How to Adjust Ignition Timing

     A good way to make sure your car is running properly and you are getting good gas mileage is to make sure your ignition timing is adjusted properly.  If you ever hear a pinging noise, which sounds like marbles rattling around in your engine, your ignition timing may be too advanced. If your timing is too advanced then your car will be suffering from power loss and excessive pinging that can shorten the life of your engine. Pinging is the result of your car's spark plugs firing too early, as the piston is rising towards the top of it's compression stroke. This will cause the combustion that is taking place to actually try to force the piston the opposite way that it is traveling. This results is power loss, poor fuel economy and unnecesary stress on the engine.

     If you have noticed that your car seems to suffer from low power at the lower RPM's or seems sluggish, the ignition timing may be considered "retarded". This means that the spark plugs are firing too late as the piston has traveled past the optimum firing point, causing low power, high emissions and possibly unburnt fuel to enter and burn in the exhaust. Retarded ignition timing and overly advanced ignition timing can be diagnosed with a timing light or a test-drive if you are unable to purchase a timing light. Timing lights are pretty inexpensive and you can pick up one from an auto parts store for under 40 dollars usually.

     I'll start with the test drive method since most timing lights will come with instructions and the timing specifications should be located on your vehicle under the hood on an emissions label. If you're suffering from pinging, then you'll want to retard the ignition timing. If you have adjustable ignition timing then there should be a lockdown bolt holding the distributor in place (It will be the round thing with the spark plug wires running out of the top of it). If you're able to find the distributor and it has a lockdown bolt with an adjustment slot, then you have adjustable ignition timing. You'll want to rotate the distributor either clockwise or counterclockwise depending on the engine. One way to tell if you're advancing or retarding when turning the distributor, is if the engine slows down then you are retarding the ignition timing. If it speeds up then you're advancing. You'll want to advance to the point you either hear ping or the engine seems to smooth out noticeably. If you hear ping then you need to turn it back the opposite direction until you hear no ping, then lock down the bolt.

     You'll need to take the car for a short test drive to see if you're still getting a ping under load. This is the most important part. You'll need to floor the accelerator to put the engine under full load, preferably going uphill. If you hear any noises, then you'll need to retard the timing more (turn the distributor in the direction that decreases engine speed ). Either pull over to a safe place if you've brought tools with you, or bring it back to the driveway. You'll want to retard to the point that you don't get any ping under full load. This is optimum ignition timing. You may have to do some fine adjusting back and forth to get your ignition timing just right. This is where a timing light will help to keep track of your changes. A timing light has 3 connections. One connection hooks to a spark plug wire (usually the number one wire). 2 other connections connect to the car battery (one positive and one negative). With the engine running and the timing light hooked up properly, you should be able to pull the trigger on the timing light and get a strobe flash from the light. You aim the light  at the crankshaft pulley on the vehicle and you should see marks located on the pulley. This is where you wiil probably need an service manual or do some research to find out what your particular pulley marks mean. There will usually be a set of marks, each mark corresponding to either 5 or 10 degrees. For example 6 marks on the pulley will indicate 30 degrees if each mark equals 5 degrees. The first mark might indicate 0 degrees or TDC (Top Dead Center) and the last would indicate 30 degrees BTDC (Before Top Dead Center). TDC is the top of piston travel as the crankshaft rotates and the piston travels upward in the cylinder. BTDC is the term used to indicate timing usually. An automobile's  timing specification will usually be in degrees BTDC. Occassionally  the first mark might indicate ATDC (After Top Dead Center).  ATDC indicates the piston has already traveled past TDC and is traveling down the cylinder as the crankshaft rotates. It is important to check any reference material you can find either online, or a service manual to find out what your vehicles pulley marks indicate. You could think of increasing values of degrees as gaining BTDC. Try not to focus on the words "after" and "before" TDC as this can get confusing sometimes.