Engine body Grinding of the crankshaft To achieve satisfactory results in connection with grind- i ng the following factors should be taken into considera- tion: I nspection of front crankshaft bushing Check the bearing clearance between the big-end jour- nal and bushing. Use a cylinder indicator and a micro- meter. 1. Grind the crankshaft in a crankshaft grinding ma- chine to the undersize as per "Technical data". Sur- face fineness 1.6 Z ( VVV ) for bearing races (B, Fig. 73) and recess radius are achieved by rub- bing with emery cloth No. 400. Fig. 74. Checking of bearing clearance 1. Measure the bushing's inner diameter at points 1 and 2 as per Fig. 72 on page 46.
Measure in two directions ("A" and "B") at each point. Fig. 73. Checking of recess radius 2. Measure the bearing journal's outer diameter and calculate the bearing clearance (difference be- t ween the previous measurement and the bearing j ournal's max. diameter). 2. I t is very important that the recess radius is the cor- rect size. Recess radius: Max. bearing clearance: 0.2 mm (.0078 in). - At main and big-end bearing journals, "A" = 3 ± 0.25 mm (.1181 ±.0098 in) Replace the bushing if the clearance exceeds the per- missible value. Where necessary the crankshaft can be ground to an appropriate undersize and the bushing can be replaced with a corresponding oversize.
- At oil holes, "C" = min. 2 mm (.0787 in), max. 5 mm (.1968 in). Grinding hacks and sharp edges must be avoided since these can give rise to crankshaft fracture. 3. Clean the crankshaft well from grinding residue and other impurities. Flush and clean the oil channels. Note: Check the bearing clearance again before the crankshaft is fitted if it has been re-ground. I nspection of main and big-end bearings Check the main and big-end bearing cups and the front crankshaft busing. Replace worn bearings or those with damaged bearing surfaces. 4 7