Inspection

Block and Piston Inspection






















Inspection

1. Block and Piston - Inspection

1. Remove the pistons from the engine block.

* Check the pistons for distortion or cracks.
* Measure the piston diameter at a point 13 mm (0.51 in) from the bottom of the skirt. There are two standard-size pistons (No Letter or A, and B). The letter is stamped on the top of the piston. Letters are also stamped on the engine block as the cylinder bore sizes.























2. Measure the wear and taper in direction X and Y at three levels in each cylinder as shown.
If the measurements in any cylinder are beyond the Oversize Bore Service Limit, replace the engine block.
If the engine block is being rebored, check the piston-to-cylinder bore clearance.

























3. Hone any cored or scratched cylinder bores if needed.

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












5. 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 cylinder bore for excessive wear.











Honing

1. Cylinder Bore - Honing

1. Hone the cylinder bores with honing oil and a fine (400 grit) stone.








NOTE:
* Use only a rigid hone with 400 grit or finer stone such as Sunnen, Ammco, or equivalent.
* Do not use stones that are worn or broken.






2. When honing is complete, thoroughly clean the engine block of all metal particles. Wash the cylinder bores with hot soapy water, then dry and oil them immediately to prevent rusting.

NOTE: Never use solvent, it will only redistribute the grit on the cylinder walls.

3. If scoring or scratches are still present in the cylinder bores after to the service limit, rebore the engine block. Some light vertical scoring and scratching is acceptable if it is not deep enough to catch your fingernail, and does not run the full length of the bore.