I know how to find tdc on car but i am not sure on how to put distributor back. I turned engine over and forgot to mark rotor, what should it be pointing at on the cap. Thank you, Joe

HI, if you put the engine marks on the front pulley to TDC, when you put the distributor back in make sure that the rotor arm is facing toward the number one plug lead- good luck.

pull the distributor
turn the crank to tdc compression stroke ( remove n1 plug and put you finger over the hole to get compression stroke ) line the rotor button up with no 1 plug lead
move the rotor button back about 1/2 inch and insert the distributor
as you push it in the button will move around to line up
keep adjusting the button back until it lines up
tighten the distributor down

You might not have #1 at tdc on the COMPRESSION stroke. You're trying to get it to tdc the hard way. Take #1 plug out and have someone bump the starter while you hold your thumb over the plug hole. You'll know when its a tdc cause it'll blow your thumb off. When youve got it close, turn the crank to absolute tdc using the timing marks on the harmonic balancer. Take the distributor out and pull the cap off. Then turn the distributor rotor to point at the #1 plug on the distributor cap. Put the distributor back in and put the cap back on. Make sure that the oil pump slot lines up right, as the distributor won't sit flush until its right. If its not lined up, take a long flathead screwdriver and turn the oil pump to make the two line up. Last, make sure the wires are on the right plugs on the cap using the firing order cast into the intake manifold. Remember that the rotor turns COUNTER clockwise.

When replacing the distributor you have to make sure it is kept "in time".
If you did not keep it in time, then you will have to retime the distributor.

How to time an Engine

Technique used before and during the reinstallation of the distributor.

Note: Requires two people or a special momentary contact bump switch.

1. Find the TDC mark on the harmonic balancer. Clean it off if necessary so you can see it easily.
2. Remove the #1 spark plug and place your thumb over the spark plug hole.
3. Have your helper bump the engine over carefully using the ignition switch or you can do it using a specially made bump switch connected to the starter solenoid.
4. When you feel and hear pressure build up and escape from under your thumb stop bumping the engine over.
5. Look at your harmonic balancer. If the TDC mark is not lined up with the timing pointer, then you will need to rotate the engine in its normal running direction with a socket and ratchet or breaker bar placed on the harmonic balancer bolt. Turn the engine carefully, exactly lining up the TDC mark with the timing pointer. If you go past the TDC mark you will have to start over.
6. Once the TDC mark is lined up properly with the timing pointer you are ready to install the distributor. Make sure your oil pump driveshaft is in place then place the distributor in the hole. Do not force it. Carefully rotate the distributor shaft until the distributor falls into place. Then put the rotor on the distributor and make sure it is pointing at #1 plug wire terminal on the distributor cap. It may take several tries to get the distributor rotor pointing in the correct direction.
7. Once you have the rotor pointing at #1 plug wire terminal on the distributor cap, snug the distributor clamp down and you are ready to install the cap and run the plug wires. Then you can start the engine and set the timing to the specification desired using a timing light.

The ignition timing is not adjusted with a timing light or with the engine running, and to set the ignition timing follow these procedures.

There is a mark or notch on the distributor housing that the rotor should be pointing to when the engine is on TDC. (Top Dead Center) This "Static" timing is all that matters and the computer will be able to control the timing as long as the ignition rotor is in that position when the engine is at TDC.

1. Place the engine at top dead center.

2. Look under the distributor cap and find where the number one terminal runs under the distributor cap, and where that position on the distributor cap corresponds with the distributor housing, and it should match up to a mark or a notch on the distributor housing (usually has a #6 for 6 cylinder engines or a #8 for 8 cylinder engines) indicating the number one TDC alignment position.

3. With the engine on top dead center the ignition rotor should be pointing to the number one TDC alignment mark or notch that is on the distributor housing, if it is not then loosen up the distributor and turn the distributor until the ignition rotor is pointing to and aligned with the TDC alignment mark or notch on the distributor housing and then tighten down the distributor, the engine should now be "Static" timed. (The more precise that you are aligning the TDC alignment mark with the ignition rotor the better the engine will run, and it will be less likely that there will be a camshaft to crankshaft correlation problem)

If the distributor can not be turned enough to align the ignition rotor with the number one TDC alignment mark on the distributor housing, or the distributor does not set properly and will not allow the installation of the spark plug wires then the distributor is not installed correctly and is most likely a tooth off and it will need to be re-installed correctly. (The distributor should set like it is shown in the firing order diagram when it is properly installed)

Here is a firing order diagram to also help assist you.

Some distributors have the hold down bracket secured onto the distributor housing and the distributor can not be turned into alignment and then tightened down into that position, and these distributors will only fit into the engine and correctly align on "Static" timing one certain way, and when it is correct the distributor hold down bracket bolt can be installed and the TDC alignment mark on the distributor housing will remain properly aligned with the ignition rotor.

The ignition timing is not adjusted with a timing light or with the engine running, and to set the ignition timing follow these procedures.

There is a mark or notch on the distributor housing that the rotor should be pointing to when the engine is on TDC. (Top Dead Center) This "Static" timing is all that matters and the computer will be able to control the timing as long as the ignition rotor is in that position when the engine is at TDC.

1. Place the engine at top dead center.

2. Look under the distributor cap and find where the number one terminal runs under the distributor cap, and where that position on the distributor cap corresponds with the distributor housing, and it should match up to a mark or a notch on the distributor housing (usually has a #6 for 6 cylinder engines or a #8 for 8 cylinder engines) indicating the number one TDC alignment position.

3. With the engine on top dead center the ignition rotor should be pointing to the number one TDC alignment mark or notch that is on the distributor housing, if it is not then loosen up the distributor and turn the distributor until the ignition rotor is pointing to and aligned with the TDC alignment mark or notch on the distributor housing and then tighten down the distributor, the engine should now be "Static" timed. (The more precise that you are aligning the TDC alignment mark with the ignition rotor the better the engine will run, and it will be less likely that there will be a camshaft to crankshaft correlation problem)

If the distributor can not be turned enough to align the ignition rotor with the number one TDC alignment mark on the distributor housing, or the distributor does not set properly and will not allow the installation of the spark plug wires then the distributor is not installed correctly and is most likely a tooth off and it will need to be re-installed correctly. (The distributor should set like it is shown in the firing order diagram when it is properly installed)

Here is a firing order diagram to also help assist you.

You need to mark in 2 places. With the cap off mark the position of the rotor button on the distributor housing first. Then you need to make a mark on the distributor housing that will line up with a mark on the engine itself.
When you put the distributor back in back the rotor button up before you put it in because the cam gear will turn it ahead as it seats. For example, if the rotor button is at 3 o'clock then back it up to 1 o;clock.
Don't force the distributor down at the end because you can damage the end that drives the oil pump. Fidle and wiggle it as you push and it should line up and drop onto the oil pump. Also DON'T turn the engine over while it's out or you will have to retime the engine. Hope this helps.

To set the timing on tghe truck, first remove the negative battery wire from battery. Put the truck in netural and set the parking brake,block the rear tires. Remove the distributor cap and check the location of rotor..Then get a socket and ratchet and turn the crankshaft (clockwise) until the timing mark on the crankshaft vibration damper aligns with the (TDC) top dead center mark.Then look at the distributor rotor, it should be pointing at the #1 cylinder on engine. If not remove hold down clamp from distributor and lift up just enough to turn rotor and push back down to check position of rotor. Remember TDC on crankshaft and rotor facing #1 cylinder. Hope this will help.

Get the number one piston up, Take the spark plug out the first one on the drivers side.Rotate the engine until the piston reaches TDC before it starts to decend back. U can use a screw driver to put in the spark plug hole.The rotor must point towards the number one spark plug. your local library will have this infor or autozone

You'll want #1 cylinder at TDC on compression stroke. then line up timing marks at "0" degress /TDC. Firing order is 1,2,3,4,5,6. Drop distributor in, turn rotor ,so rotor ends up pointing at tab on cap for #1 spark plug wire. Distributor turns clockwise. Hope that helps.