Rocker arm mechanism 6 . Disassemble the rocker arm mechanism and clean the parts . Check the wear of the shaft and rockerarm bush i ngs . Should the bushings need to be replaced, usethe mandrel p/n 9991867 for the removal and installation, (make sure that the oil hole in the bushing coincides with the one in the rocker arm) . After the installation the bushings are reamed to a close running fit . When installing the rockerarm shaft, Replacing the valve seat exhaust port 2003T Grind down the valve disc of a discarded valve to just below 27 mm (1 .063 in) diameter . Push the valve stem through the guide . NOTE! Do not push in too far- the valve disc should be just below the edge of the seat .
Spot weld the disc in place at three points using a electric welder . Knockout the seat by it must be turned so that the lubrication holes are facing the valve-side . Check to make sure that the rocker arm contact surface againstthe valve is concave . Minor adjustments are made in a valve grinding machine . Oil the shaft and install the parts . hiting the valve guide with a plastic-headed hammer . Cool the new seat to approx . -20°C (-4°F) ; the cylinder head should beat room temperature (+ 20°0168°F) . Place the cooled seat on tool 884961-4 and knock it down until it botoms . NOTE! Turn the seat with the valve face towards the tool . Pressure testing the nozzles 7 .
Check the nozzle's spray pattern at the correct opening pressure (see Technical Data) . Check also that the fuel sprays stop simultaneously and no dripping occurs . Adjust the opening-pressure with adjustment-washers (1) being available in different thicknesses from 1 mm U3937 Valve springs 5 . Checkthe free length of the valve springs and the length when loaded . L = Length, unloaded 42,5 mm (1 .67323 in .) L 1 = Length, loaded with 170±10 N (17±1 kp) 32 mm in .) to 1,95 mm ( .076772 in .) in steps of 0,05 mm ( .001969 in .) .
Disassemble the injector and replace the adjustment-washer againstathineroneorathickeronedependingon (1 .25984 in .) L 2 = Length, loaded with 300±20 N (30±3 kp) 24 mm whether the pressure must be reduced or increased . Assemble the injector and check the opening-pressure and the spray-pattern . (0 .94488 in .)