16081 Mercury NUT, RECTIFIER SCREW

3176 Truck Engines WITHOUT Jacobs Brake
Wiring Harness Adapter (Required)
4P5880 Harness Assembly
When replacing a 2YG 3176 Truck engine with a 7LG 3176 Truck engine a 4P5880 Harness Assembly (adapter) is required to adapt the 40 PIN Deutsch connector on the 7LG engine to the 9 PIN Deutsch connectors on the OEM wiring harness. When replacing a 7LG 3176 Truck engine with a 2YG 3176 Truck engine a 4P5881 Harness Assembly (adapter) is used.Refer to SERVICE MAGAZINE ... May 13, 1991 for a detailed explanation of the 4P5880 and 4P5881 Harness Assembly (adapters) and compatibility with the DDT and ECAP Service Tools.Engine Monitoring Package (Optional on 7LG07500-Up)
If the customer wants the Engine Monitoring Package option, a lamp must be installed in the truck cab.The engine monitoring can be programmed to OFF, , DERATE, or SHUTDOWN through a customer programmable parameter. The lamp is not the same as a Check Engine lamp.Refer to Warning Lamp Wiring Schematic in this instruction.Coolant Level Sensor (Optional on 7LG0500-Up)
A Coolant Level sensor is optional and may be installed in the radiator top tank or shunt tank.A wiring harness must be fabricated to connect the 4 pin Packard connector on the sensor to the OEM (P7) connector.A standard coolant level sensor extension wiring harness can be purchased from an OEM and modified for installation. Modify the extension harness by removing the OEM harness connectors and installing Deutsch sockets.The Deutsch sockets will plug into the proper OEM (P7) connector.Refer to Coolant Level Sensor Wiring Schematic, OEM Coolant Sensor Part Numbers, and OEM Coolant Level Sensor Connector Harness Part Numbers and Harness Lengths in this instruction.The Coolant Level sensor is ENABLED or DISABLED through a customer programmable parameter.3176 Truck Engines Equipped WITH Jacobs Brake
Wiring Harness Adapter (Required)
4P5880 Harness Assembly
When replacing a 2YG 3176 Truck engine with a 7LG 3176 Truck engine a 4P5880 Harness Assembly (adapter) is required to adapt the 40 PIN Deutsch connector on the 7LG engine to the 9 PIN Deutsch connectors on the OEM wiring harness. When replacing a 7LG 3176 Truck engine with a 2YG 3176 Truck engine a 4P5881 Harness Assembly (adapter) is used.Refer to SERVICE MAGAZINE ... May 13, 1991 for a detailed explanation of the 4P5880 and 4P5881 Harness Assembly (adapters) and compatibility with the DDT and ECAP Service Tools.Engine Monitoring Package (Optional on 7LG07500-Up)
If the customer wants the Engine Monitoring Package option, a lamp must be installed in the truck cab.The engine monitoring can be programmed to OFF, , DERATE, or SHUTDOWN through a customer programmable parameter. The lamp is not the same as a Check Engine lamp.Refer to Warning Lamp Wiring Schematic in this instruction.Coolant Level Sensor (Optional on 7LG0500-Up)
A Coolant Level sensor is optional and may be installed in the radiator top tank or shunt tank.A wiring harness must be fabricated to connect the 4 pin Packard connector on the sensor to the OEM (P7) connector.A standard coolant level sensor extension wiring harness can be purchased from an OEM and modified for installation. Modify the extension harness by removing the OEM harness connectors and installing Deutsch sockets.The Deutsch sockets will plug into the proper OEM (P7) connector.Refer to Coolant Level Sensor Wiring Schematic, OEM Coolant Sensor Part Numbers, and Coolant Level Sensor Connector Harness Part Numbers and Harness Lengths in this instruction.The Coolant Level sensor is ENABLED or DISABLED through a customer programmable parameter.Jacobs Housing Assembly Model Number (Required)
The 3176 Truck Engines 7LG7500-Up have an improved design (Model 317C) engine brake.The Model 317C features a new housing assembly, master piston assembly (anti-rotation pin designed out), control valve/spring, Power Lash assembly (clip valve), for improved engine retarding performance and service life.The 3176 Truck Engines 7LG7500-Up requires the Jacobs Model 317C Housing Assembly. The Jacobs Model 317C Housing Assembly is NOT interchangeable with the Jacobs Model 317, 317A or 317B Housing Assemblies that are used on 3176 Truck Engines 2YG1-Up and 7LG1-7499. The Jacobs Brake Housing Model 317B has the same improvements as Model 317C. The Model 317C has a different Slave Piston Lash Setting then Model(s) 317A and 317B. Refer to Application and Adjustment Information in this instruction.
Installation of the WRONG Jacobs Model Housing Assembly on a 3176 Truck Engine may cause engine damage.Refer to Jacobs Application and Adjustment Information in this instruction.
Jacobs Electrical Control Group and Type of Connector (Required)
Jacobs Electrical Control Group
The Jacobs Electronic Control Group for the 2YG 3176 Truck Engines requires a pulse width modulated (PWM) signal from the 3176 engine's ECM.When the 2YG 3176 Truck engine is replaced with a 7LG 3176 Truck engine the Jacobs electronic control Must be replaced with a relay group to operate on a +12 Volt signal from the 3176 engine's ECM.The Jacobs Electrical Control Group for 3176 Truck Engine 7LG1-7499 and 7LG7500-Up is the same basic system, requiring a +12 Volt signal from the 3176 engine's ECM.Refer to Jacobs Relay Group, in this instruction, for individual componets. Componets may be purchased separately or as a group.Type of Connector (Required)
The connector at the Jacobs valve cover spacer is a spade type (design) on 3176 Truck Engines 2YG1-Up and 7LG1-07499.The connector at the Jacobs valve cover spacer is a bullet type on 3176 Truck Engines 7LG7500-Up. A Jacobs 18105 Adapter Harness is available to adapt the spade connector to the new bullet connector.Refer to 18177 Jacobs Spacer Group in this instruction.Refer to Jacobs Electrical Control Groups in this instruction.Reference part number/form number:015851D ... Installation Manual For Models 317 and 317A Engine Brakes18425 ... Installation Manual Addendum For Models 317B and 317C Engine Brakes Correct electrical ground is important. If the Jacobs control ground is questionable, run a green ground (GR) directly to the engine's cylinder head ground stud.Components Needed When Installing a Different Model Year 3176 Truck Engine
Warning Lamp Wiring Schematic
Coolant Level Sensor Wiring Schematic
The sensor common can be connected to Pin 2 OR Pin 6.OEM Coolant Level Sensor Part Number
Ford F1HT-10D968-AAFreightliner RSC 85927C1Kenworth 85927C1Navistar 1673785C92Peterbilt 85927C1Robert Shaw 805BVolvo 8169760OEM Coolant Level Sensor Connector H