Chevrolet DB90 Series, Service Manual

Page: 72 / 242

S ec. 6C -66
53 AND 71 SERIES DIESEL ENGINES
ENGINE BRAKE-OPTIONAL EQUIPMENT ITEM
SLAVE PISTON-TO-VALVE BRIDGE
CLEARANCE ADJUSTMENT-71 SERIES
DIESEL ENGINE BRAKE
S erv ice Manual ST135-70 g iv e s the s e r v ic e
inform ation for the engine brake (optional equip­
m ent item ) on 71 S e r ie s d ie s e l engines. On page
6C -42 in Section 6C of ST135-70 the sla v e p iston -
to -v a lv e bridge clearan ce adjustm ent is given as
0 .0 6 6 -inch. T his dim ension i s c o r r e c t for a ll 71
S e r ie s engines except those with advanced cam ­
shaft tim ing (N65 brown tag in jecto rs in engines
built after S e r ia l N um bers 6 A -162000 and 8VA-
53550 and sp e c ia lly m odified en g in es. On engines
with advanced tim ing the clea ra n ce adjustment
should be 0.071-in ch .
ENGINE
6V-53 DIESEL ENGINE
The cam shaft gears a re positioned so that the
triangle tim ing m arks are adjacent to each other
(fig. 1). One c ir c le -tr ia n g le tim ing mark on the
id ler gear is aligned with the second "triangle” on
the mating cam shaft gea r. The other tim ing mark
on the id ler gear is aligned with the proper tim ing
m ark on the crankshaft gear.
The crankshaft gear is stam ped "IL-A" and
"A-VR" on the le ft and right sid e of the triangle
tim ing mark (fig. 1). For Standard T im ing, the
"triangle" on the crankshaft gear is aligned with
the c ir c le -tr ia n g le on the id ler gea r. For Advance
Tim ing, the "A" adjacent to the "VR"onthe crank­
shaft gear is aligned with the c ir c le -tr ia n g le on
the id ler gear.
CA M S H A FT G EA R B A LA N CE SHAFT G E A R
TIMING
6-71 DIESEL ENGINE
The cam shaft g ea r s are positioned so the "O"
m arks a re adjacent to each other (fig. 5). One "R"
on the id ler is aligned with the "R” on mating cam ­
shaft gear. The other "R" on the id ler gear is
aligned with the ”R" on the crankshaft gear for
standard tim ing and with the "A" on the crankshaft
gear fo r advance tim ing.
V-71 DIESEL ENGINE
The cam shaft g e a r s are positioned so the "V"
m arks a r e adjacent to each other (fig. 6). The "VR"
mark on the cam shaft gear is aligned with the "R"
on the id ler gea r. The second "R" on the id ler gear
is aligned with the "R" on crankshaft gea r for
standard tim ing and with the "A" on the crankshaft
gear for advanced tim ing.
Figure 5—6-7! Engine Timing Figure 6—V -7? Engine Timing
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT