[212 Np] Locating Piston Top Dead Center (Tdc); E7 Series Engines With Front Timing Indicators; Special Tool Required; Locating Piston Tdc - Mack E7 Service Manual

5-101.bk Page 21 Friday, March 17, 2006 11:05 AM
[212 NP] LOCATING PISTON
TOP DEAD CENTER (TDC)
E7 Series Engines with Front
Timing Indicators
During timing inspection, if timing is found to be
incorrect, check piston TDC and retime engine.
The following instructions are provided to aid in
locating piston TDC in the event the engine front
timing pointer is bent or misaligned.
On engines with front timing indicators, vibration
damper is marked to show TDC location relative
to No. 1 piston on compression stroke. After
locating piston TDC, front timing indicator may be
adjusted slightly until it aligns with the TC or "0"
mark stamped on vibration damper.

Special Tool Required

Top Dead Center Indicator Tool J 29539-A

Locating Piston TDC

If chassis is equipped with an engine stop control,
pull control out to prevent accidental starting.
Refer to Figure 7-37.
1. Rotate engine in normal rotation direction
until No. 1 piston is approximately at TDC on
compression stroke.
2. Remove injection nozzle holder assembly
from the No. 1 cylinder (front cylinder on E6
and E7 engines).
3. Install TDC indicator tool J 29539-A in
nozzle holder opening.
4. Rotate engine in normal rotation direction
until the highest reading is obtained on the
dial indicator. At this point, zero dial
indicator.
5. Center a 5-inch (127 mm) length of masking
tape below the pump timing pointer and on
the vibration damper.
200 SETUP AND ADJUSTMENTS
6. Rotate engine in direction opposite to
normal rotation until a reading of 0.060 inch
(1.524 mm) is obtained on the dial indicator.
7. Rotate engine in normal rotation direction
until dial indicator reads exactly 0.035 inch
(0.889 mm).
8. Place a mark on the masking tape on the
vibration damper to align with pump timing
indicator pointer.
9. Rotate engine in normal rotation direction
past zero on dial indicator until a reading of
0.060 inch (1.524 mm) is obtained.
Figure 7-37 — Locating Piston TDC
Page 7-21