How Do I Tune-Up My 1978 Triumph Spitfire?

Written by tim petruccio
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How Do I Tune-Up My 1978 Triumph Spitfire?
(uk flag image by kolesn from

Performing a basic tune up your 1978 Triumph Spitfire will ensure that it is running at its peak performance. The 78 Spitfire comes equipped with a 1.5 litre, 1 barrel, overhead valve engine. The way these vehicles were designed is a true tribute to British engineering and makes for easy tuning of the engine. The tune up should take no more than three hours, even if you have never worked on your Spitfire. The main focus of a tune up is to ensure that the car is getting the correct fuel to air ratio, as well as a proper ignition spark. All parts for this job should be available at your local parts store.

Skill level:

Things you need

  • Air filter
  • 4 Spark plugs
  • Spark plug wire set
  • 1 Can aerosol carburettor spray
  • 3/8-Inch drive ratchet and socket set
  • Spark plug removal socket set
  • Spark plug feeler gauge tool
  • Serpentine V-belt
  • Fuel filter
  • Drain pan or dripping pan

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  1. 1

    Remove the nut that holds the air filter assembly lid to the engine. Remove the air filter assembly lid and replace the air filter.

    How Do I Tune-Up My 1978 Triumph Spitfire?
    (filtre à air image by Philippe BERNARD from
  2. 2

    Start the vehicle and let it idle, making sure the car is in "Park" or "Neutral". Using the throttle linkage on the side of the carburettor, rev the engine a little and hold at a higher RPM. Spray the entire contents of the aerosol carburettor cleaner can into the carburettor. If the vehicle stalls, restart and give the engine more throttle during the spray application. The carburettor is the mechanical device in the centre of your air filter housing.

  3. 3

    Maintain an idle on the car for at least 30 seconds after emptying the carburettor spray can. This will ensure that the car does not get flooded with fuel at the next start up. Shut the car off. Reinstall the air filter assembly lid and tighten the wing nut down to 20ft-lbs. of torque.

  1. 1

    Remove one of the spark plug wires at the plug end. The spark plugs are on the side of the engine block. Follow this wire to the other end, and remove it from the distributor. Measure the length of the wire against the wires in your new set, and attach the matching length back onto the distributor. The distributor cap is a circular piece with all of your spark plug wires protruding from its points.

    How Do I Tune-Up My 1978 Triumph Spitfire?
    (old spark plugs image by Rog999 from
  2. 2

    Locate and remove the spark plug for which you just replaced the wire. Check the distance of the metal arc to the centre pin in your spark plug with a feeler gauge. The measurement should be .25 in thousandths of an inch. Most spark plugs come with a .44 thousandths gap. Bend the metal arc end towards the centre pin on a hard surface to ensure that your gap is only .25 thousandths.

  3. 3

    Snug the spark plug in with your 3/8-drive ratchet and spark plug socket. Turn the spark plug 1/4 turn once it is snug. In automotive society this is called "snug and a quarter". This will ensure that your spark plug has just the right amount of torque needed to work at optimal efficiency.

  4. 4

    Reinstall the spark plug wire onto the new spark plug. Repeat these steps until you have replaced all four spark plugs.

  1. 1

    Loosen the tensioner assembly on the front of your engine, using your 3/8-drive ratchet and the proper socket. Remove the V-belt from the vehicle.

    How Do I Tune-Up My 1978 Triumph Spitfire?
    (timing belt image by Albert Lozano from
  2. 2

    Make a mental note of the routing of the V-belt for installation. Reinstall the V-belt (or a new one).

  3. 3

    Tighten the belt tensioner until you have less than 1/4-inch of play or slack in the drive belt. If the drive belt squeals upon restarting the car, turn the car off and tighten the belt tensioner 1/4 turn until the squeal goes away.

  1. 1

    Remove the gas cap from the vehicle. Locate the fuel filter on the passenger side of the vehicle, underneath the bonnet. Place your dripping pan directly beneath the filter, as you are going to lose some fuel. The filter is built into the fuel line, and is known as an "in-line" filter.

    How Do I Tune-Up My 1978 Triumph Spitfire?
    (gas tank image by Mat Hayward from
  2. 2

    Remove the forward most hose end, being sure that is not aimed in your direction. Removal of fuel lines will cause some loss of system pressure, and fuel dissipation. Remove the second end of the fuel filter, and hold the fuel filter sideways, so that both ports are not dripping. Place the old filter into your dripping pan.

  3. 3

    Reinstall the fuel filter into each end of the open fuel line. Tighten the clamps to ensure that no fuel is emitted after completion of this job.

  4. 4

    Loosen the wing nut at the top of the air filter housing and remove the air assembly lid. Pour about five ounces of fresh gasoline into the carburettor directly. This will prime the carburettor so that it is not bone dry when you go to start the car.

  5. 5

    Reinstall the air filter assembly and tighten the wing nut to 20ft.-lbs of torque. Start the vehicle in neutral or park. Inspect your fittings under the bonnet to make sure that you do not have any fuel leaking from the lines, where you just installed your fuel filter.

Tips and warnings

  • Running a bottle of water dispenser in the spring will help your car dissipate the moisture build up during a sitting period. You can find water dispenser at your local auto parts store and you add it to the vehicle in the same place you add fuel.
  • Gasoline is an extremely flammable liquid. During this entire operation, you will be working around gasoline and the fumes from the gasoline. Keep away from spark, cigarette smoking, and open flame during this project. Failure to adhere to this warning may result in burns, vehicle or personal damage, or even death.

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