ROCKER ARM GP 4N1718 - Caterpillar

All 3500 Diesel Commercial EnginesReference: Guideline For Reusable Parts And Salvage Operations, Form No. SEBF8283, "Reworking Cylinder Head Bolt Holes on 3500 Engines"A chamfer (4) has been added to the three cylinder head bolt holes (1, 2, and 3) on the bottom of the engine cylinder head. These holes are in the exhaust side of the cylinder head. See Illustrations 1 and 2. These three holes are the most sensitive to high temperatures and high cycles. The addition of the chamfer reduces the possibility of cracks in these areas.
Location of the three cylinder head bolt holes (1, 2, and 3) that have the chamfer.
(SECTION A-A) [1.2 0.5 mm (.05 .02 in) X 45 degree Chamfer (4).The chamfer can be added to the cylinder head bolt holes in earlier cylinder heads. The Referenceprovides complete information for machining the radius.