887906A 1 Mercruiser GEAR SET, (29/27)

Allow the engine to cool for at least 20 minutes before you perform a valve lash adjustment.Note: Do not reuse the valve cover Press-in-Place (PIP) seals.Specifications
Table 1
Valve Lash Setting: Engine Stopped and Cold
Valves Gauge Dimension
Inlet 0.80 0.08 mm (0.031 0.003 inch)
Exhaust 1.30 0.08 mm (0.051 0.003 inch) Introduction
Use this procedure for adjusting the valve lash on C175 diesel engines.Required Tools
Table 2
Required Tools
Part Number Part Name Qty
386-3239 Wrench Set (Allen) 1
458-3600 Torque Wrench 1
482-7519 Engine Tool Group(1). 1
(1) The engine tool group is used with "Valve Lash Check and Adjust (Feeler Gage)"Channel 1 Video
Video demonstration on valve lash adjustment is available through Cat™ Channel 1, refer to Table 3 for specific URL and media number.
Table 3
Channel 1 Video
Media Number: CATU0132
Title: C175 Valve Adjustment
Channel 1 URL: https://channel1.videonitch.com/LearningPrograms/Pass/1283 Valve Lash Adjust Preparation
Ensure that the number 1 piston is at the top center position. Refer to Testing and Adjusting, "Finding the Top Center Position for the No. 1 Piston".
The number 1 piston should be at the top center position of the correct stroke. Perform adjustments to the valves according to the chart: Refer to Testing and Adjusting, "Crankshaft Positions for Valve Lash Setting".Valve Lash Check and Adjust (Dial Indicator)
Note: Ensure that you are performing this procedure on a cold engine.Note: Valve lash is measured at the top of wear seat for the intake valves and the exhaust valves. All the clearance measurements and the adjustments must be made with the engine stopped. Ensure that the valves are fully closed.
Illustration 1 g01972533
Installation of the dial indicator
(1) Dial indicator
(2) Exhaust rocker arm
(3) Inlet rocker arm
(4) Adjuster assemblies
Install the dial indicator onto the appropriate arm assembly:
Attach the magnetic base for the dial indicator to a machined surface on the cylinder head of the engine. Ensure that the base is securely fastened to the surface.
Adjust the holding rods so that the dial indicator probe is on the flat portion of the top of the rocker arm wear seat.Refer to Illustration 1.
Firmly tap the rocker arm at the top of the adjustment screw with a soft mallet. The tapping will ensure that the lifter roller seats against the base circle of the camshaft lobe.
Zero the dial indicator.
Pivot the rocker arm on the rocker shaft. The valve lash is the total movement that is indicated by the dial indicator as the rocker arm pivots on the rocker shaft.
Adjust the valve lash on the appropriate valves:
Loosen the adjustment locknut.
Turn the adjuster to obtain the appropriate reading for the valve lash that is measured on the dial indicator.
Tighten the adjustment locknut. Do not allow the adjustment screw to turn while you are tightening the adjustment locknut.Torque for adjustment locknut ... 120 15 N m (90 11 lb ft)
Recheck the valve lash after tightening the adjustment locknut.Valve Lash Check and Adjust (Feeler Gage)
Note: Ensure that you are performing this procedure on a cold engine.Note: Valve lash is measured at the top of wear seat for the intake valves and the exhaust valves. All the clearance measurements and the adjustments must be made with the engine stopped. Ensure that the valves are fully closed.
Tap each rocker arm on the top of the adjustment screw before making any adjustments. Use a soft hammer. Make sure that the lifter roller is seated against the base circle of the camshaft.
Illustration 2 g03862628
(1) Nominal lash
(2) NO/GO
(3) GO
Insert the GO/NO GO side of the tooling between the bridge and the rocker arm foot. Use the blue feeler gage labeled "0.8 INTAKE/RIGHT" for the intake valves. Use the red feeler gage labeled "1.3 EXHAUST/LEFT" for the exhaust valves. The portion of the gage labeled GO (3) should fit between this gap. The portion of the gage labeled NO GO (2) should not fit between this gap.If valve lash is found to be too tight ("GO" gage will not fit or too loose "NO GO" gage will fit), the valve lash needs adjusted.Note: A dial indicator could be used for valves set too tightly to document any valve recession. Refer to the Tool Operating Manual, NEHS0710 for more tooling that can help determine if recession is occurring.
Adjust the valve lash on the appropriate valves:
Loosen the adjustment locknut.
Insert nominal lash (1) of either the intake or exhaust feeler gage between the bridge and the rocker arm foot.
Turn the adjusting screw to close up the gap and tighten the adjustment locknut.Note: Do not allow the adjustment screw to turn while tightening the locknut.Torque adjustment locknut ... 120 15 N m (90 11 lb ft)
Remove the feeler gage. The feeler g