SERVICE MANUALCONNECTING RODS, PISTONS, RINGS & SLEEVESSection 5CLEANING, INSPECTION & REPAIRClean Connecting Rods as follows:1.Using a non-caustic solution, clean the threadsand mating surfaces between the rod and cap.2.Clean the oil hole at the top of the rod and keepit uncloged.3.Clean all bolts thouroughly.Inspect Connecting Rods as follows:1.Inspect all bolts for nicks or damage. Whenlubricated with SAE 30 oil, the bolts must screwinto the rod face, by hand. If the bolt will notscrew in by hand, reclean the rod threads and trya new bolt. If a new bolt does not screw infreely, the rod must be discarded.NOTE: Do not retap rods as this is a special rolledthread.2.When new bolts are used in a rod, they must betorqued o 175 N•m (130 Ibf-ft), loosened, andretorqued three times.3.Check the integrity of connecting rod bearingbores for mis-match between cap and the rodand for "out-of-round". These checks are onlyvalid when the insert is OMITTED and bolts aretorqued to 175 N•m (130 Ibf-ft) using an SAE 30weight oil as a lubricant under the head of thebolt and in the threads. An inside micrometer isrecommended, but a dial bore gauge can beused for measurements.NOTE: Lack of attention to the integrity ofconnecting rod bearing bores during an overhaulmay result in a rod bearing failure. Careful attentionmust be given to all aspects of the rod and bolts.a.Measure and record the three insidediameters of each rod at points "A", "B"and "C", as shown in Fig. 8.b.If the difference between points "A" and "C"is over 0.10 mm (0.004 in.), the mismatchis excessive and the rod should bediscarded.c.If the difference between point "B" and theaverage of "A" and "C" (A + C divided by 2)exceeds 0.05 mm (0.002 in.), the rodshould be discarded.Figure 8. - Connecting Rod I.D. Measurement locationsInspect Connecting Rod Bearing Fit as follows:1.If bearing-to-crankshaft running clearances areto be reduced, because of wear, install undersizeprecision type bearing shells.a.Premature bearing failure will result fromattempts to reduce journal-to bearingrunning clearances by modifying bearingcaps, bearings or both.b.Such modifying will alter the engineered fitof the bearing shells in their bores anddestroy the specifically desired "crush".2.Bearing shells must fit tightly in the rod or casebore. Bearing manufacturers accomplish this bymaking the diameter at right angles to theparting line (A, Fig. 9) slightly larger than theactual diameter of the bore (B) into which theyare assembled. The increased diameter (C) isrefered to as "bearing crush".CGES-185-3PRINTED IN UNITED STATES OF AMERICAPage 12
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