Caterpillar — Overhead Adjustments

Adjustments · Rocker arms, crossheads and oil supply

From a Caterpillar service manual — check it applies to your exact model before use.

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Procedure

1. Apply clean oil to the crosshead bore, install on the engine and adjust according to the Caterpillar manual.
2. Check clearance between the underside of the crosshead on the adjusting screw side and the top of the valve rotocoil.
3. Remove the front dowel pin; lubricate and install the Pacbrake oil supply adapter leaving about .020 gap at the pedestal.
4. Remove the rear locating pin and replace it with the longer Pacbrake pin, rounded end up, driven until it stops.
5. Using air pressure, remove oil trapped in the holddown bolt holes; wear eye protection.
6. Re-install the front rocker assembly, ensuring the push-tubes are in place.
7. Install the two Pacbrake studs with Pacbrake washers in the outside locations; reuse the Caterpillar bolt and washer in the center.
8. Apply 6V4876 molykote paste on the threads and between the washer and the underside of the bolt head and stud hex.
9. Torque the bolts and studs to 200 lb.ft. (270 N.m), then to 330 lb.ft. (450 N.m) in 50 lb. (70 N.m) increments.
10. Repeat steps on the rear.
11. Remove Cat head bolts on the front of the engine, blow out oil, and lubricate the threads and bearing surfaces.
12. Install the Pacbrake support base reusing the Cat head bolts and washers and torque to 330 lb.ft. (450 N.m).
13. Install the housing support studs into the support bases (hex nut end into base) and torque to 50 lb.ft. (70 N.m) using a 9/16 crowfoot wrench.
14. Install the 7/16 NF nuts and washers and run the nuts to the bottom of the threads.
15. Repeat steps on the rear.

Source: Caterpillar service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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