01.8 Removal and installation of valve seat rings 352/352 A' 9 Slacken screw of quick·action adjuster (1) until tool has reached. yet does not yet touch valve seat ring. Tighten lock·nut (2). Turn horizontal stop screw (3) fully home against body and then slacken by 2 to 3 mm. Tighten clamping screw (4) beneath. 10 Adjust tool height so that about 1 mm metal is left on valve seat ring at bottom after machining. Note: Hold knurled collar (2) and turn cutter crank clockwise. so moving tool downwards. Turning anti· clockwise serves to raise tool. 11 Turn tool and simultaneously hold knurled col· lar (2) which has to be briefly released as torsion in· creases slightly.
This serves to turn groove in valve seat ring to depth of about 2 to 3 mm. Note: Avoid coarse cuts. Cutter must always turn easily. this being achieved by briefly releasing knurled collar (2). 12 Remove cutter. 13 Fit internal remover in annular groove, tighten nut and draw out using counter·support. Note: Place copper strips beneath counter·support to avoid damaging cylinder head face. 14 Adjust internal measuring instrument using micrometer. 15 Measure bores for valve seat rings in cylinder head, using internal measuring instrument. Note: Holes are to be bored to next step should table values not be reached. See 1.2/4 for repair stages, 16 Remachine basic bore. referring to 6,5/1. 6.4/2