1.2 CYLINDER HEAD 1.2.3.5 Inspection and Reworking of Head Bolt Counterbore To assure clean and non-brinnelled cylinder head bolt counterbores, use J–38189 to resurface the head bolt washer area. The procedure and steps for proper use of the tool are as follows: NOTICE: There must be no space between the bottom of the cylinder head and the table top to properly resurface the counterbores. 1. Place the cylinder head on a solid flat surface (preferably a steel table top) that completely covers the bottom of head. NOTICE: Proper use of the J–38189 is important. Failure to use J–38189 properly may result in an incorrect counterbore depth. 2.
Protect the valve springs and injector counterbore to keep any loose metal shavings from getting into valve springs and counterbore during cutting operation. 3. With cylinder head on a flat surface using the 1/8 in. hex wrench supplied with tool, loosen the stop collar and cutter to permit sliding on pilot. 4. Starting at the front of the cylinder head, place the pilot of the cutter into a cylinder head bolt hole until the pilot contacts the flat surface beneath the cylinder head. 5. Allow the cutter to contact the counterbore surface. Lock the stop collar while against the cutter. The cutter now will resurface the counterbore 0.508 mm (0.020 in.). 6. Remove the tool and place a 0.020 in.
feeler gage between the cutter and the locked stop collar. 7. With feeler gage in place, lock the set screw of the cutter, then remove the feeler gage and loosen the set screw on the stop collar and slide it down tight against the cutter and retighten. Perform the following steps to resurface the counterbore 0.508 mm (0.020 in.): 1. Using a drill motor with a 1/2 in. chuck and a maximum of 450 r/min and a suitable cutting oil to prolong the life of the cutter and to lubricate the pilot turning in bolt hole, 2.
Apply a moderate pressure on the drill motor, continue cutting operation until pilot bottoms on flat surface and then do not stop drill motor until after being lifted from cutting surface. This is to eliminate surface marks. NOTE: The J–38189 tool pilot has a shoulder stop that will not allow the cutter to remove material in excess of the Detroit Diesel Corporation specifications. (Rev. 2005) All information subject to change without notice. 1-52 6SE483 0507 Copyright © 2005 DETROIT DIESEL CORPORATION