Mallory Ignition 23, 25, 27 User Manual

Mallory Distributors Manual

Standard And Vacuum Advance

Single And Dual Point

TROUBLESHOOTING GUIDE FOR
A POINT STYLE DISTRIBUTOR

The following are some basic steps to take when
troubleshooting a Point Style Distributor. Of course,
the first thing that should be checked is the condition
of the cap and rotor, looking for carbon tracking or
corrosion on the terminals or where the plug wires
connect. Also check the spark plug wires with an
Ohmmeter to insure they have the proper resistance.

IF THERE IS NO TRIGGER SIGNAL TO THE COIL

If the box powers up but does not fire the coil and the
white wire is being used as the trigger source, the
following tests should be done:

1. Remove the cap, turn the motor over and look at
the points to see if they are opening and closing. If
they are, see if they are sparking. On a dual point
distributor, one set will open with no spark and the
other will spark when it opens. If the spark is a big
fat one, then the condenser is bad and needs to
be replaced.

2. If no spark is visible, check to see if the points or
wires are shorting to ground either at the points or
at the primary terminal screw going through the
housing. Also check where the contact spring
connects to the main frame of the points and
make sure the insulator is not melted.

3. If all of this looks good then look to see if there is
anything else connected to the coil (-) terminal. If
so, remove it and see if the motor fires.

4. Last but not least, there could be a problem with
the coil itself or the coil wire going back to the cap.
To check the coil, use the following test procedure.
NOTE: This test should only be done on "stock
type" coils. DO NOT try this test with "CD Only"
coils, such as the Mallory 28880 or ACCEL 140019
and 140010.

1. Disconnect the distributor from the coil (-)
terminal, taking it out of the loop and
allowing the test to be done properly.

2. Disconnect the wires coming from the CD
box (if so equipped) connected to the coil
(+ and -) terminals and connect the ignition
switch 12 volts wire to the coil (+) terminal
of the coil.

3. Connect a 24" piece of wire to the coil (-) of
the coil.

4. Pull the coil wire out of the distributor cap
and get it to where you can jump a spark to
ground with it.

5. Turn the ignition to the "ON" position.

6. Rapidly tap the 24" wire to ground. This will
fire the coil. You should get a 1/4” to 3/8”
spark out of the high voltage coil wire to
ground. If you do then the coil and coil wire
are good and working.

7. If no spark to ground, change out the coil
wire and do the test again. If still no spark,
the coil is bad and needs to be replaced.

IF THE POINTS BURN UP OR THE CONDENSER
FAILS FREQUENTLY

1. Check and make sure that everything is well
grounded to the engine block. Condenser failure
is often a grounding problem. Make sure all
grounding surfaces are clean of free of paint,
grease, or oil.

2. If the condenser needs changing, make sure that
the bracket is also changed at the same time. The
brackets are basically a one-shot use part. They
are designed to scratch through the rust
preventative coating on the condenser when it is
installed. In problem applications, scuffing off this
coating will guarantee a good ground.

3. Make sure that the heads are grounded to the
block. With all of the coatings and sealers that are
used on gaskets and bolts, especially on race
applications, the cylinder heads can be poorly
grounded. A simple ground strap between the
block and each head can make a big difference.

4. A simple ground strap from the distributor body to
the block, not the intake manifold can also solve a
problem. The strap can be connected to a screw
that attaches the vacuum advance chamber or the
condenser bracket. Care must be taken that the
screw is replaced with a slightly longer one to allow
for the thickness of a spade or ring terminal. Make
sure that the screw doesn’t come in contact with
anything that is revolving inside like the advance

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weights when they are fully advanced. The point
plate also moves and must be free of anything that
could bind it. The screw must be flush with the
inside of the bowl. Another option would be to put
a clamp on the lower shank area of the housing.
The distributor clamp is not a reliable ground.

5. Make sure that the block is also grounded to
the frame.

MECHANICAL ISSUES
EFFECTING DISTRIBUTORS

IF THE TIMING IS ALL OVER THE PLACE WHEN
CHECKED WITH A TIMING LIGHT

1. First check for excessive wear in the gears. Grab
the rotor and turn it back and forth. If it has
excessive play, check for wear on both the
camshaft and the distributor.

2. If the gears appear normal, use a socket and a

breaker bar to gently rotate the crankshaft back and
forth. The key here is to see how far the crank
rotates before the rotor moves. Anything beyond a
few degrees indicates a worn timing chain/gear
assembly that needs to be replaced.

3. Check the advance. The simple way to evaluate
the advance is simply grab the rotor and turn it.
This will activate the mechanical advance and give
some indication if there is a problem in the
distributor. If you can turn it one way against the
springs and it snaps back to the original position
when it is released, it is fine.

1. If it binds, the advance is suspect and
needs to be checked.

2. If it turns but does not come back to the
rest position, the springs have probably
either come off or are broken.

IF THE POINTS ARE CONTINUALLY OUT OF
ADJUSTMENT

1. Check the upper end of the shaft for excessive side
to side movement. Lateral movement will cause
the points to require constant adjustment. The only
solution is to replace or rebuild the distributor.

2. Confirm that the point set is not designed for racing
only with excessive spring tension. This increases
rubbing block wear even with properly lubricated.

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(LEGAL IN CALIFORNIA ONLY FOR RACING VEHICLES WHICH MAY NEVER BE OPERATED UPON A HIGHWAY)

INSTALLATION PROCEDURE

Step 1

Locate the spark plug wire on the original distributor cap that the engine timing is set
from. (See service manual for these locations.)

Step 2

Remove the distributor cap. Do not remove the plug wires or coil wire at this
time.

Step 3

Turn the engine crankshaft in the direction of rotation until the timing mark lines up with
the top dead center (TDC) mark on the timing tab (See a service manual for these
locations). NOTE: Once this step is finished, DO NOT turn the crankshaft until the

new distributor is installed.

Step 4

Remove distributor primary wire connected from distributor to negative terminal of coil. If
original distributor is a vacuum advance unit, note the direction that the vacuum chamber
is pointing and remove the vacuum line. Remove the original distributor.

Step 5

Remove cap from Mallory distributor. If a vacuum advance unit is being replaced, turn
the Mallory distributor so that the vacuum chamber is pointed in the same direction as
the original. If the original had had no vacuum advance, and is being replaced by a
Mallory vacuum advance unit, point the vacuum chamber so that there is room to turn
the distributor for timing adjustment. In all cases, line up the rotor so that it points in the
same direction as the original, and install it in the engine block. Be sure that the
distributor is seated in the block.

Step 6

Rotate distributor body in opposite direction of rotor rotation until points just open.
Tighten holding clamp so distributor body will not move. Place a mark on distributor body
in line with the rotor blade center.

Step 7

Reinstall distributor cap. The spark plug wire tower of the cap which lines up with the
mark on the distributor body is now designated No. 1 cylinder. Remove No. 1 cylinder
spark plug wire from original cap and place in No. 1 tower on the Mallory distributor cap.
Remove spark plug wires, one at a time, from the original cap and install in Mallory cap
in the same rotation and sequence as they were removed from the original cap. Remove
coil wire from original cap. Install this wire in the Mallory cap.

Step 8

Connect primary wire from negative terminal of coil to the distributor terminal.

Step 9

If installing a non-vacuum distributor, skip to step 10. For vacuum advance units, locate
the original vacuum line. If none is present, a line must be run to a ported vacuum
source. Do not connect this until after the engine has been timed. Temporarily plug this
line.

Step 10

CAUTION: For the following procedures make sure that you and all of the wires
for the timing light are clear of moving engine parts, such as the fan and any
belts, power steering pumps, etc.

Connect a timing light. Install the distributor clamp and tighten it just
enough so the distributor can be rotated for timing purposes. Start the
engine and rotate the distributor so that the timing is as recommended
by the manufacturer. Tighten the distributor clamp and make sure that
timing is still correct. If not, repeat step 10.

Step 11

If a vacuum advance distributor is installed, remove the temporary plug from the vacuum
line and connect it to the vacuum chamber.

GENERAL SERVICE INFORMATION

Lubrication

(Every 50 hours) apply a light film of grease on the cam lobes. Apply chassis lubricant
with a hand gun to tach drive grease fitting. (Stop at the slightest back pressure.)

Centrifugal Advance

Springs are adjustable by using a screw driver in the circuit breaker plate holes. DO NOT
DAMAGE the spring loops. If necessary, disassemble, place a light film of grease at the
upper shaft and a light film of oil on all other parts.

Tachometer Drive Assembly

Use a suitable wrench and disassemble tach drive assembly. Clean all parts and inspect
for wear. Reassemble, lubricating all parts with hand gun.

Coil Check

Remove the coil output wire from the distributor cap. Hold this wire about 1/2" away from
ground. Crank engine with the ignition key on. A reasonable snappy blue spark should
be obtained. If spark output is weak, check secondary wiring, and all wiring and
connections in the primary circuit. If these parts are okay, remove coil for testing.

Distributor Cap

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To test for a secondary breakdown, position the cap so that the inner segments can be
seen. Turn ignition key on and crank the engine. The high voltage entering in the cap
from the coil will arc across any portion that may be defective. If the cap is free from
defects, check the seating of each spark plug wire and clean all surfaces.

Rotor

Point Adjustment

Adjust the breaker points as shown in the table below for appropriate model distributor
you have installed.

CAUTION: In models with the triangular hole in the breaker plate,
exercise care in using a screwdriver to adjust the setting, as it is
possible to extend the screwdriver blade far enough to damage the

To test, remove the distributor cap. Remove the coil wire that leads into the cap. Hold this
coil wire one-half inch above the rotor. Crank the engine with the key on; no sparks
should be obtained. If the rotor is defective, the high voltage spark will pinpoint the exact
location of the defect. Replace if necessary.

DP CURVE

All dual point distributors that end in 01 have 24° @ 3000 RPM Except:
2301105 18° @ 2000 RPM 2362901 24° @ 4000 RPM
2301106 14° @ 2500 RPM 2363301 28° @ 3000 RPM
2527501 16° @ 3600 RPM 2364001 28° @ 4600 RPM
2354109 22° @ 2500 RPM 2368301 28° @ 3000 RPM
2557901 20° @ 3000 RPM 2768902 18° @ 3400 RPM

MALLORY TUNE-UP PARTS 25 AND 26 SERIES 27 SERIES CONTACT POINT ADJUSTMENT
8 CYLINDER MECH. ADVANCE VAC. ADVANCE DUAL POINT SINGLE POINT

DISTRIBUTOR CAP 209 209

ROTOR 309 310 POINT GAP, .022" POINT GAP .018"

HIGH ENERGY DISTRIBUTOR CAP 208* 208**

HIGH ENERGY ROTOR 308 307

PERFORMANCE POINTS 25042X

STANDARD POINTS 25042 157 DWELL (EA.) 26° DWELL 29°

CONDENSER 400 401

DUAL POINT KIT (STD.) 29315 29405

DUAL POINT/CONDENSER KIT (STD.) 29320 29406

TUNE-UP KIT 570  TL DWELL 33

VACUUM ADVANCE CHAMBER  29332

* MUST BE BRACKET KIT PART NO. 29316 ** MUST USE BRACKET KIT PART NO. 29317

+_

2°

MALLORY TUNE-UP PARTS 23 AND 24 SERIES 25 AND 26 SERIES CONTACT POINT ADJUSTMENT
6 CYLINDER MECH. ADVANCE MECH. ADVANCE VAC. ADVANCE DUAL POINT SINGLE POINT

DISTRIBUTOR CAP 270 209 209 POINT GAP .028" POINT GAP .022"

ROTOR 309 320 310

PERFORMANCE POINTS 25042X 25042X  DWELL (EA.) 29° DWELL 31°

STANDARD POINTS 25042 25042 157

CONDENSER 400 400 401 TL DWELL 41

VACUUM ADVANCE CHAMBER   29332

POINT IGNITION: 23 SERIES

SEMI-EVEN AND ODD-FIRE V6 23 SERIES CONTACT POINT ADJUSTMENT

DISTRIBUTOR CAP 270 POINT GAP .022"

ROTOR 310

PERFORMANCE POINTS 25042X INDIVIDUAL DWELL 30°

STANDARD POINTS 25042

CONDENSER 400 TL DWELL 35

MALLORY TUNE-UP PARTS 23 AND 24 SERIES 25 AND 26 SERIES 27 CONTACT POINT ADJUSTMENT
4 CYLINDER MECH. ADVANCE MECH. ADVANCE VAC. ADVANCE DUAL POINT SINGLE POINT

DISTRIBUTOR CAP 271 225 271 POINT GAP .022" POINT GAP .018"

ROTOR 309 320 310

PERFORMANCE POINTS 25042X 25042X  DWELL (EA.) 32° DWELL 34°

STANDARD POINTS 25042 25042 157

CONDENSER 400 400 401 TL DWELL 41

VACUUM ADVANCE CHAMBER   29332

+_

2°

+_

2° TL DWELL 34

+_

2° TL DWELL 34

+_

+_

2°

2°

ADJUSTMENT PROCEDURE

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ADJUSTMENT

SCREW

ADJUSTMENT PLATE

(ON BOTTOM)

LEFT HAND

ROTATION

SPRING PERCH

ADVANCE TAB

RIGHT HAND

ROTATION

ADJUSTMENT

SCREW

ADJUSTMENT PLATE

(ON BOTTOM)

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