16V149. This series of engines are the largest of any of the Detroit 2 cycle engines. The bare block alone is twice the size of any other block and the mere size of these engines makes them very distinctive from the 53, 71 and 92 Series engines.
Identifying Series 60 engines
The Series 60 is the most used and popular engine of the Detroit 4 cycle engine family. While the 2 cycle Detroit engines are strictly mechanical, the Series 60 4 cycle engine is electronically controlled, making it a much cleaner running engine. Series 60 engines are found in most large trucks that are on the road today.