33 ENGINE2.2LDICOR Valve Seat Inserts l For removing valve seat inserts from cylinder head use suitable boring machine. Bore old insert thin (about 0.5 mm thickness) and then pry it out. l Alternatively use a suitable turning tool to cut an annular groove into valve seat insert and then pull it out with a suitable puller. In order to avoid damaging machined cylinder head mating surface with crank case, place any soft protective sheet metal under supports of puller. l Measure valve seat insert bore diameter in cylinder head. l If boring and prying is done carefully without damaging valve seat insert bore in cylinder head, fitment of an over size valve seat insert will not be necessary. l Re-machined valve seat insert bore in cylinder head must be exactly at right angle to cylinder head mating surface with crank case. l All specified dimensions should be strictly maintained to ensure proper interference of valve seat insert in its bore. l Clean valve seat insert and its bore in cylinder head thoroughly. JUSTBEFOREINSTALLATION l Place valve seat insert in mixture of Methanol and dry ice for about 20-30 minutes to br ing temperature down to -150 deg. C. l Heat cylinder head to approximately 80 deg. in hot water bath. l Install valve seat insert in cylinder head bore quickly by light hammering l Machine valve seat in cylinder head. Fig. 67 CamShaft Inspection l Check cam shaft run out at 2nd journal by support ing i t on V-block at 1st and 3rd journal.(Fig.67) l Check cam shaft journal dimensions. Record the readings. n Carry out visual inspection of cam shaft for: n Overheating of journals, which is indicated by bluish/ brown colour. n Deep scoring marks on journals and cam lobes l Cracks, which should be checked on a magnetic crack detector. l Check hardness of cam shaft journals and cam lobes, it should be 47 HRC
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