[213 Lp] Rocker Arms; Description; Installation (Non-Brake And Dynatard Equipped Engines); Installation (Jake Brake-Equipped Engines) - Mack E7 Service Manual

5-101.bk Page 59 Friday, March 17, 2006 11:05 AM

[213 LP] ROCKER ARMS

Description

The valve rockers pivot on a shaft supported by
three brackets per cylinder head. Two capscrews
secure each bracket to the cylinder head. The
rocker arms are operated by a camshaft through
valve lifters and push rods extending through the
cylinder heads. A coil spring returns each valve to
the closed position, holding the rocker arm in
contact with the push rod.
Installation (Non-Brake and
Dynatard Equipped Engines)
Refer to Figure 6-69.
1. Position the rocker arm assemblies on the
cylinder heads.
2. Ensure that the ball end of the rocker arm
adjusters are in position in the push rod
cups.
Make sure that adjusting screws are retracted
upward in the rocker arms. If extended far below
rocker arm, the push rods can be bent when
tightening the rocker arm assembly brackets.
3. Lubricate the threads of the rocker arm
mounting capscrews with clean engine oil.
Install the capscrews and torque to 40 lb-ft
(54 N m) using torque wrench J 24407 or
equivalent.
4. Adjust valve and engine brake slave piston
lash settings as applicable. Refer to the
SETUP AND ADJUSTMENTS section in this
manual for correct specification.
200 ENGINE ASSEMBLY
Installation (Jake Brake-Equipped
Engines)
Use only Jacobs exhaust rocker arm adjusting
screws for Jacobs engine brake installation.
Using a MACK or any other type of screw will
result in severe screw wear and engine damage.
Jacobs exhaust rocker screws have hex heads.
MACK screws have a screwdriver slot.
Refer to Figure 6-70.
Verify that Jacobs exhaust rocker arm adjusting
screws are installed in the exhaust rocker arms.
Turn the screws all the way into the rocker arms
from the underside. Install the MACK locknuts.
1. Install the rocker arm assemblies. Apply
Figure 6-69 — Valve Rocker Arm Installation
clean engine oil to the MACK hold-down
capscrews. Install one capscrew with a
washer in each bracket next to the push
rods. Each rocker assembly has three
brackets.
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