Ill use the term VOM to denote volt/ohm/amp/meter.
STARTERS:
The starter current draw on a Ford V-8 through 1948 is 550 amps
(does not include V-8 60s) . The starter cranks a stock
flathead engine at 100 rpms. The 1949 - 1951 engines crank 130
rpm (without an automatic transmission)
GENERATOR DOES NOT CHARGE:
Two brush Ford generators use the shunt type generator design.
The field circuit has an internally grounded field. ... unlike
MoPar and GM which ground through the regulator. To test a Ford
generator and/or regulator on the car, simply ground the field
terminal at either the generator or regulator with the engine
turning about 1000 rpm and watch the amp gauge (do not disconnect
any wires) . Grounding the field removes all external regulation
on the generator and it will go immediately to full charge mode.
If the ammeter shows charge when you ground the field, the regulator
is at fault. If the ammeter does not show charge, the generator
is defective. Note the generator may have shorted out the regulator
when it went bad.
Since the 6 volt regulators are still mechanical and can be set,
it may be beneficial to know what is where inside them.
POLARIZING A 2 BRUSH FORD GENERATOR:
Disconnect the FIELD terminal wire at the regulator and momentarily
touch this wire to the BAT terminal of the regulator. NEVER use
a jumper wire to keep from disconnecting the fieldwire at the
regulator itll ruin the regulator in a hurry.
The field wire MUST be disconnected from the regulator. MoPar
and GM generators are not polarized in this manner due to their
different design.
DIM LIGHTS:
Dim lights are usually caused by low voltage to the lightor by
a weak ground. Naturally the battery has to be charged with good
clean posts. The wires in a 6 volt system are considerably larger
than in a 12 volt system. Be certain that any wiring youve
done is at LEAST as big as what your Ford came with to keep from
choking the system.Usually the culprit is in the ground.... or
rather the lack of.
The 6 volt battery should have the positive battery cable connected
directly to the frame. Naturally the frame under the cable needs
to be scraped bare and bright to function as a good ground. Make
certain the frame and body are grounded by bolting a ground strap
between them. Next thing is to make sure the bulb socket has a
good ground between it and the frame. Clean the inside of thesocket
with some steel wool or sand paper until its shiny and bright.
Many of these sockets are pressed into the reflector and this
electrical union begins to fail electrically over the years. When
in doubt, solder a length of wire to the brass socket itself and
temporarily ground it directly to the frame. If this cures the
dim light, youll know exactly where the problem lies and
whatsneeded to correct it.
If youre running the stock 6 volt head light bulbs and theyre
something in the neighborhood of 25 watts, replace them with some
50/32 bulbs. It does wonders for them. Berts Model A Center
has these in stock.
Sometimes you have a bulb that is not burned out, but refuses
to work in the socket. Could be the contacts are worn down too
much. Just drop a little solder on these and they 11 work
like new.
ELECTRICAL TERMINATIONS:
Im always amazed at the number of these I find that are
bad. We go to great lengths to cut the wire exactly the right
length and to trim back the insulation just the right amount and
crimp the new terminals neatly. These terminations usually function
perfectly for sometime and then the electrics start giving troubles.
After much frustration and messing around, we may finally get
them to start working again. More often than not, they soon start
acting up again.Many times I finally track the problem down to
the crimped termination itself. At first the newly crimp works
and current flows. Eventuallyoxidation starts and the resultant
insulating occurs. The result is the crimped terminal becomes
partially insulated between the wire and the terminal. Sometimes
the crimp itself relaxes its hold due to heat and compression
and the conductor becomes loose in the termination. To keep this
from happening, I trim back about 1/16 more insulation than
is needed. I push the bare wire clear through insulated part of
the termination so that it extends 1/16 beyond it. Then,
after I have crimped the insulated part of the terminal, I solder
the 1/16 bare conductor solidly to the electrical terminal.
Now it cant getloose or become insulated by oxidation. Ive
never had one fail when doing it this way. I solder all electrical
connections.
As far as using the insulated crimp type splice connectors to
splice two wires, I will not use them under any circumstance....
I just dont trust them since Ive seen some burned
up wiring caused by the wires pulling free of the splicing connector.
I bare the two wires and do not twist them separately or together.
Instead I push them straight into each other so the wires are
intermixed with each other. After smoothing them out and squeezing
them with pliers, I flow solder into this mix to make the splice
permanent. I finish by using heat shrink tubing to cover the newly
soldered splice. A trick I use here is to squeeze the soldered
connection with pliers while its still warm to reduce any
blobs or peaks of solder so the heat shrink tubing will slide
over the splice easily.As far as male bullet connectors
used in most early cars, Ive always had trouble crimping
them enough to hold them and still have them fit into the round
female connector. I remove the insulated material from the bullet
connector (grind a slot along one edge of the insulating area
with the edge of the bench grinder and the insulation will pull
right off). Then I bare the conductor just enough so the wire
will just barely go all the way into the bullet. I flow solder
into the bare bullet connector without ever crimping it After
its cooled, I slide some heat shrink tubing onto the bottom
of the bullet and shrink it with a match.
Another thing I do is make all my battery cables. Seems the ones
I purchase are always the wrong length, usually the wrong color,
and Im unsure as to how good they crimped the connectors
onto the cables. I watch for long cables at the flea market and
at swap meets. I use battery/starter terminations from my local
parts store. I cut the cable to the exact length I want. Then
I strip back the insulation, install and solder the new terminations
to the cables. I finish them by using heat shrink tubing (sometimes
two layers)
DISTRIBUTOR VACUUM ADVANCE: The 1948 and earlier Ford engines have a
different type of vacuum advance than we normally encounter. Intake
manifold vacuum is routed to an internal brake inside the distributor.
The amount of brake thats applied to the centrifugal weight advance mechanism
controls the degrees of advance. When vacuum drops, the brake spring overcomes
the vacuum that is holding the brake away from rubbing against the centrifugal
advance mechanism. The more spring tension there is being exerted against
this brake,the sooner the brake is activated and the sooner the centrifugal
advance mechanism is stopped thereby controlling the amount of advance.
To increase the spring tension and decrease the amount of centrifugal
advance,turn the advance screw inwards. To decrease the spring tension
and increase the amount of centrifugal advance, turn the advance screw outwards.
The vacuum advance screw is used to eliminate detonation.
To adjust initial (static) advance, loosen the lock screw on the
side of the distributor and move the advance screw/plate up or down. As viewed
from the front of the engine, moving the advance screw & plate clockwise
advances the timing.
SETTING STATIC TIMING ON 42-48 V-8 DISTRIBUTORS:
Stock Ford specifications call for the initial (or static) timing to be set
at 4 degrees BTDC (Before Top Dead Center) . This is best set on a distributor
machine. In the absence of one, it can be set using common tools. The following
is from a Ford service bulletin for 42-48 distributors.
[1] Remove the distributor and adjust both sets of points to
0.014. Loosen the vacuum brake screw lock nut and back the screw out several
turns. Loosen the advance screw/plate screw on the side of the distributor and
verify it moves up and down fairly easily. We have to move this advance
screw/plate to set the timing, so we need it to move easily.
[2] Connect up a continuity test light. Connect one lead of the
test light to the screw stud the wire from the coil is connected to. The other
test lead isgrounded to the distributor housing.
[3] Now turn the distributor upside down so youre looking at the back of it.
Notice how the distributor drive has a wide side and the tang is offset? Turn
the distributor drive so the wide side is towards the condenser.
Position a straight edge on this wide side (holding it snug up against the
tang) in such a way that the straight edge extends to the outside of the drivers
side of the distributor housing. Rotate the distributor drive and straight
edge until there is exactly 3/8 from the top of the drivers side
distributor mounting hole to the straight edge. This is 4 degrees BTDC. Holding the
distributor drive and distributor firmly so they cannot move, slide the advance
screw/plate up and down until the continuity light just flickers. This is when the left
set of points are just breaking open and is when the distributor
fires. Tighten the advance screw/plate. In Denver, I just adjust the vacuum brake adjuster
out until the engine pings (detonation) under 35-40 mph high gear acceleration and then turn
it back in one-half turn. This adjusts for altitude as well as the type of fuel wereusing.
The vacuum controlled centrifugal weights should be adjusted to be 25 to 28 degrees at 2000 rpm
at sea level.
DETONATION: Detonation is the uncontrolled burning of fuel during combustion. It can lead to pre-ignition, running on,burned pistons, cracked piston skirts, and deform piston ring grooves/lands. Sometimes its hard to detect light detonation while driving due to road noise etc.. However,detonation will leave its mark in the spark plugs. This appears as a dark ring around the porcelain on the inside of the plug. If a detonation ring is present, retard the spark or possibly go to a colder plug or possibly increase the main jet size or increase the octane of the fuel youreusing... . or do a mixture of them all! If your compression is really high like mine, I have to ad an octane enhancer when I go down to a lower altitude. My 9.95:1 compression really sounds off when I get near sea level!!!!!!
COIL CONNECTIONS:
On a positive ground system, the feed from the ignition switch is to connect
to the negative marked terminal on the coil. If connected wrong, the coil output will be about
14% less at idle. This percent of reduced coil output increases to as much as 30% as rpms
increase. The decreased coil output causes hard starting and poor performance.
COIL TESTING USING OHMS:
Coils can be checked using the Ohm function of a VOM. To measure
primary resistance, connect one lead to the ignition terminal of the coil and the other to the
distributor terminal of the coil. The resistance should be between 0.7 and 0.8 Ohms.
To measure the secondary resistance, connect one lead to either the distributor or ignition
terminal of the coil and the other lead is inserted into the high tension tower. It must
make contact with the metal inside. The resistance should be 6500
to 7500 Ohms. If either measurement falls outside these values, the coil is probably
on its way to being junk or has already arrived. These ohm values are only for genuine
Ford coils since each manufacturer has different values for their product. This is not a fail
safe test, but Ive used this for years as a guide for coils with good results. Its
especially quick and easy for use at a swap meet.