Heathkit CI 1040 Service Manual

Page 1

Mod-I (II-1040 12-Volt Automotive Duluxo Timing light

: ""fl (El-1040 12-Volt Automotive
;: Deluxe Timing Light
Ea: HEATH KIT®
SE ASSEMBLY MANUAL

Copvvight © 1 972
Hemh Company
W nuili- Ii u n .11

% HEATHKIT-

Price $2.00

595-1466-03

Page 2

Deer Customer:

The Heethltlt electronlc product you hove purcneeed le one at the best performlng electronlc products In the
world.

Here't how we elm to keep It the! my:

Your Heathklt- Warranty

Durlng your llttt 90 any: at ownership, eny peru- whlch we "no ere delectlye, elther ln metorlele or
workmanship. wlll be reoleced or rep-bred lree of chemo. And well pey thlpplng energet to get those pert: to
you - enywhere in the world.

It we determlne e delectlye pert net ceueetl your Heethltlt electronic product to need other repelr, through no
leult o! youn. we will tervlce lt free - et the lectory, et eny retell Heetltltlt Electronlc center, or through eny of
our eutltorieeo overeat dietrlbuton.

Tnle protectlon ls exclusively your: es the orlglnel ourcheeer. Neturelly, it doesn't-cover demege by~uee of
eclocore solder. incorrect uternbly. rnltuee. lire. flood or ecu ol Goo. But. lt doe: lneure the pedorrnenoe or
your Heetnklt electronic product enywnere m the world - (or most eny other reeeon.

Alter-Wettenty Service

What heooens utter werventy? We wont let you down. It your Heetltltlt electrenlc product needs reoelrs or you
need I pert. )utt write or cell the lectory. your nearest retell Heethklt Electronlc Center. or eny Heath
euthorlzed memes dlstrlbumr. We melnuln en Inventory of replecernent pert: for eech Heethltlt model et most
locetlone - even tor meny model: thet no longer eooeer In our current product line-up. Repelr seryloe end
technlcel oomltlflon ere evelleble throuoh ell locatlnm.

KT?
We hope you'll nmr need our repelr or reokoernenl terylces. but lt't nlce to know you're protected enywey - g:
end thet cheertul help lt neerby. pt

Sincerely.

:5,
E:
HEATH COMPANY 55,15
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Benton Heroor. Mlcltlgen £9022

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Prices and specifications subject to change with'Out notice.

Page 37

-HEATHKIT'

Page 29

THEORY OF ENGINE OPERATION

HOW TIMING WORKS

This section of the Manual explains the principles of operation of a 4-cycle
engine (used in most automobiles). To understand how ignition timing works in
an engine, read this section thoroughly.

Refer to Figure 5 (fold-out from Page 26) for an illustration of the basic
principle of operation of a 4cycle (4 strokes per cycle) engine. Only the #1
cylinder of the engine is shown. All the other cylinders of the engine operate in
the same manner, going through the same four strokes per cycle as the #1
cylinder does. The sequence of operation of the other cylinders is determined by
the engine design and by the firing order of the engine.

® Intake Stroke

0n the intake stroke, the piston moves down, the exhaust valve closes, and the
intake valve of the engine opens, admitting the fuel mixture to the engine.

® Compression Stroke

On the next stroke, the intake valve closes, and the piston moves up toward the
head of the engine to compress the fuel mixture. At a certain "timed" instant, as
the piston is still moving up, the spak plug fires and ignites the fuel. The
distributor determines the timing of the spark.

® Power Stroke

The fuel mixture, which has been ignited by the spark plug, requires
approximately 1/350th of a second to burn completely. Depending on the speed
at which the engine is operating, the fuel will still be burning for a certain
amount of time after the piston reaches "top dead center (T00) and has
started down on the power stroke. The force of expansion of the burning fuel
pushes the piston down and gives the engine its power.

G) Exhaust Stroke

When the piston moves up again, the exhaust valve opens, releasing the burned
fuel. This prepares the engine to take in fuel again for the intake stroke which
follows the exhaust stroke.

Top Dead Center

The crankshaft of the engine rotates through 180 degrees for each stroke of the
piston. At the highest point of piston travel, the piston is at "top dead center"
(TDC). All ignition timing, as specified by the engine manufacturer, is measured
in degrees of crankshaft rotation from the point where the piston is at top dead
center.