Valve Lifters; Locating Noisy Lifters - Chevrolet CHEVY VAN G10 SERIES Service Manual

and rem ove d istribu to r cap and plug wire assembly
(if n o t previously done).
b. C rank engine until distributor ro to r points to
num ber one cylinder position an d breaker points
are open. The following valves can be adjusted w ith
engine in num ber one firing position.
N um ber one c y lin d e r-E x h a u st and Intake
N um ber tw o c y lin d e r-In ta k e
N um ber three c y lin d er-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 st
c. Back o u t adjusting nut u n til lash is felt at the push
rod th e n tu rn in adjusting n u t un til all lash is
rem oved. Tliis can be determ ined by checking push
ro d end play while tu rning adjusting n u t (Fig. 5L).
When play has been rem oved, tu rn adjusting n u t in
one full additional tu rn (to cen ter lifter plunger).
d. C rank engine until d istrib u to r ro tor points to
num ber six position and breaker points are open.
The follow ing valves can be adjusted w ith engine in
num ber six firing position:
N um ber tw o cy lin d er-E x h a u st
N um ber three cy lin d e r-In ta k e
N um ber four cy lin d er-E x h a u st
N um ber five cy 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 distributor cap and spark plug wire assembly.
5. Install rocker arm cover as outlined.
6
. A djust carburetor idle speed and m ixture.

Valve Lifters

H ydraulic valve lifters very seldom require atten tio n . The
lifters are extrem ely simple 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.
Fig. 5 L -V a lv e Adjustm ent
i

Locating Noisy Lifters

Locate a noisy valve lifter b y using a piece o f garden hose
approxim ately four feet in length. Place one end o f the hose
near the end o f each intake and exhaust valve w ith th e oth er
end o f the hose to th e ear. In this m anner, th e sound is
localized making it easy to determ ine which lifter is at fault.
A nother m eth od is to place a finger on th e face o f the valve
spring retainer. I f th e lifter is n ot functioning properly, a
distinct shock will be felt when the valve returns to its seat.
The general types o f valve lifter noise are as follows:
1. H ard Rapping N oise— Usually caused b y the plunger
becom ing tight in th e bore o f the lifter b ody to such an
ex ten t th a t th e retu rn spring can no longer push the
plunger back up to w orking position. Probable causes
are:
a.
b.
2. M oderate Rapping Noise— Probable causes are:
a.
b.
c.
3. General Noise T h rou ghout the Valve T rain— This will, in
m ost cases, be caused b y either insufficient oil supply or
im proper adjustm ent.
4. In term itten t Clicking— Probable causes are:
a.
b.
c.
In m ost cases, where noise exists in one or m ore lifters, all
lifter units should be rem oved, disassembled, cleaned in a
solvent, reassem bled, and reinstalled in th e engine. If dirt,
varnish, carbon, etc. is show n to exist in one u nit, it m ore th an
likely exists in all the units, thus it w ould only be a m atter o f
tim e before all lifters caused trouble.
Removal
1. Remove valve m echanism as outlined.
2. M ark distributor housing, w ith chalk, at num ber one and
num ber six cylinder position (plug wire) th en disconnect
plug wires at spark plugs and coil and remove distributor
cap and plug wire assembly.
3. C rank engine u n til distributor ro to r points to num ber
one position, th en disconnect d istribu tor prim ary lead at
coil and remove distributo r.
4. Remove push rod covers (discard gaskets).
5. Remove valve lifters.
N O T E :
reinstalled in the same location.
Installation
Install valve lifters.
1.
1
*
E x c e ssiv e varnish or carbon
abnorm al stickiness.
Galling or " pickup" betw een plunger and bore o f
lifter b o dy, usually caused by an abrasive piece o f
dirt or m etal wedging betw een plunger and lifter
body.
Excessively high leakdow n rate.
Leaky check valve seat.
Im proper adjustm ent.
A m icroscopic piece o f d irt m om entarily caught
betw een ball seat an d check valve ball.
In rare cases, th e ball itself m ay be out-of-round or
have a flat spot.
Im proper adjustm ent.
Place valve lifters in a rack so they may be
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ENGINE 6-17
deposit causing
C H E V Y V A N SH O P M A N U A L