STC Oil Control Valve (Mechanical) ( )

View Installation Instruction Page 1 of 10 STC Oil Control Valve (Mechanical) (006-037) Table of Contents Summary Initial Check Preparatory Steps Remove Clean Install Finishing Steps Summary Record part number and upper and lower shift point values of step timing control valve. Connect 0-300 psi pressure gauge to fitting installed between rocker housing and oil outlet line. Disconnect step timing control fuel pressure sensing line from inlet of cylinder head, and connect to pressure regulator. Connect 0-160 psi pressure gauge to pressure regulator. Connect shop air line to pressure regulator. Adjust pressure regulator for 0 psi. Operate engine at idle and measure oil pressure between step timing control valve and tappets. Step timing control oil delivery system is not functioning properly refer to Procedure 006-045. Slowly increase air pressure until oil pressure drops below 55 kpa [8 psi]. Record pressure at this shift point. Pressure must be 103 kpa [15 psi] minimum. Raise air pressure to at least 103 kpa [15

Page 2 of 10 psi] above shift point, then slowly lower pressure until oil pressure goes above 55 kpa [8 psi]. Record this point. Compare shift point values to those specified for the valve. Remove acorn nut from step timing control valve adjusting screw and loosen locknut. Turn step timing control valve adjusting screw clockwise to raise upper shift point, or counterclockwise to lower the upper shift point. Repeat step timing control shift point check. Repeat calibration and check until shift points are within specifications. Replace valve if it cannot be calibrated to specification. When valve is calibrated, tighten locknut and install acorn nut and tamper-proof wire. Clean valve and surrounding area. Remove fuel pressure sensing line, oil outlet line to tappets, and oil vent line. Remove capscrews, valve, and seal ring. Clean the step timing control oil control valve and the surrounding area before removing it from the engine. Remove the following lines: fuel pressure sensing, oil outlet, oil vent. Clean the outside of the valve and all the removed parts. Dry with compressed air Install new seal ring. Install step timing control valve and tighten capscrews. Connect the lines to the step timing oil control valve. Refer to Procedure 006-068. Upper shift point - Minimum 125 kpa [18 psi]. Upper shift point - Maximum 193 kpa [28 psi]. Lower shift point should not be more than 34 kpa [5 psi] below upper shift point. See detail. Refer to Procedure 006-068 Torque: 41 N m [30 ft-lb].

Page 3 of 10 Initial Check Record the part number of the step timing control valve from the data tag on the valve. Record the upper and lower shift-point values for the valve. Summary 1 Disconnect the step timing control oil outlet line from the rocker lever housing. Remove the elbow fitting from the rocker lever housing. Install a fitting between the rocker housing and oil outlet line. Connect a 0-300 psi pressure gauge, to the fitting. Summary 2 Disconnect the step timing control fuel pressure sensing line from the fuel inlet passage of the cylinder head. Plug the hole in the cylinder head with a pipe plug. Connect the step timing control fuel pressure line (A) to the outlet side of the air pressure regulator. Connect a 0-160 psi pressure gauge (B), to the air pressure regulator. Connect a shop air pressure line (C), capable of providing 100 psi, to the inlet side of the regulator. Summary 3 Summary 4 Adjust the air pressure regulator until the air pressure gauge shows 0 psi.

Page 4 of 10 Summary 5 Operate the engine at idle. The oil pressure between the step timing control valve and the tappets must be at least 103 kpa [15 psi]. Because the oil pressure can be less than 103 kpa [15 psi] when the coolant temperature is above 49 C [120 F], these tests must be performed at temperatures below this level. Summary 6 If the oil pressure will not reach 103 kpa [15 psi], the step timing control oil delivery system is not functioning properly. Perform the step timing control Oil Delivery System Diagnostics, Procedure 006-045. Summary 7 Slowly adjust the pressure regulator to increase the air pressure until the oil pressure drops below 55 kpa [8 psi]. Record the air pressure at this point. This is the upper shiftpoint (A). The sound of the overhead will become quieter when the 55

Page 5 of 10 to 69 kpa [8 to 10 psi] point is reached. This is the shift from ADVANCED to NORMAL timing. Summary 8 Raise the air pressure at least 103 kpa [15 psi] above the upper shift-point then slowly begin to lower it. Record the air pressure at which the oil pressure raises above 55 kpa [8 psi]. This is the lower shift-point (B). NOTE: The lower shift-point is the shift from NORMAL to ADVANCED timing. The overhead will go from quiet to noisy. This pressure must be lower than the upper shift-point. If it is not, repair or replace the step timing control valve. Summary 9 Compare the shift-point values to those specified for the valve. If the values are not within these specifications listed, recalibrate the step timing control valve. NOTE: Some step timing control valves do not have an adjusting screw. If the calibration is not within specifications, the valve must be removed and repaired or replaced. Step Timing Control Valve Calibration Data Upper Shift Point Lower Shift Point kpa psi 125 MIN 18 193 MAX 28 Not more than 34 kpa [5 psi] below the upper shift point. Summary 10 Remove the tamper proof wire from the acorn nut on the

Page 6 of 10 top of the step timing control valve. Remove the acorn nut from the step timing control valve adjusting screw. Loosen the locknut on the step timing control valve adjusting screw. Summary 11 Use an Allen wrench to turn the step timing control valve adjusting screw. Turn the screw in a clockwise direction to raise the step timing control valve upper shift-point. Turn the screw in a counterclockwise direction to lower the upper shift-point. Summary 12 Always start with the air pressure at 0 psi before checking the upper shift-point (A). Always raise the air pressure to at least 103 kpa [15 psi] above the upper shift-point (A) before checking the lower shift-point (B). After adjusting the screw, repeat the step timing control shift-point check procedure. Summary 13 Repeat the calibration and check procedure until the shiftpoints are within the set values listed in the table. If the valve cannot be calibrated to these specifications, replace it.

Page 7 of 10 Step Timing Control Valve Calibration Data Upper Shift Point Lower Shift Point kpa psi 125 MIN 18 193 MAX 28 Not more than 34 kpa [5 psi] below the upper shift point. Summary 14 Tighten the step timing control adjusting screw locknut. Install the acorn nut on the step timing control adjusting screw. Install the tamper proof wire between the acorn nut and capscrew. Summary 15 Preparatory Steps Clean the step timing oil control valve and the surrounding area before removing it from the engine. Summary 16

Page 8 of 10 Remove the lines from the step timing oil control valve. Refer to Procedure 006-068. Summary 17 Remove Remove the two capscrews which hold the step timing control valve to the mounting plate. Remove the step timing control valve seal ring. If installing an electronic step timing control valve, remove and save the 90 degree check valve fitting and save for use on the electronic step timing control valve. Summary 18 Clean WARNING When using solvents, acids or alkaline materials for cleaning, follow the manufacturer's recommendations for use. Wear goggles and protective clothing to avoid personal injury.

Page 9 of 10 WARNING Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury. Summary 21 Plug all openings to prevent dirt from entering the valve. Use a solvent that will not harm aluminum. Clean the outside of the valve and all the removed parts. Dry with compressed air. Install Install a new seal ring. Install the step timing oil control valve to the mounting plate with the two capscrews. Tighten the capscrews. Torque Value: 41 n.m [30 ftlb ] Summary 22 Summary 23 Finishing Steps Connect the following lines to the step timing oil control valve: Fuel pressure sensing line (1) Oil outlet line to tappets (2) Oil vent line (3). Refer to Procedure 006-068.