MIL-T-62491 Trucks, Wrecker: 4540 To 40 820 Kilograms 5-Ton To 45-Ton Lifting Capacity, Modified CommercialThis specification covers all commercial, non-tactical wreckers procured for military use. Vehicles procured under this specification are commercial items which are warranted by the manufacturer as specified in acquisition documents.

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MIL-T-62491C

3.4 Chassis components.

3.4.1 Engine. The engine furnished for the specified vehicle class shall be the chassis manufacturer's standard or optional engine for the commercial model truck which meets or exceeds the requirements of this specification.

3.4.1.1 Diesel engine. Unless otherwise specified (see 3.4.1.2), the vehicle shall be equipped with a liquid cooled, compression ignition, two-stroke or four-stroke cycle diesel engine. Engine net power used in performance prediction calculations shall be determined in accordance with SAE J1349. The engine shall demonstrate the performance characteristics specified herein when using diesel fuel conforming to VV-F-800. In addition, when specified (see 6.2), the engine shall operate satisfactorily on grade JP-4 and grade JP-5 fuel conforming to MIL-T-5624 under emergency, short duration conditions and on grade JP-8 fuel conforming to MIL-T-83133 under normal conditions. A power loss when operating on JP-4, JP-5 or JP-8 is acceptable.

* 3.4.1.2 Gasoline engine. When specified (see 6.2), the vehicle shall be equipped with a liquid cooled, internal combustion, four-stroke cycle gasoline engine. The engine furnished shall produce the required vehicle performance when operated on unleaded fuel with a research octane rating of 91, at an engine speed of not more than the manufacturer's recommended operating speed. The engine shall be capable of warranted operation on unleaded fuel when used in accordance with the operator's manual. Engine net power used in performance prediction calculations shall be determined in accordance with SAE J1349. Unless otherwise specified or required by foreign laws, vehicles for overseas use shall be capable of accepting and operating

on leaded gasoline.

* 3.4.1.3 Oil filter. A full flow or combination full flow and bypass oil filter with replaceable element shall be furnished.

3.4.1.4 Governor. Except for class 10 wreckers, an engine governor shall be furnished, set and sealed to limit the engine to the engine manufacturer's maximum recommended operating speed.

* 3.4.1.5 Cooling system. The cooling system shall maintain engine coolant at a temperature below the boiling point with the vehicle loaded and operated at an altitude of 3050 mm

(10,000 feet) above sea level or in an ambient air temperature of not less than 52° Celsius ( C) (125 degrees Fahrenheit ( F)). The coolant system shall include a surge tank or a coolant recovery reservoir of not less than 1.89 liters (L) (two-quart) capacity. On tilt cab models, a radiator servicing access door shall be provided to allow ready verification of coolant level. For cooling system servicing, see 3.4.28.1.