Cylinder Bore and Rod Journal Code Locations

Cylinder Bore Diameter





Measure the wear and taper Y at three levels inside each cylinder as shown. If the measurements in any cylinder are beyond the Oversize Bore Service Limit, replace the block. If the block is being rebored, refer to step 7 after reboring.
Scored or scratched cylinder bores must be honed.





Check the top of the block for warpage. Measure along the edges, and across the center as shown.





Calculate the difference between the cylinder bore diameter and the piston diameter. If the clearance is near, or exceeds the service limit, inspect the piston and engine block for excessive wear.

Rod Bearing Selection
Inspect each connecting rod for cracks and heat damage.

Connecting Rod Big End Bore Code Locations





Each rod has a tolerance range from 0 to 0.024 mm (0.0009 inch), in 0.006 mm (0.0002 inch) increments, depending on the size of its big end bore. It is then stamped with a number or bar (1, 2, 3 or 4/I, II, III, or IIII) indicating the range. You may find any combination of numbers and bars in any engine. (Half the number or bar is stamped on the bearing cap, the other half is on the rod.) If you can't read the code because of an accumulation of oil and varnish, do not scrub it with a wire brush or scraper. Clean it only with solvent or detergent.

Connecting Rod Journal Code Location