ENGINE AR-PRIM 20R0374 - Caterpillar

Introduction
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.The 525-1901 Rocker Stand has an oil hole drilled into the base of the stand. The purpose of the hole is to allow oil to spray onto the intake valve, providing improved lubrication to reduce valve wear.This procedure will outline how to machine the oil hole into the previous versions of the C175 rocker stand, which will allow the reuse of this part and incorporate the improvement in the 525-1901 Rocker Stand.Rework Procedure
Illustration 1 g06202226
(1) Datum line 01
(2) Datum line 02
(A) 39.3 Degrees
(B) 84.05 mm (3.309 inch)
(C) 42.2 mm (1.661 inch)
The center line of the new oil hole should be located 42.2 mm (1.661 inch) from datum (1) and 84.05 mm (3.309 inch) datum (2) at 39.3 degrees from datum (2).
Locate the hole (D) 12.2 mm (0.48 inch) from the bottom of the rocker base.
Illustration 2 g06202302
(D) 12.2 mm (0.48 inch)
At this location, start the hole with a 3 mm (0.11 inch) center drill to a depth of 2.7 mm.
Drill a 1.6 mm (0.06 inch) hole through the stand and into the middle rocker shaft bolt hole.
The center line of the new oil hole should be perpendicular and intersect the center line of the center rocker shaft bolt hole.
Deburr both ends of the hole.
The oil hole is now complete.