How to Tune up an Older Car
Obtain information about ignition point gaps, firing order, timing advance and spark plug gaps from the car manual or other reliable source., Buy replacement spark plugs, ignition points, ignition leads, condensers as needed., Start with a clean...
Step-by-Step Guide
-
Step 1: Obtain information about ignition point gaps
Mostly these will not be required, though it is best to replace the ignition points. , If the spark plug leads are not already numbered, use a marker to do so.
This can be wiped off later if you like.
No.1 cylinder is at the front of the car.
With transverse motors No.1 cylinder is nearest the radiator. ,, This prevents damage to the connector.
Do not bend the leads sharply as this can wreck the carbon based inner conductor. ,, If the electrodes are severely rounded off or the insulators are damaged, do not re-use. ,, Do not attempt to adjust the centre electrode.
Bend the outside one with pliers to open, tap gently on a firm surface to close.
A firm sliding fit with the gauge square to the plug shows the correct gap. , You will see a central shaft with a Bakelite rotor above it.
This rotor points to the appropriate contact on the inside of the cap as each spark plug fires.
Lift the rotor off, be careful that small parts do not drop off.
Wipe the contact areas of the rotor with a coarse rag or one stroke along the edge of a matchbox, no more. , If there are carbon tracks or cracks, replace the cap.
Otherwise wipe clean, remove deposits from the electrodes and set aside. , Note that one can be used to set the gap, the other holds the points in place.
A wire from the outside of the distributor connects to the condenser and the ignition switch. ,, Slight pitting is normal and may be dressed off square with a file.
The points may then be re-used. , This often comes with a new set of points.
Wheel bearing grease may be used.
Do not use oil, ordinary grease or petroleum jelly as the spinning shaft will throw the lubricant off and it can get between the points. , Give them a gentle poke with a screwdriver to ensure they have not jammed up.
There may be a hole marked "Oil" to lubricate them.
Two drops of engine oil is enough.
Wipe up any oil spillage. , Put the screws in firmly but do not fully tighten them yet. , Use a wrench/spanner on the hexagon at the bottom pulley. , Place in the gap of the points and tighten the points screws.
You will almost certainly not get the gap correct the first time so repeat until the gap is correct. , The rotor cap must be pointing to the position of the No. 1 plug lead.
This may take more than one full rotation of the engine as the distributor shaft rotates at half the engine speed. , This should be shortly before the piston reaches top dead centre.
The advance is measured in degrees and is usually around 8 to
15.
The bottom pulley may have two marks with a single mark on the motor front.
The first of these marks is the correct one, the second corresponds to top dead centre.
Match the mark on the pulley with that on the engine. , Select the correct mark on the engine and match it up with the mark on the pulley.
From the front of the engine this will be clockwise of the mark for top dead centre. , Alternately use the vernier adjustment if fitted. , Be sure the spark plugs are out of the engine.
Switch on the ignition but do not crank the engine. , With the points open, it will glow brightly. , Switch off the ignition and tighten the distributor without moving it. , If the distributor baseplate moves, the vacuum advance is working adequately.
Reconnect the tube.
If the tube is holed, replace it. , Burnt-looking connectors indicate loose connections.
Replace the lead or take off the connector, clean, cut 2cm or 3/4 inch of lead away and replace the connector.
Wipe the leads clean of dirt and oil. , Carefully thread the spark plugs in, hand tighten then a twitch with a wrench is all that is needed. , If it does not start, have you replaced the rotor cap? , -
Step 2: firing order
-
Step 3: timing advance and spark plug gaps from the car manual or other reliable source.
-
Step 4: Buy replacement spark plugs
-
Step 5: ignition points
-
Step 6: ignition leads
-
Step 7: condensers as needed.
-
Step 8: Start with a clean engine.
-
Step 9: Note where the No.1 lead enters the distributor cap.
-
Step 10: Grasp each spark plug lead at the plug end as close to the motor as you can get and pull straight out.
-
Step 11: Use a proper spark plug wrench to loosen every spark plug and remove them.
-
Step 12: Check the spark plugs.
-
Step 13: Scrub the plugs with a wire brush and rinse with gasoline/petrol or kerosene and set to dry if you wish to re-use.
-
Step 14: Set a feeler gauge to the required gap and place between the centre electrode and the side one.
-
Step 15: Remove the distributor cap.
-
Step 16: Inspect the interior of the distributor cap for dirt
-
Step 17: cracks
-
Step 18: moisture and carbon tracks.
-
Step 19: The ignition points will be held in with two screws.
-
Step 20: Remove the ignition points
-
Step 21: being careful to note the position and number of any insulating and other washers fitted.
-
Step 22: Inspect the points for pitting and deposits.
-
Step 23: Pack the angle where the points assembly slides over the cam on the distributor shaft (the follower) with a little blob of high temperature grease.
-
Step 24: Look for the centrifugal ignition advance weights which may be partially visible below the baseplate.
-
Step 25: Replace the points on the baseplate with washers in the correct places.
-
Step 26: Rotate the engine clockwise with the spark plugs out and the transmission in neutral (looking from the engine rear)so that the follower is at the top of a shaft cam lobe.
-
Step 27: Set a feeler gauge to the correct points gap and wipe it so that it is free of dirt and oil.
-
Step 28: Replace the rotor cap and rotate the engine clockwise until the timing marks on the bottom pulley are opposite the marks on the front of the engine.
-
Step 29: The spark plug fires as the points just begin to open.
-
Step 30: Alternately there is one mark on the pulley and two or more marks on the engine.
-
Step 31: Loosen the distributor at the fitting on the shaft below the body.
-
Step 32: Connect a 12 Volt trouble light to a good ground and to the terminal outside the distributor where the condenser connects.
-
Step 33: While the points are closed
-
Step 34: the lamp will be out or glowing dimly.
-
Step 35: With the rotor cap pointing to No.1 position
-
Step 36: rotate the distributor slightly or use the vernier so that the lamp just lights.
-
Step 37: Disconnect the tube to the vacuum advance diaphragm from the fuel system and suck on the tube.
-
Step 38: Inspect the spark plug leads.
-
Step 39: Replace the spark plugs
-
Step 40: distributor cap and plug leads in the correct order.
-
Step 41: Start the engine.
-
Step 42: Have you replaced the rotor?
Detailed Guide
Mostly these will not be required, though it is best to replace the ignition points. , If the spark plug leads are not already numbered, use a marker to do so.
This can be wiped off later if you like.
No.1 cylinder is at the front of the car.
With transverse motors No.1 cylinder is nearest the radiator. ,, This prevents damage to the connector.
Do not bend the leads sharply as this can wreck the carbon based inner conductor. ,, If the electrodes are severely rounded off or the insulators are damaged, do not re-use. ,, Do not attempt to adjust the centre electrode.
Bend the outside one with pliers to open, tap gently on a firm surface to close.
A firm sliding fit with the gauge square to the plug shows the correct gap. , You will see a central shaft with a Bakelite rotor above it.
This rotor points to the appropriate contact on the inside of the cap as each spark plug fires.
Lift the rotor off, be careful that small parts do not drop off.
Wipe the contact areas of the rotor with a coarse rag or one stroke along the edge of a matchbox, no more. , If there are carbon tracks or cracks, replace the cap.
Otherwise wipe clean, remove deposits from the electrodes and set aside. , Note that one can be used to set the gap, the other holds the points in place.
A wire from the outside of the distributor connects to the condenser and the ignition switch. ,, Slight pitting is normal and may be dressed off square with a file.
The points may then be re-used. , This often comes with a new set of points.
Wheel bearing grease may be used.
Do not use oil, ordinary grease or petroleum jelly as the spinning shaft will throw the lubricant off and it can get between the points. , Give them a gentle poke with a screwdriver to ensure they have not jammed up.
There may be a hole marked "Oil" to lubricate them.
Two drops of engine oil is enough.
Wipe up any oil spillage. , Put the screws in firmly but do not fully tighten them yet. , Use a wrench/spanner on the hexagon at the bottom pulley. , Place in the gap of the points and tighten the points screws.
You will almost certainly not get the gap correct the first time so repeat until the gap is correct. , The rotor cap must be pointing to the position of the No. 1 plug lead.
This may take more than one full rotation of the engine as the distributor shaft rotates at half the engine speed. , This should be shortly before the piston reaches top dead centre.
The advance is measured in degrees and is usually around 8 to
15.
The bottom pulley may have two marks with a single mark on the motor front.
The first of these marks is the correct one, the second corresponds to top dead centre.
Match the mark on the pulley with that on the engine. , Select the correct mark on the engine and match it up with the mark on the pulley.
From the front of the engine this will be clockwise of the mark for top dead centre. , Alternately use the vernier adjustment if fitted. , Be sure the spark plugs are out of the engine.
Switch on the ignition but do not crank the engine. , With the points open, it will glow brightly. , Switch off the ignition and tighten the distributor without moving it. , If the distributor baseplate moves, the vacuum advance is working adequately.
Reconnect the tube.
If the tube is holed, replace it. , Burnt-looking connectors indicate loose connections.
Replace the lead or take off the connector, clean, cut 2cm or 3/4 inch of lead away and replace the connector.
Wipe the leads clean of dirt and oil. , Carefully thread the spark plugs in, hand tighten then a twitch with a wrench is all that is needed. , If it does not start, have you replaced the rotor cap? ,
About the Author
Melissa Armstrong
A passionate writer with expertise in practical skills topics. Loves sharing practical knowledge.
Rate This Guide
How helpful was this guide? Click to rate: