Chevrolet BEAUVILLE SPORTVAN G10 SERIES, Service Manual

Page: 146 / 350

ENG INE 6-17
and rem ove d istrib u to r cap and plug wire assem bly
(if n o t previously done).
b. C rank engine u n til d istrib u to r ro to r points to
nu m b er one cylinder positio n an d b reaker points
are open. The following valves can be adjusted w ith
engine in n u m b er one firing position.
N um ber one c y lin d e r-E x h a u s t and In tak e
N um ber tw o c y lin d e r-In ta k e
N um ber three c y lin d e r-E x h a u st
N um ber four c y lin d e r-In ta k e
N um ber five c y lin d e r-E x h a u s t
c. Back o u t adjusting n u t u n til lash is felt at the push
ro d th e n tu rn in adjusting n u t u n til all lash is
rem oved. Tliis can be determ ined b y checking push
ro d end play while tu rn in g adjusting n u t (Fig. 5L ).
When play has been rem oved, tu rn adjusting n u t in
one full additional tu r n (to c e n te r lifter plunger).
d. C rank engine u n til d istrib u to r ro to r points to
num ber six position and b reaker p o ints are open.
The follow ing valves can be adjusted w ith engine in
num ber six firing position:
N um ber tw o c y lin d e r-E x h a u st
N um ber th ree c y lin d e r-In ta k e
N um ber four c y lin d e r-E x h a u st
N um ber five c y lin d e r-In ta k e
N um ber six c y lin d e r-In ta k e and E xhaust
4. Install d istrib u to r cap and spark plug wire assem bly.
5. Install rocker arm cover as outlin ed .
6
. A djust carb u reto r idle speed and m ixture.
Valve Lifters
H ydraulic valve lifters very seldom require a tte n tio n . The
lifters are extrem ely sim ple in design, readjustm ents are n o t
necessary, and servicing o f th e lifters requires only th a t care
and cleanliness be exercised in th e handling o f parts.
Locating Noisy Lifters
L ocate a noisy valve lifter b y using a piece o f garden hose
approxim ately fo u r feet in length. Place one end o f th e hose
near th e end o f each intake and exhaust valve w ith th e o th e r
end o f th e hose to th e ear. In this m anner, th e sound is
localized m aking it easy to determ ine w hich lifter is at fault.
A n o th er m e th o d is to place a finger on th e face o f th e valve
spring retainer. I f th e lifter is n o t functioning p roperly, a
d istinct shock will be felt w hen th e valve returns to its seat.
The general types o f valve lifter noise are as follows:
1. H ard R apping N oise—Usually caused b y th e plunger
becom ing tig h t in th e bore o f th e lifter b o d y to such an
e x te n t th a t th e re tu rn spring can no longer push the
plunger b ac k up to w orking position. Probable causes
are:
a. E x c e s s iv e varnish or carbon deposit causing
abnorm al stickiness.
b. Galling o r “ p ic k u p ” betw een plunger and bore o f
lifter b o d y , usually caused by an abrasive piece o f
d irt or m etal wedging betw een plunger and lifter
b ody.
2. M oderate R apping Noise—Probable causes are:
a. Excessively high leakdow n rate.
b. L eaky check valve seat.
c. Im p ro p er ad ju stm en t.
3. G eneral Noise T h ro u g h o u t the Valve T rain—This will, in
m ost cases, be caused b y eith er insufficient oil supply or
im proper ad ju stm en t.
4. In te rm itte n t Clicking—Probable causes are:
a. A m icroscopic piece o f d irt m o m entarily caught
betw een ball seat an d check valve ball.
b. In rare cases, th e ball itself m ay be out-of-round or
have a flat spot.
c. Im proper ad ju stm en t.
In m ost cases, w here noise exists in one or m ore lifters, all
lifte r u nits should be rem oved, disassem bled, cleaned in a
solvent, reassem bled, an d reinstalled in th e engine. If dirt,
varnish, carbon, etc. is show n to exist in one u n it, it m ore th a n
likely exists in all th e units, th u s it w ould only be a m a tte r o f
tim e before all lifters caused tro u b le.
Removal
1. Rem ove valve m echanism as outlined.
2. M ark d istrib u to r housing, w ith chalk, a t nu m b er one and
nu m b er six cylinder position (plug wire) th e n disconnect
plug wires a t spark plugs and coil and rem ove distrib u to r
cap and plug wire assem bly.
3. C rank engine u n til d istrib u to r ro to r points to num ber
one position, th e n disconnect d istrib u to r prim ary lead at
coil and rem ove d istrib u to r.
4. Rem ove p ush ro d covers (discard gaskets).
5. Rem ove valve lifters.
N O T E : Place valve lifters in a rack so th ey may be
reinstalled in the same location.
Installation
Fig. 5 L - V a lv e A djustm ent 1.
Install valve lifters.
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C H E V Y V A N S H O P M A N U A L