Chevrolet DB90 Series, Service Manual

Page: 67 / 242

S ec. 6C-61
SECTION 6C
53 a*u£ 71 SeMzi. ^bielel CrnaUiei.
Contents of this sectio n are liste d in Index below:
Subject P age No.
G eneral I n f o r m a t io n ...................................................................................... 61
D ie se l Engine Application C h a r t ........................................................ 61
Advanced Camshaft Tim ing - 6V-53 D ie se l Engine ................... 61
Cylinder Heads - 71 S e r ie s D ie se l E n g i n e s .................................. 61
Cylinder B lock Change - 8V-71 D ie se l Engine .......................... 62
Engine Tune-Up O p e r a t i o n s ....................................................................... 62
V ariable Low Speed L im iting Speed M echanical G overnor . . 62
Torque Requirem ent For Injector Rack Control L ev er S crew s
- 53 and 71 S e r ie s D ie s e l E n g i n e s ............................................. 65
Torque Wrench S p e c i f i c a t i o n s ............................................................ 65
Injector V alve Opening P r e s s u r e .................................................... 65
Engine R eplacem ent - HH and HJ M o d e l s ............................................. 65
V8 D ie se l Engine R e m o v a l ................................................................... 65
Engine Brake - Optional Equipment I t e m ............................................. 66
Slave P isto n -to -V a lv e B ridge C learance Adjustment
- 71 S e r ie s D ie s e l Engine B r a k e ................................................. 66
Engine T i m i n g ................................................................................................. 66
6V-53 D ie se l E n g i n e ............................................................................... 66
6-71 D ie se l E n g i n e .................................................................................. 66
V8-71 D ie se l E n g i n e ............................................................................... 66
Engine Tim ing Chart .................................................................................. 67
Checking Engine Tim ing - 53 and 71 S er ies D ie se l Engines . . 67
Checking Exhaust Valve Springs - 71 S er ies D ie s e l Engine . . 68
T esting and P roblem A n alysis (53 and 71 S e r ie s D ie se l E n g in e s). 69
Information contained in Heavy Duty Truck S erv ice Manual
S T 135-70 on 53 AND 71 SERIES DIESEL ENGINES (SEC. 6C) on pages
6 C -1 —6C -62, is applicable to engines u sed in v e h ic le s covered by this
supplem ent excep t for su b jects indicated by the Index above. The in­
form ation under each of the su b jects either supplem ents, or rep laces
inform ation in S ervice Manuals ST135-70 and ST 332-71, or provides
additional inform ation. Inform ation for the V-71 SERIES DIESEL
ENGINE in S ervice Manual ST 135-70 and in this supplem ent w ill apply
to V 12-71, except as noted in follow ing text.____________________________
GENERAL INFORMATION
DIESEL ENGINE APPLICATION
CHART
HH and JH M odels u se a V8-71 engine which
is mounted at a 12° angle to the right and infor­
mation in S ervice Manual ST135-70 w ill apply,
except as sp ec ifie d in this supplem ent.
ADVANCED CAMSHAFT TIMING
(6V-53 DIESEL ENGINE)
Starting with engine s e r ia l number 6D-66099,
6V -53 d ie se l engines have advanced cam shaft tim ­
ing. T his change w as made to m eet F ederal ex­
haust sm oke em issio n requirem ents that apply to
engines built on or after January 1, 1970. It is not
n e c e ssa r y to advance tim e engines built prior to
th is s e r ia l number.
On advanced tim ed engines, the in scrib ed t r i­
angle mark on the id ler gear should line up with
the point corresponding to "VR-A" on the crank­
shaft (fig. 1). Continue to u se the 1.460" in jector
tim ing gauge (J-1853) with a ll injector s iz e s .
CYLINDER HEADS
(71 SERIES DIESEL ENGINE)
To provide a m ore accurate alignm ent of the
cylinder head to the lin er bore of the cylinder
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT