Inline models included two, three, and four cylinders, and the V-types six and eight cylinders.
History
The Series 53 was introduced in 1957; in 1961, the 4-53 and 6V-53 were introduced as options for the 1962 model yearChevrolet-branded medium and heavy duty trucks.[1]:64
Production of Series 53 engines ended in the 1990s along with other two-stroke Detroit Diesel designs, as tightening emissions regulations could not be met with their design.[2]
Design
SP4 Stanley Taylor works on a 6V-53 removed from a M113 at Thủ Đức Water Treatment Plant (1968).
Bore and stroke are the same across all units, at 3+7⁄8in ×4+1⁄2in (98mm ×114mm). These engines use a single camshaft per cylinder bank, paired with a balancing shaft for inline engines, or a second camshaft for the other cylinder bank in vee-block engines. The flywheel drives either one camshaft or the balancing shaft via an idler gear, depending on the specific engine configuration.
Because the Series 53 engines are equipped with a blower which provides relatively little additional intake air pressure, in common with most Detroit Diesel two-cycle engines, they are designated as "naturally aspirated" according to SAE. However, turbocharged variants of the Series 53 exist.
Combustion cycle
Two-stroke diesel uniflow engine animation
In common with similar, contemporaneous two-stroke diesel engines, including the Detroit Diesel Series 71 and EMD 567, the Series 53 does not use crankcase aspiration and cannot naturally draw in combustion air; the Series 53 engines are fitted with a gear-driven Roots blower mounted to the exterior of the engine, which is inherently necessary to charge the cylinders with air for combustion. The air intake ports are through passages bored into the sides of the cylinder sleeves, rather than in the cylinder head.[3]:4
Intake air is discharged from the blower into an air chamber in the cylinder block; when the intake ports are uncovered by the downward stroke of the piston, the air from the air chamber enters the combustion chamber. These intake ports are angled to impart a swirling motion to the intake air. As the piston continues to travel upward, the air intake ports are covered by the side of the piston and the air trapped in the cylinder is compressed and heated.[3]:4,17
Unit fuel injection is employed, one injector per cylinder; each unit injector is responsible for metering the fuel, pressurizing it, and atomizing it when it is injected into the cylinder. No high fuel pressure exists outside of the injector body.[3]:13 The atomized fuel combusts when is injected into the heated, compressed air in the cylinder, creating the power stroke and pushing the piston downward.[3]:4 The injectors are cycled from the same camshaft responsible for opening the exhaust valves.
Shortly after the combustion (power) stroke, the camshaft opens pushrod-operated poppet valves in the cylinder head(s) to allow engine exhaust to escape, through either two or four valves per cylinder.[3]:4 As the piston continues downward, it uncovers the air intake ports again, which helps to displace exhaust gases. This is an example of uniflow scavenging; since the intake air enters at slightly greater than atmospheric pressure, the blower also assists in scavenging spent combustion gasses at the end of the power stroke. When scavenging is complete, the exhaust valves are closed and air continues to be taken in to the cylinder until the intake ports are covered again by the upward motion of the piston.[3]:4,17
Basic arrangement
Most Series 53 engines were "symmetrical," meaning that the blower, exhaust, water manifold, starter, and other components could be mounted on either side of the basic block to fit a particular application. In addition, the engines were designed to run with the crankshaft turning either clockwise or counter-clockwise, called "Left Hand" or "Right Hand" rotation engines, respectively, as viewed from the flywheel side of the engine.
Viewed from the flywheel side of the engine, inline engines could be classified into one of eight basic arrangements, depending on the direction of rotation and location of the blower and exhaust manifold. Similarly, vee-block engines could be classified into one of four basic arrangements, depending on the direction of rotation and the location of the starter and oil cooler.
1234Position of the exhaust manifold either on the (L)eft or (R)ight side, viewed from the flywheel side of the engine.
1234Position of the blower either on the (L)eft or (R)ight side, viewed from the flywheel side of the engine. The blower is driven either by the balance shaft (B) or camshaft (C); the governor is driven by the opposite shaft, so for example, when the blower is driven by the balance shaft, the governor is driven by the camshaft.
1234The idler is driven directly by the flywheel, and in turn, for inline engines, drives either the balance shaft (B) or camshaft (C). The balance shaft and camshaft are meshed together so that turning one will turn the other.
12The idler is driven directly by the flywheel, and in turn, for vee engines, drives either the (L)eft or (R)ight bank camshaft. The two camshafts are meshed together so that turning one will turn the other.
Nomenclature
The first number refers to the number of cylinders in the engine, followed by a hyphen or "V", indicating inline or vee cylinder block arrangements, respectively, then 53 for the Series designation, referring the nominal swept displacement per cylinder in cubic inches, rounding from 53.07cuin (0.9L) per cylinder.
The basic engine code does not have a model suffix identifier: for example, 4-53 is an inline four engine. When the model number includes a suffix, it denotes additional features.
The engine model code is stamped on the cylinder block, consisting of an eight-digit code which provides additional information on the number of cylinders and basic arrangement:[3]:9
For inline engines, a value ending in an odd digit means the starter is opposite the blower; an even digit means the starter and blower are on the same side.
Applications
The 6V53 is most famously used with the M113 armored personnel carrier, starting with the M113A1 variant. The turbocharged version, 6V53T, is used in the M113A3 variant and MIM-72 Chaparral, which uses the M113 chassis. Two marinized 6V53s also were used to power the United States Coast Guard 44-foot motor lifeboats.
Variants
Cylinders are numbered sequentially starting from the front of the engine.[4]:9 The most common Series 53 engines include the 3-53, 4-53, and 6V-53, according to production records from the 1970s and 1980s.[5]
The firing order of the 2-53 (right-hand rotation) is 1-2.[4]:9
3-53
Naturally aspirated 3-53 variants (model 5033-7000) had peak output ratings of 101hp (75kW) at 2800RPM (gross) and 205lb⋅ft (278N⋅m) at 1800RPM, with an 21:1 compression ratio, using N50 injectors.[6] The firing order of the 3-53 is 1-2-3 (left hand) and 1-3-2 (right hand).[4]:9
Turbocharged 3-53T variants (model 5033-8300) had peak output ratings of 131hp (98kW) at 2500RPM (gross) and 312lb⋅ft (423N⋅m) at 1600RPM, with an 18.7:1 compression ratio, using N65 injectors.[7]
4-53
Naturally aspirated 4-53 variants (model 5043-7000) had peak output ratings of 140hp (100kW) at 2800RPM (gross) and 282lb⋅ft (382N⋅m) at 1800RPM, with an 21:1 compression ratio, using N50 injectors.[6] With S45 injectors and the four-valve cylinder head (model 5043-7000), peak output ratings dropped slightly to 130hp (97kW) at 2800RPM (gross) and 270lb⋅ft (370N⋅m) at 1800RPM. The base model (with a two-valve cylinder head and reduced compression to 17:1, model 5043-5101 and -7101) had peak output ratings of 108hp (81kW) at 2200RPM (gross) and 263lb⋅ft (357N⋅m) at 1500RPM[9] The firing order of the 4-53 is 1-2-4-3 (left hand) and 1-3-4-2 (right hand).[4]:9
Turbocharged 4-53T variants (model 5047-5340) had peak output ratings of 170hp (130kW) at 2500RPM (gross) and 402lb⋅ft (545N⋅m) at 1800RPM, with an 18.7:1 compression ratio, using 5A60 injectors.[10] Off-highway 4-53T variants (model 5043-8301) had peak output ratings of 175hp (130kW) at 2500RPM (gross) and 420lb⋅ft (570N⋅m) at 1800RPM, with an 18.7:1 compression ratio, using N65 injectors.[7]
Vee
Engines with cylinder blocks arranged in a vee share the corresponding inline engine cylinder heads; for instance, a 6V-53 uses two 3-53 cylinder heads.[4]:6
6V-53
Naturally aspirated 6V-53 variants (model 5063-7000) had peak output ratings of 216hp (161kW) at 2800RPM (gross) and 445lb⋅ft (603N⋅m) at 1500RPM, with an 21:1 compression ratio, using N50 injectors.[6] The firing order of the 6V-53 is 1L-1R-2L-2R-3L-3R (left hand) and 1L-3R-3L-2R-2L-1R (right hand).[4]:9 The 6V-53 was available with either a cast iron or aluminum cylinder block.[4]:§1.1,1
Turbocharged off-highway 6V-53T variants (model 5063-5300) had peak output ratings of 233hp (174kW) at 2500RPM (gross) and 568lb⋅ft (770N⋅m) at 1800RPM, with an 18.7:1 compression ratio, using 5A55 injectors.[7]
8V-53
The firing order of the 8V-53 is 1L-3R-3L-4R-4L-2R-2L-1R (right hand).[4]:9
Horsepower: 215-320 @ 2800 rpm
Torque: 500-600 lbf-ft @ 1,600 rpm
12V-53
The 12V-53 is a low-production / prototype engine consisting of two coupled 6V-53 engines; fewer than 20 were estimated to have been built, mostly for marine service in generator sets. One of the 6V-53 engines was a left-hand rotation and the other was right-hand rotation; they were coupled at their flywheels.[12]
