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How To Tune Up Your 199, 232, or 258 Six With Points Type
One of the things you need to do periodically is tune up your car. The
work involved is pretty easy but there is an order you have to follow or
you'll never get the car tuned correctly. You should also be aware that a
proper tune up can take several hours (or longer) to perform.
Here is a list of the tools you'll need to do this job:
- Compression test gauge
- Dwell meter
- Tachometer (don't rely on factory gauges for this, they are
frequently not accurate or sensitive enough).
- Vacuum pump
- Flat head and Philips screw drivers
- Spark plug socket and socket wrench
- Points file
- Feeler gauges
- 1/2" box or open end wrench
- Tune up specifications for your car. These can generally be found in
your owner's manual, your shop manual, or on the emissions sticker (1968
- Other hand tools such as pliers and wrenches to disconnect
and fuel lines.
There are two types of tune ups that you'll need to do depending upon the
mileage since the last tune up and how poorly the car is running. The first
type is a minor tune up which involves visually inspection of the fuel and
ignition systems and minor repairs such as replacing filters or ignition
system parts (points, cap and rotor, plugs, etc...). The second type is a
major tune up which will also involve rebuilding the carburetor (here
is how to rebuild a Holley model 1931). I typically
do a major tune up when I first get a vehicle and then yearly minor tune
ups. If you drive your car year round, you'll likely need to do minor tune
ups twice a year (spring and fall) to keep the car at it's peak performance.
Regardless of which type of tune up you'll be doing, you need to start
with making sure that the engine is in good mechanical condition. To do
that, you'll need a compression test gauge. To check the engine's
compression do the following:
- Make sure the battery is fully charged and the cables are clean,
tight, and in good condition. This will ensure that you don't get false
readings from a weak starting system.
- Disconnect the coil power wire from the coil. This is the yellow
wire connected to the + terminal on the coil. The - terminal should have
a wire going to the distributor, if the wire are improperly connected,
fix that now since this will cause the car to run poorly.
- Number the spark plug wires so you can tell where they go. The #1
cylinder is the one at the front of the engine.
- Remove the spark plugs. As you remove them, take a few moments to
inspect them. If there are hard black deposits on them, the engine is
burning oil. Softer black deposits (sooty looking) are caused by a rich
fuel mixture or other carburetor problems.
- Remove the air cleaner assembly and block the throttle and choke
plates fully open.
- Connect the test gauge to each cylinder and crank the engine. You
want the engine to make several revolutions (at least 4) until the
maximum pressure is reached. Write down the max pressure for each
cylinder. The normal pressure is around 145 PSI but the more important
indication is how balanced all of the cylinders are. The cylinders
should be within 10 PSI of each other. If two adjacent cylinders are low
and of equal pressure, that indicates a blown head gasket. If all
cylinders read low (under 120 PSI), the cylinder bores are worn and the
engine needs to be rebuilt. Note: If the engine has
been sitting for a long time, you may have low cylinder pressure until
the car has been driven a few hundred miles since the rings may be stuck
or slightly damaged from rust. It is okay to proceed with the tune up in
this case. Using a top engine cleaner prior to tuning the car up will
help in loosening the rings up.
Once you've verified that the engine is in good mechanical condition, it
is time to do the actual tune up.
- Remove the distributor cap and set it aside.
- Gently twist the rotor. It should move slightly and snap back into
place. If it doesn't move or doesn't snap back into position when you
release the rotor, the mechanical advance is sticking or seized. You
will need to remove the distributor to fix this.
- Disconnect the vacuum advance vacuum hose. Inspect the hose for
cracks or softness and replace as needed. Plug the hose it with a
sharpened #2 pencil or golf tee.
- Connect a vacuum pump to the vacuum advance can and apply vacuum to
it. The points should rotate slightly when vacuum is applied and it
should hold the vacuum. If the points don't move, you'll need to remove
the breaker plate for further inspection. If the vacuum advance doesn't
hold vacuum, it must be replaced.
- Remove the rotor and set it aside.
- Inspect the cam lobes for excessive wear (grooves on some or all of
the lobes, or flattened lobes). If the lobes are damaged, you will need
to replace the distributor.
- Remove the felt disc under the rotor, lightly oil it with engine
oil, and return it to its proper spot. It should be wet but not
dripping. If the felt was very dry, you may need to oil it several times
to fully saturate it. If you get it dripping wet, gently squeeze it in a
shop towel to remove the excess oil.
- Inspect the points for burning and large material transfer (more
than .020"). These problems generally indicate a failed condenser. You
will need to replace the points and condenser if you find this
condition. If the contact material on the points is mostly gone, you
will also need to replace the points and condenser. If you are not
replacing the points and condenser, gently file the points smooth if
needed. Note: some material transfer between the
contacts is normal and actually desirable. Inspect the point set to make
sure the contacts are aligned with each other. Correct the alignment or
replace the points and condenser as needed.
- If you replaced the points, mark the distributor location on the
engine block (chalk works well for this), loosen the distributor hold
down clamp and rotate the distributor until the rubbing block on the
points is on the high spot on the cam. Set the point gap to .016".
Rotate the distributor to its previous position and tighten the hold
down clamp. If you didn't mark the location of the distributor, set the
hose nipple on the vacuum advance can so it is parallel to the engine
- Inspect the rotor for burning, cracking, and excessive wear. Replace
- Inspect the distributor cap for cracking, burned or pitted contact,
and carbon tracking. Replace as needed.
How To Line Up Your Distributor
If you had to remove the distributor or it is not
properly installed already, here is the procedure I follow to
properly reinstall it. If the
distributor is in the car already, start with step 1. If it is out,
start with step 6.
Here is how to do
- Disconnect the power wire to the coil.
- Remove the air cleaner
assembly (this prevents a back fire from setting your air filter on fire).
- Pull the #1 spark plug, put your finger near the plug hole, and "bump" the
engine over until you feel pressure on your finger followed by suction (this
is the point where the engine is just past TDC).
- Line the mark in the
balancer with the zero mark on the timing pointer (this puts you at TDC on
the #1 cylinder).
- Remove the distributor cap.
- The rotor should be
pointing towards the radiator and parallel to the engine and the vacuum
advance canister should also be parallel to the engine. Here is what a
properly installed distributor looks like:
If these are not parallel, you need to remove the
distributor and line it up properly. You may need to use a long and thick
flat blade screwdriver to turn the oil pump drive shaft. This would be a
good time to oil the felt underl the rotor with engine oil. It should be wet
but not dripping.
- Once it is lined up, connect a continuity tester (or a
self-powered test light) to the - terminal on the coil and ground. Rotate
the distributor until the point open (continuity tested shows an open
circuit or light goes out). Tighten the distributor. This will get the
timing pretty close to TDC which will allow the engine to start.
- Re-install the distributor cap and make sure the plug wires are connected
properly. The #1 terminal on the cap is the one next to the vacuum advance
can on the engine side.
- Re-connect the coil power wire.
point, the engine will either start up or back-fire through carburetor. If
it back-fires, the distributor is 180 degrees out. You can either move the
plug wires on the cap or pull the distributor back out and turn it 180
degrees. The engine will not care either way but it is best to rotate the
Spark Plugs, Wires, and Ignition Coil
- Inspect the spark plugs for damage (cracked insulators, damaged
contacts, etc...) and clean or replace as needed. Set plug gap to .035"
and install the spark plugs. Note: Use of platinum
tipped spark plugs is not recommended for points style ignition systems.
They do not provide enough spark energy to fire these types of plugs
- Inspect the ignition wires for damaged boots or insulation. Make
sure to flex the entire wire into a U shape and inspect for cracks on
the outside of the U. Damaged wires must be replaced. Once the visual
inspection is completed, check the resistance with the ohmmeter. The
coil to cap wire should be 7,500 to 12,000 ohms per foot and the cap to
plug wires should be 3,000 to 7,000 ohms per foot. Replace any wires that
fail this test.
- Install the spark plug to cap wires making sure that they snap into
place. If any of the wires do not snap into place, you must fix the
problem or you will have a misfiring cylinder.
- Inspect the coil for physical damage (rust outs, loose terminals,
breaks in the coil wire tower or top of the coil) and replace if needed.
The ignition coil is oil filled so any oil staining on it may indicate
it is leaking. A valve cover leak can also make oil stains on the coil
so you will need to remove the coil and inspect it further.
Note: Depending upon the model and year car you are working on,
the coil will have either an internal resistor or an external resistance
wire. If you have to replace the coil, make sure you get the proper
- Ensure that the power wire is connected to the + terminal and the -
terminal is connect to the distributor. Correct as needed.
- Install the coil to distributor cap wire.
Ignition System Adjustments
- Clean the timing pointer on the engine and mark the notch on the
- Start the car and allow it to warm up. Once it is warm enough to run
at normal idle, check the point dwell. It should be between 31 and 34
degrees. A wider point setting reduces the dwell angle and a narrower
point gap will increase it.
- Set the idle speed to 500 RPM or less (you may need to back out the
fast idle screw to do this).
- Adjust the timing to the specification. You can find this in the
owners manual, in the service manual, or on the emissions sticker (1968
and newer cars).
- Reconnect the vacuum advance hose.
- Adjust the idle speed to 550 RPM in drive for automatics or neutral
for manual transmissions.
- Shut off the engine.
- Remove the air filter and clean or replace as needed.
- Remove the PCV filter from the molded hose leading to the valve
cover. Clean with solvent and lightly oil with 20 weight oil.
- Reinstall the air cleaner assembly,
- Remove the PCV valve from the valve cover and start the engine.
Place your finger over the end of the valve. You should feel a vacuum
and then the valve should snap shut. Replace if it fails this test.
- Restart the engine and allow it to reach normal operating
- Adjust the fuel mixture as outlined below:
- Slowly back out the fuel mixture screw until engine speed drops
- Slowly turn the screw in until max engine speed is reached and
continue turning it in until the speed drops off again.
- Slowly turn the screw out again until the max engine speed is
- If there is more than a 50 RPM change in speed from where you
started at, repeat the procedure.
- Set the curb idle speed to the specification. Generally, that is 525
RPM in drive for automatics and 600 RPM in neutral for manual
- Adjust the fast idle speed to specifications.
09/25/10 10:21:29 PM