Mack E7, Руководство по обслуживанию

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200 ENGINE ASSEMBLY
Page 6-23
Figure 6-23 — Buttress Capscrew Locations
After obtaining proper main bearing clearance:
1. Check torque of main bearing capscrews:
210 lb-ft (285 N 폷 m) using torque wrench
J 24407 or equivalent.
2. Torque the buttress capscrews to 90 lb-ft
(122 N 폷 m) using torque wrench J 24407 or
equivalent.
[212 NP & 212 LP] PISTONS
AND CONNECTING RODS
Description
Since 1991, all E7 engines have used a two-
piece piston. To ensure a continued high level
of piston durability, the piston crown is made of
forged steel and the piston skirt is made of cast
aluminum. The piston pin bore pedestal and skirt
are stamped FRONT and must face the front of
the engine. These production parts are not
interchangeable with 1989/1990 production.
The piston design incorporates two compression
ring grooves and one oil control ring groove. A
plasma-faced keystone type ring is used in the
top location. A tapered chrome rectangular-type
ring is used in the second ring groove. The oil
control ring is located in the third or lower ring
groove, nearest the piston pin bore. The new
piston rings are designed to further improve oil
and particulate control.
Special Tools Required
앫
Piston Ring Compressor J 23442 or Piston
Ring Compressor PT7070-A
200340a
RIGHT SIDE OF ENGINE
80 mm
80 mm
80 mm
110 mm
1
2
1
1
BOTTOM VIEW
FR
ONT
OF
VEHICLE
1. 80-mm buttress capscrews 2. 110-mm buttress capscrews
5-101.bk Page 23 Friday, March 17, 2006 11:05 AM