4 replies to this topic

[Tripyrenees]

Hello -

After reading the Hanyes manuel, i still can't figure out exactly how the timing work ... Could any one give me a detailed step by step in how to time my engine please !

( I'm tried earlier today, failed terribly, ) Oh and i don't understand why the vacuum on my distributer hits the metal oil pipe and the other bolt the other side with the white cable coming out ... is this normal ?

Thank you

[lrostoke]

Have you got a timing light ??

[Tripyrenees]

Yes i do

[dklawson]

Let's start with a basic discussion of what the timing "is" and what the timing light is showing you. I will focus on points ignitions.

Ignition timing is basically synchronizing the spark to occur at a specific degrees of crank rotation. The crank drives the camshaft by chain, the cam drives an intermediate gear perpendicular to the cam... which in turn rotates the shaft and cam inside the distributor. The camshaft and the distributor shaft turn at 1/2 the crankshaft speed. Inside the distributor is a four lobed cam that opens the ignition points 4 times per dizzy revolution (twice per crankshaft rotation). Since everything is hard connected by chain or meshed gears, the distributor housing is rotated in the block to insure that the 4-lobed cam inside it opens and closes the ignition points at the correct angular crank position.

Now let's discuss static timing. That is a rough adjustment made without the engine running. The abridged explanation is that you bring piston #1 NEAR TDC on its firing stroke. (Firing stroke will be indicated by both rocker arms for cylinder #1 being "loose" and free to move by hand with the valve cover removed). Turn the crank in the normal direction of rotation, stopping at the desired number of degrees BTDC. Connect a test lamp between coil (-) and earth. Switch on the ignition and loosen the dizzy clamp. Turn the dizzy housing COUNTERCLOCKWISE until the test lamp is "OFF". Now SLOWLY turn the dizzy housing CLOCKWISE until the test lamp just lights. The lamp will light when the points "open". It is at that exact moment that the spark will be produced. You have just set the timing such that you will get a spark each time the crank reaches the number of degrees BTDC that you chose. FWIW, a setting between 5 and 8 degrees BTDC will typically be good enough to start an engine.

Static timing was the norm on engines prior to emissions concerns. Setting the timing with a light became more important when emissions controls were added to cars. Setting timing with a light is "dynamic timing" because it is carried out with the engine running. You must have the timing set close to correct just so you can start the engine. (When in doubt, first set the static timing as discussed above). Once you can start the engine, bring it to normal operating temperature. Connect your timing light to the spark plug wire for piston #1. Disconnect the vacuum advance line at the distributor and plug the open line going to the carb. Adjust the idle speed as listed for your engine. Now loosen the dizzy clamp bolt SLIGHTLY. Point the timing light at the marks on the front pulley. With a basic timing light you should see various marks line up with the pointer. Check your manual to determine which is right for your engine. While pointing the timing light at the pulley, turn the dizzy housing SLOWLY until the desired timing mark lines up with the pointer. Lock the distributor down reconnect the vacuum advance, reset the idle speed if necessary, and you are done. You have set the dynamic timing per the factory specifications.

Lastly there is maximum advance timing. Few of our engines are as they were when they left the factory. Therefore, the factory timing specs may not be applicable any more. In this case, start and warm the engine as above. Plug the vacuum advance line as above. Now bring the engine speed up to 4000 RPM using the idle adjustment screw(s). Use your timing light as above but set the timing to 32 BTDC and lock the dizzy down. Reset the idle speed and take the car for a test drive. During your drive, place the engine under a heavy load (accelerate uphill in too high a gear) while listening for knocking and pinging. If you hear any, return home and retard the timing in 2 degree steps until you no longer hear pinging on your test drives. You have now set the timing as far forward as possible for your engine's condition, state of build, and the fuel you use. As a footnote to this last procedure, it is much easier to set the max advance timing if you have an advance timing light (the ones with the knobs on the back). Alternatively, you can use a traditional timing light but you will need to add a 32 BTDC mark to the pulley.

[Tripyrenees]

Let's start with a basic discussion of what the timing "is" and what the timing light is showing you. I will focus on points ignitions.

Ignition timing is basically synchronizing the spark to occur at a specific degrees of crank rotation. The crank drives the camshaft by chain, the cam drives an intermediate gear perpendicular to the cam... which in turn rotates the shaft and cam inside the distributor. The camshaft and the distributor shaft turn at 1/2 the crankshaft speed. Inside the distributor is a four lobed cam that opens the ignition points 4 times per dizzy revolution (twice per crankshaft rotation). Since everything is hard connected by chain or meshed gears, the distributor housing is rotated in the block to insure that the 4-lobed cam inside it opens and closes the ignition points at the correct angular crank position.

Now let's discuss static timing. That is a rough adjustment made without the engine running. The abridged explanation is that you bring piston #1 NEAR TDC on its firing stroke. (Firing stroke will be indicated by both rocker arms for cylinder #1 being "loose" and free to move by hand with the valve cover removed). Turn the crank in the normal direction of rotation, stopping at the desired number of degrees BTDC. Connect a test lamp between coil (-) and earth. Switch on the ignition and loosen the dizzy clamp. Turn the dizzy housing COUNTERCLOCKWISE until the test lamp is "OFF". Now SLOWLY turn the dizzy housing CLOCKWISE until the test lamp just lights. The lamp will light when the points "open". It is at that exact moment that the spark will be produced. You have just set the timing such that you will get a spark each time the crank reaches the number of degrees BTDC that you chose. FWIW, a setting between 5 and 8 degrees BTDC will typically be good enough to start an engine.

Static timing was the norm on engines prior to emissions concerns. Setting the timing with a light became more important when emissions controls were added to cars. Setting timing with a light is "dynamic timing" because it is carried out with the engine running. You must have the timing set close to correct just so you can start the engine. (When in doubt, first set the static timing as discussed above). Once you can start the engine, bring it to normal operating temperature. Connect your timing light to the spark plug wire for piston #1. Disconnect the vacuum advance line at the distributor and plug the open line going to the carb. Adjust the idle speed as listed for your engine. Now loosen the dizzy clamp bolt SLIGHTLY. Point the timing light at the marks on the front pulley. With a basic timing light you should see various marks line up with the pointer. Check your manual to determine which is right for your engine. While pointing the timing light at the pulley, turn the dizzy housing SLOWLY until the desired timing mark lines up with the pointer. Lock the distributor down reconnect the vacuum advance, reset the idle speed if necessary, and you are done. You have set the dynamic timing per the factory specifications.

Lastly there is maximum advance timing. Few of our engines are as they were when they left the factory. Therefore, the factory timing specs may not be applicable any more. In this case, start and warm the engine as above. Plug the vacuum advance line as above. Now bring the engine speed up to 4000 RPM using the idle adjustment screw(s). Use your timing light as above but set the timing to 32 BTDC and lock the dizzy down. Reset the idle speed and take the car for a test drive. During your drive, place the engine under a heavy load (accelerate uphill in too high a gear) while listening for knocking and pinging. If you hear any, return home and retard the timing in 2 degree steps until you no longer hear pinging on your test drives. You have now set the timing as far forward as possible for your engine's condition, state of build, and the fuel you use. As a footnote to this last procedure, it is much easier to set the max advance timing if you have an advance timing light (the ones with the knobs on the back). Alternatively, you can use a traditional timing light but you will need to add a 32 BTDC mark to the pulley.

thank you !! i shall get that done today