Continuous use of a boring bar creates wear on the base surface. This condition, when excessive, may produce cylinder bores which are no longer square to the top deck of the cylinder block.

To check if this condition exists use the following procedure:

1. Clamp boring bar in the usual manner and bore one of the center cylinders.

2. Bore the cylinder to .010" oversize.

3. Remove the boring bar and coat the inside of the cylinder bore with Prussian blue or wet the cylinder wall with water and allow to oxidize.

4. Rotate the boring bar 1800 and bore the same cylinder the same size a second time.

5. Out of squareness is indicated when the second cut is out of alignment with the first cut. This means the boring bar must be reconditioned.

(P51)