79965 Mercury SCREW

Valve Lash, Valve Bridge, Injector Timing & Synchronization
Be sure the starting motors are disabled and engine cannot be started while this maintenance is being performed. This warning is very important when the engine is equipped with an automatic start-stop system.
Before operating barring device for turning the crankshaft, operate the prelube pump to ensure correct prelube procedure. DO NOT crank the engine before prelube, especially after this maintenance procedure, to prevent damage to the crankshaft bearings.The lube oil can drain out from between the crankshaft and engine bearings if the engine has not been run for a period of time. Damage can result if the crankshaft is rotated on dry bearing surfaces.DO NOT use the air or electric starters to rotate the engine. If the engine is rotated too fast, oil cannot flow through the openings in the cylinder head fast enough to prevent damage to the combustion seal.
Check/Adjust
All valve lash adjustments after the Initial 3 Month inspection interval are to be performed at Every 6 Months inspection interval. Thoroughly clean the area around the valve mechanism covers to prevent the entry of foreign matter into the top of the cylinder head and valve mechanism.Prelubing the engine is required when the crankshaft is rotated during normal maintenance operations. This includes adjusting valves as well as engine starting. The prelube pump should also be left ON during the time the engine crankshaft is rotated. The intermittent prelube pump should not be operated continuously for extended periods of time. If, during repairs, the intermittent prelube pump has run continuously for a period of three hours or more, it will be necessary to remove any oil that may have collected in the cylinders and/or above the valves.
DO NOT use an impact wrench or pneumatic motor to operate the 1:1 Manual Barring Device.
The manual barring device provides the ability to turn the flywheel and crankshaft. When the barring group gear shaft is engaged, the starting system is disabled. The 50:1 reduction barring group can be operated with an air or electric tool. The tool must be equipped with a cushion clutch and capable of producing the required torque of 6.8 N m (5 lb ft) for engine only or 16.3 N m (12 lb ft) for engine and generator. The flywheel will turn at less than 3 rpm at 700 rpm tool speed.The gear shaft is spring loaded and must be pushed toward the flywheel to engage the pinion with the flywheel ring gear. The barring group handle is used to secure the gear shaft in the engaged or disengaged positions. Rotate the adapter to turn the crankshaft and the crankshaft and flywheel will be locked into the engaged position. To lock the flywheel and crankshaft from turning, tighten guide to a torque of 270 25 N m (200 18 lb ft).
3612 Engine
3616 Engine The crankshaft/camshaft timing must be checked, and a bridge adjustment made before making a valve lash adjustment. When the valve lash (clearance) is checked, an adjustment is NOT necessary if the measurement is within 0.08 mm ( 0.003 in.) of the value given in the chart.If the clearance dimension is not within this tolerance, proceed to the topic Bridge Adjustment, before making a valve lash adjustment.The crankshaft/camshaft timing must be checked and a bridge clearance adjustment made before making a valve adjustment.Refer to the Service Manual for the complete procedure on Valve Lash, Valve Bridge, Injector Timing & Injector Synchronization.Check Crankshaft/Camshaft Timing
Crankshaft Timing Pin.
Camshaft Timing Pin.The crankshaft and camshaft must be synchronized. If the camshaft timing pin cannot be installed, refer to Camshaft Gear Removal in the Service Manual. Do NOT attempt to adjust the valves if the crankshaft and camshaft are not synchronized. Disregard for this can result in engine damage such as bent valves.Refer to the Service Manual for the correct procedure on crankshaft/camshaft timing.
Be sure to adjust the valve bridges before adjusting any valves. Do the procedure for both bridges for each cylinder.
After checking the bridge adjustment for each cylinder, proceed with the valve lash adjustment, if necessary. If inlet bridges require frequent adjustment, the inlet valve lubricator may not be operating, or improperly adjusted. Refer to the Service Manual for the correct procedure on bridge adjustment.Unit Injector Timing
Refer to the information plate on your engine for the correct unit injector fuel timing dimension.
The 6V6170 Setting Group tooling is required for this procedure.The timing dimension of injectors may vary upon engine application. The fuel timing dimension may be found on the information plate located on one of the valve covers. If further assistance is required, contact your Caterpillar dealer.Refer to the Service Manual for the correct procedure on unit injector timing.Injector Synchronization
Before starting engine, refer to the Engine Starting section of this manual to ensure correct prelube procedure. DO NOT crank the engine before prelube, especially after this maintenance procedure, to prevent damage to the crankshaft bearings.
When this maintenance procedure is complete, ensure that the manual barring device is disengaged from the flywheel and the handle is secured to the disengaged position. Refer to the Service Manual for the correct procedure on injector synchronization.