1493 Force HEAD SCREW. 1/4 - 20 X 5/8

Air Inlet System
The function of the air inlet system is to supply an adequate amount of clean, dry, low temperature air to the engine.Caterpillar offers air cleaner systems with their 3176B Industrial engine offerings. These are sized to the CFM requirements for a specific power and speed rating. The following is offered where an alternate OEM supplied system is chosen.The pressure drop restriction across an adequately sized air cleaner will be 1.5 kPa (6 inches of H2O) when clean. System inlet air piping may add an additional 0.75 kPa (3 inches of H2O) restriction. Thus, this system will have an initial 2.2 kPa (9 inches of H2O) overall system restriction when clean, and is an important indicator for air cleaner element service life. Dirty element change interval occurs when 6.2 kPa (25 inches of H2O) restriction occurs. Higher inlet system restrictions caused by either an undersized air cleaner or too restrictive air cleaner piping will result in foreshortened cleaner change intervals.Maximum recommended clean air induction system restriction is 3.7 kPa (15 inches of H2O).Maximum dirty air cleaner restriction 6.2 kPa (25 inches of H2O).Service indicators are vacuum sensing devices which tell the operator when air cleaner restriction has reached the service or change element operating interval.Air Cleaners
Two stage air cleaners are recommended for most industrial applications. This offers additional service life in dirty and dusty environments. The design incorporates an additional secondary element which remains undisturbed during primary element change periods. Dirt retained within the air cleaner housing or which may be bumped off the primary element during filter change is trapped by the secondary element at diesel engine restart.Oil Bath Air Cleaners
Oil bath air cleaners are not recommended for diesel engine operation. They are sometimes called for in older specifications. Take exception, and rely on dry type air cleaners. Oil bath cleaners are less efficient, operate poorly or not at all in cold weather environments, become ineffective when oil level diminishes, have an efficiency level of 95 percent at maximum, and can cause oil carry over resulting from overfilling or increased inlet air flow.Inlet System
Shielded against direct entrance of rain or snow. Common practice is to provide a rain cap or pre-cleaner.Both pre-cleaners and pre-screeners are used in very dirty environments to ward off agricultural chaff, rock crusher silicon laden air, or any damaging airborne contaminant heavy enough to be removed by swirl type ejection prior to reaching the actual air cleaner filtration element.Several pre-cleaner systems are available on the OEM market. One such system has been selected by Caterpillar as an air pre-cleaner option for Caterpillar construction machinery. This is known as the "Sy-Klone" pre-cleaner. It is available to meet a variety of CFM inlet air requirements and can be adapted to Caterpillar industrial engines.Inlet air piping should be located to ingest the cleanest coolest ambient air possible. Exhaust stack location should not contribute to "recirculation" of exhausted air to the clean air inlet pick up point. Pipe diameter should be as large as the turbocharger air inlet pipe.Avoid wire reinforced flexible hose as inlet piping. This is susceptible to damage from abrasion, abuse, and is very difficult to seal effectively at the hose clamping points. Avoid plastic tubing of any type. Plastic tubing will lose much of its physical properties when subjected to underhood temperatures which can reach 149°C (300°F).Bracing or supports are required if an unsupported air cleaner assembly exceeds 27 N m (20 lb ft) bending moment at the turbocharger inlet pipe casting. Unsupported weight at clamp type joints should not exceed 1.4 Kg (3 lb).A straight pipe section before turbocharger inlet of two to three times pipe diameter is desired to assure that air is flowing in a straight uniform direction as it enters the turbocharger compressor.Air To Air Aftercooler (ATAAC or Charge Air Cooling)
Air to air aftercooling improves fuel consumption and reduces exhaust gas emissions to meet current and future governmental regulations. Its function is to reduce inlet manifold air temperature as much as possible within the normal working range of the machine. Each OEM machine will have unique installation requirements to accommodate an ATAAC system.Reputable radiator system suppliers offer a variety of ATAAC core systems. Three types are commonly used. One is the independent core mounted in front of a regular engine radiator core. A second version incorporates an integral ATAAC core built into the top of a regular radiator section. This dual core arrangement usually has a cross flow engine coolant core. The top 1/3 of the core frontal area is occupied by the ATAAC core, with the remaining 2/3 dedicated to the engine cooling system. A third variation is a side by side arrangement. If the OEM product has sufficient frontal area to accommodate these latter designs, it can simplify ATAAC core plumbing and mounting.An ATAAC core should guarantee minimal charge air leakage. This can be tested by pressurizing the core to 207 kPa (30 psi). It should hold this pressure and not exceed a 28 kPa (4 psi) pressure drop within 15 seconds.Consult the Technical Marketing Information Data or Engine Data sheet for specific BTU heat rejection which must be rejected for a given 3176 horsepower rating.As a rule of thumb, conservative ATAAC heat rejection calculations can be approximated by multiplying rated engine horsepower times 9 BTU/min. Thus, a 365 hp, 3176B engine, would need an ATAAC core capable of rejecting about 3285 BTU/min.Generally, ATAAC core air ducting is made of aluminized steel or aluminum pipe material. It can be from 76 mm (3.0 in) to 114 mm (4.5 in) in diameter. Typically, it will be no smaller than the turbocharger compressor outlet duct. The key element in both air core ducting and ATAAC core selection is to assure the total charge air pressure drop does not exceed 12.5 kPa (3.7 inches of Hg). This is measured from turbocharger outlet elbow P1 to P2 air inlet manifold. (See accompanying Charge Air System schematic).Duct connections are, typically, heat resistant silicon hump type hoses. They are capable to supply