35604330-TACH-DWELL-Tester-Instructions.pdf

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TACH-DWELL

TESTER

MODEL 3010

OPERATING

INSTRUCTIONS


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GENERAL INFORMATION

Your new Tune-Up Tester utilizes a d'arsonval meter, the most accurate and dependable type

meter movement available. This most precise meter insures greater reliability and ruggedness.

The latest solid state electronics assure years of trouble-free use.

TACHOMETER /DWELL CONNECTIONS: (FIG. 1)

On all gnition !ystems, the blac" lead should be connected to chassis or negative terminal of

battery. The red lead should be connected as follows

STANDARD IGNITION - (POINTS)

#onnect red lead to distributor side of coil, either at coil or distributor points.

ELECTRONIC IGNITIONS

$. %eneral &otors igh (nergy gnition )(*. - #onnect red lead to tachometer terminal

mar"ed +T#.+

. ord )&otorcraft*, #hrysler, merican &otors )/0*, nternational arvester )l-* and most

&agnetic and Optic #oupled Transistorized gnition !ystems. - #onnect red lead to negative

side of coil or most convenient tie point from negative side of coil.

1 #apacitive 0ischarge gnitions )#0*, 0elta &ar" Ten /, #ompu-!par". -!witch unit to

conventional mode and connect red lead to negative side of coil. f unit does not have this feature,

signal can be ta"en from points signal directly at distributor.

2hen reference is made to negative ground, this means that the minus

)-* battery terminal is connected to the chassis. 2hen the positive )3* terminal is connected to

the chassis, this is referred to as positive ground.

This instrument is designed for use on $ volt ignition systems only.

ZERO ADJUSTMENT

4rior to hoo"up, hold your instrument in normal use position. f necessary, ad5ust screw on the face

of the meter until pointer reads +6+ on tach or 789:;69 on dwell scales.


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DWELL TACHOMETER

The 0well Tachometer is an essential tool for the tuneup and repair of any vehicle. The name of the

instrument is basically a short form of the two functions that it performs= gnition 4oint )#am 0well*

&easurement and engine dle speed in revolutions per minute )>4&*.

The idle tachometer function consists of=

a. d5usting dle !peed

b. ,ir uel >atio #hec"

c. #hec"ing #ylinder 4erformance

d. #entrifugal dvance Test

e. #hec"ing the ir ilter

The cam dwell function measures the action of the distributor brea"er points and permits

accurate ad5ustment to avoid misfiring during high speeds, acceleration, hill climbing or trailer

towing. ccurate ad5ustment of the dwell angle also helps to prevent point burn-out and

fosters easier starts. The test consists of ad5usting the point gap through the

measurement of ignition point cam dwell angle.


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IDLE TACHOMETER FUNCTION

a. ADJUSTING IDLE SPEED$. /efore ad5usting idle speed, the engine must be warm )normal operating

temperature*, the carburetor butterfly cho"e must be open and the carburetor fast idlecam in slow position. )?ote= These are the normal positions for operating

temperatures.*

. >emove the air filter.

1. d5ust the carburetor idle screw to bring the idle speed to the >4& range specified by

the manufacturer of your vehicle.

b. AIR FUEL RATIO CHECK

$. 2ith the engine idling at manufacturer specified speed, perform the following=

. 4lace a flat plate slowly over the air horn of the carburetor to partially cho"e off theinta"e of air. ?ote the >4&.

>esults=a. ncrease in engine speed indicates a lean mi@ture.

b. 0ecrease in engine speed indicates a rich mi@ture.

c. Aittle change until the air is almost completely shut off indicates

an acceptable air-fuel ratio.

?ote= The best ad5ustment of the idle fuel mi@ture can be obtained by using a Bacuum: uel

4ump Tester in con5unction with the dle Tachometer. The vacuum tester insures smooth

engine operation at the most economical setting of air to fuel ratio.

. CHECKING C!LINDER PERFORMANCE$. !et engine speed at $,666 >4&.

. !hort out each spar" plug one at a time and note the decrease

n >4&.

>esults=Those cylinders that are not performing at top efficiency will havea lesser effect on overall engine speed )>4&* when shorted out.

". CENTRIFUGAL AD#ANCE TEST$. gain operate the engine at normal idle speed.

. Aoosen the loc" screw on the case of the distributor and rotate the distributor body, left or

right, until ma@imum engine speed is obtained.


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1. ncrease the engine speed to $,666 >4& and again try to increasethe speed by rotating the distributor body. Tighten distributor

loc" screw.

>esults=

f the engine speed can be increased more than $66 >4& in !tep

1, then the centrifugal advance mechanism is not operating correctly.

7. >e-time the ignition with a timing light per manufacturer's specifications.

$. CHECKING THE AIR FILTER$. >emove the air filter

. gain, with the engine idling at manufacturer's specified speed, replace the air filter.

>esults=ny reduction in >4& indicates a dirty or damaged air cleaner.

CAM DWELL FUNCTION

CAM DWELL ANGLE MEASUREMENT (P%&' Ga)$. The distributor in some vehicles has an llen screw fitting so that the 0well ngle )pointgap* can be set from the outside of the distributor while the engine is running. On these

vehicles, simply lift the window protecting the llen screw and ad5ust the angle to the

manufacturer's specification while observing the meter

. On vehicles where the point gap is ad5usted on the inside of the distributor, remove thehigh tension wire >O& T( 0!T>/UTO> ?0 %>OU?0 T /Y #O??(#T?% T TO#!!!. >emove the distributor cap. &easure the dwell angle while cran"ing the engine. tcran"ing speeds, the pointer on the meter will vibrate. Use the reading half way between thee@tremes of the vibrating pointer as the dwell angle measurement.

1. d5ust the dwell angle by changing the gap opening of the points.

?ote= f the dwell angle is too low the point gap is too wide.

f the dwell angle is too high, the point gap is too close.

7. >eplace the distributor cap and high tension wire. 2ith the engine

running, ma"e a final measurement of the dwell angle and re-ad5ust

as necessary.

8. >e-time the ignition with a timing light per manufacturer's specifications.


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35604330-TACH-DWELL-Tester-Instructions.pdf