1979 Diesel Engine Piston Identification Chart m lc Y mifi z 7Z s v E II In Q I I I Irl I I mul i r u s 2 i r g mi laiamasrvi t g msmnsizs tsl V numeric nriqmiimiill M nlxlnn in mia Fig 0lA CyIinder Bore Marking Fig 0lB Measuring Piston cu nun mrcm mma m nu me im smcriun ann sms szrzmim mma sur vision nu nun ctzmncz lmww msec osss n msos os1o S n mess os1o I 0sm mais nsogIBI o5z5 I W n5 n 4 usm os1s c mais com gm M n wszs 4 0sau n com J nszs gm to mm n mesa nsss J us s wm 4 3 3 gu csss 4 0670 I 4 osm mais cases mms i i 4 0610 4 0615 V L 4 0svs ns20 ll J u os1s usso n mszn mszs Fig 01C Piston Informafion Chart Checking Cylinder Bore When replacing pistons the original cylin der size is stamped with a code letter on the Cylinder bore size can be measured with in block near each cylinder on the oil pan rail side micometers or a cylinder gage Fig 01Al Maximum allowable taper ofthe cylinder bore Whoo MBBSUHHQ PISYUN for Silo UT t8P l r is 001 The most wear will occur at the top of measurement must be made on skirt 90 from the ring travel piston pin hole with the piston pin removed Reconditioned cylinder bores should be lFi9 0lBl held to not more than 001 out of round and Vllhen measuring taper measure at the cen 001 taper terline of the piston hole and at the bottom of If the cylinder bores are smooth the cylin the skirt The largest reading must be at the der walls should not be deglazed If the cylin bottom of the skirt Allowable taper is 000 to der walls are scored the walls may have to be 002 I I honed before installing new rings lt is impor The piston and cylinder bore must be free of tant that reconditioned cylinder bores be oil and at the same temperature thoroughly washed with a soap and water so Iution to remove all traces of abrasive material NOTICE On some vehicles oversize pistons to eliminate premature wear may be found These pistons will be 010 oversize Measuring Each piston should be fitted to its individual NOTICE Refer to PISTON INFORMATION cylinder and marked for that cylinder Piston J CHART FIGURE 01C to bore clearance is 005 to 006 T WAREHOUSING Ann msrnisurion Division or GENERAL morons coni onATion isi muck szA t as REV 1 84