The objective of this procedure is to show you how to install the distributor. The distributor must engage with the oil pump drive shaft.
Part 1. Preparation and safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:
- Work clothing - such as coveralls and steel-capped footwear
- Eye protection - such as safety glasses and face masks
- Ear protection - such as earmuffs and earplugs
- Hand protection - such as rubber gloves and barrier cream
- Respiratory equipment - such as face masks and valved respirators
If you are not certain what is appropriate or required, ask your supervisor.
- Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.
Points to note
- Ensure the distributor shaft engages with the oil pump drive.
- Set the engine initial timing before installing the spark plugs.
- Ensure the correct timing order is used to connect the spark plugs.
Part 2: Step-by-step instruction
- Install the distributor
Lower the distributor into the distributor hole. Look at the distributor and you'll see that the rotor is connected to the distributor shaft. The distributor gear is also connected to that shaft. The gear in the distributor and the gear in the camshaft are both helical gears. When the distributor slides in place and the teeth of the distributor gear mesh with the camshaft gear, the rotor will move slightly as the helical gear teeth interlock.
- Engage distributor with oil pump
The slot in the distributor gear has to engage the slot in the oil pump drive shaft which is already fitted onto the oil pump. Often this won't happen on the first try which will mean the distributor may not seat all the way down flush with the block. This is because the oil pump drive rod may not be in the right position to perfectly line up with the bottom of the distributor gear.
During pre-assembly, it was possible to rotate the oil pump drive rod by hand and the distributor dropped all the way down. Now, with the oil pan installed the oil pump drive shaft has to be rotated by hand from the top.
The ideal tool to use is the oil pump primer rod. Put it into the distributor hole and rotate the oil pump drive rod a very small amount. Then give the distributor another try. If it won't drop down yet, rotate it with the drive rod a little more and then try the distributor again. Make sure you hold the body of the distributor in the same position each time.
Eventually the distributor gear will engage the cam gear. It will rotate slightly as it interlocks with the cam gear and slip right in place once it lines up with the oil pump drive shaft. Now the distributor should be fully seated flush with the block or intake manifold.
When installing the distributor, the goal is to get the distributor into place and have the rotor that's bolted to the shaft pointing in the general direction of the number one piston. This is not a firm rule, more of a general guide line. If the rotor tip is pointing in some other direction, the distributor is still installed correctly, but you will need to make a mental note of where the distributor is pointing.
- Set engine initial timing
Before you install the spark plug wires, the engine must be set to the initial timing setting recommended by the manufacturer. This setting should be listed in the repair manual, but in some cars it can be found under the hood on a sticker or label on the air cleaner or radiator. If you don't know what your initial timing setting should be, a starting point of 10 degrees before Top Dead Center will be good enough for the break-in procedure for your engine.
Use this simple method to set the engine to an approximate initial setting of 10 degrees.
If you have a Top Dead Center whistle, screw it in to the number one spark plug hole. Alternatively, plug the number one spark plug hole with your thumb and rotate the engine by hand. If the timing mark passes by and you don't feel or hear air coming out, that means you just passed the exhaust stroke, and you need to keep rotating.
When you feel air rushing past your thumb or hear it through the whistle, take a look at the timing mark on the balancer. Move the crank very slowly and when the timing marks on the balancer and timing cover line up and read 10 degrees - or whatever your initial timing is supposed to be - stop turning.
Now the engine is paused at the exact moment when it will fire a spark from the distributor to the number one spark plug.
Remember, the Top Dead Center mark on the crank will go around twice for one rotation of the camshaft. If you didn't feel or hear the air rushing out of the spark plug hole before the mark lined up, you might have your mark set for the initial timing of the exhaust stoke. Make sure you felt the rush of air, then set the crank at the initial timing setting.
- Line up distributor rotor
The distributor cap will only fit on the distributor one way and when it's on, the body of the distributor can still move left or right to make the spark happen sooner or later as the engine is running. As the engine is at the point of ignition for the number one plug, one of the cap towers must line up with the rotor tip.
With the cap off, hold something as a pointer against the engine and point it directly at the rotor tip. Lower the cap in place and then line up one of the spark towers of the cap with the pointer by rotating it left or right. Which ever tower has the rotor lined up with it now needs a label. This tower is will hold the number one plug wire and will be the starting point of the firing order sequence. Don't let the distributor move from here on. Tighten the hold down clamp so that the distributor body is locked in place and then tighten down the cap.
- Install spark plugs
Install the spark plugs. Check the engine specifications for the plug gap rating and heat range. The gap is directly related to the ignition type, fuel octane and compression ratio. There are a lot of different plug gaps so make sure that you find the right one for your engine. Don't forget to use a small amount of anti-seize lubricant on the threads and torque them to whatever the engine specs say.
The crank is now positioned and the distributor rotor is parked at the moment of ignition for the number one cylinder.
- Wire spark plugs
Every firing order for every engine type starts with a number one, and then the rest of the numbers in the sequence will follow the valve opening events built into the cams of the camshaft. The engine must match this sequence, or it's will not run.
There may be a diagram in your repair manual, but to correctly wire any distributor, all you need is three pieces of information. You need to know the cylinder numbering, the direction the distributor rotates and the engine's firing order.
We already have the rotor inside the distributor set. The firing order, as you read it from left to right, needs to happen in the same direction of rotation that your distributor turns. For example, on a lot of engines, including this one, the firing order starts with 1-8-4-3... and the distributor rotates clockwise. On some other engines, the firing order could start with 1-3-7-2... and the distributor might rotate counterclockwise. The specifications in the repair manual tell you which way to wire up your distributor.
Distributor tower one is at the moment of spark for the number one cylinder, so connect the wire from the tower with the mark on it, to the number one spark plug. Every time the rotor hits that point the spark will go to the number one cylinder.
This distributor rotates clockwise and the next number in the firing order is eight. So, connect the next tower in a clockwise direction to the number eight spark plug. Continue on following the specific firing order. Try to judge the lengths of the wires as you go so that you don't have too much or not enough slack when you get to the last couple of connections.
This type of distributor has an ignition coil built right into the cap. Some engines have separate ignition coils and their caps will have a short wire that comes out of the center of the cap and into the coil that'll be mounted somewhere near by.
When all the plug wires are connected, double check the order of the wires. Plug wiring mistakes are one of the most common causes of start-up problems for new rebuilds, and it's really easy to connect them wrong. When you've double-checked, check again. Repeat the firing order to yourself, and then follow each wire to it's plug as you say the order. Then organize the wires a little with some kind of separators or wire looms.