Shouldn’t cost you anything if all the parts are there.
Optional: Distributor cap, points, condenser, rotor arm, distributor felt pad, engine assembly grease, carb cleaner or degreaser.
Optional parts: Distributor cap, points, condenser, rotor arm, distributor felt pad.
Philips screwdriver, small flat headed screwdriver, feeler gauges, cotton buds, super fine wire wool, vacuum pipe, engine assembly grease, carb cleaner or degreaser.
Additional link on how to custom make HT leads and using the correct spark plugs and setting spark plug gaps can be found here. The document is pretty large article.
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My car had developed a real uneasy idle and I put it down to some bad fuel, water in the fuel, when all this started. It’s a known fact that ethanol will absorb water. The mustang gas caps are not exactly air tight like todays gas caps are. The car has been in storage for most of the year, as pretty much everybody else’s classic cars to fair. So the problem sort of crept up on me.
I decided to do a rebuild of the distributor to make sure it wasn’t the Pertronix gap, vacuum advance or weights causing the issues.
I decided to check the HT leads to make sure they were OK too. When I removed lead 3 There was a problem. The cap had corrosion in it.
I don’t know if the removing of the lead caused the break or was already broken, but this certainly wouldn’t help the cause in any shape or form.
I decided that I needed to do a complete ignition overhaul, new lead, cap and rotor arm. I gave Mustang Maniac a call and went to go pick up my bits. The old lead looks to have been hanging on by the merest slithers of metal at the angled part in the rubber boot, not allowing a full current for the spark.
Lifting up the cap things were not good inside. The cap had cracked at the back and the rotor arm was hitting the top of the cap, more on the causes for that later.
Disclaimer (just in case): If you are in any doubt on your ability to do this – DON’T. Get it wrong you and could damage the insides of the distributor and the car wont start. This is a guide on how I done it, I can’t held be responsible for your actions.
First part is to make a note of where the HT (spark) leads go and to what cylinder. Take a few photo’s if you’re not sure, or label the leads up with a marker or sticky label of some sort. If you look closely the top of the distributor cap has the number ‘1’ on the top, this is where you plug the lead for cylinder one.
If you are unsure here is the firing order of 260/289/302 with a standard cam. If you are unsure; CHECK your current working setup, then check again before removing the leads.
Take the leads of and unclip the front and rear retaining clips to release the cap. The rotor arm can now be removed and the small usually oil soaked felt pad under it can be removed.
Depending on your set up there will either be a set of points and condenser picture below left, the points gap will be covered a bit later once the rebuild is completed.
An upgraded set of electronic points as mine below right will be set to the manufacturers gap, more on that later once the rebuild is completed.
I will be removing the electronic set up, but once the condenser and points are removed the principle is exactly the same for dismantling and re-assembly.
The Pertonix is held in place by a single screw at the bottom of the shoe which also holds in place the earth strap as well. The screw should also have a sprung non slip washer to stop the sensor (and points) from moving once tightened. Lift the Pertronix sensor out of the way. On the underside you will see a small pin which locates the other end of the sensor to stop it moving around. This locates into a hole which I have arrowed below. This hole is also used for the top part of the points to hold them in place and stop movement. I don’t need to remove the Pertronix fully, so I just moved it out of the way for now. You can do the same with the points, or undo the condenser and distributor wires if you intend to replace the points later.
Next remove the magnetic collar from the shaft. You can remove the collar first or at this stage it doesn’t matter.
Disconnect the vacuum pipe to the front of the vacuum canister on the front of the distributor. Check for any leaks or cracks. If you find some replace it.
Next there is a metal lever that goes into the distributor (this will now be known as “dizzy” from now on). There is a tiny clip that holds the bar onto the pin. Remove the clip very carefully and make sure you don’t loose it.
Locate the two screws on the front of the Dizzy that hold the vacuum canister in place. You should now be able to move the canister around and gently lift the arm from the retaining pin. remove the vacuum can.
Check for signs of perishing. To check the function of the vacuum you can suck the can from the front and you should see the arm move towards the inside of the can, repeat a few times. If all is good you can clean it up and keep it safe.
Next remove the screw that holds the earth strap to the lower dizzy plate.
There is a screw located just above the strap on the upper plate, this would have held the condenser in place. You don’t need to remove it, but I did just for the sake of it. It fills a little hole to stop dirt at least.
Next to the cam lobes there is another e-clip at the top of a pin. This holds a washer and under that a fairly strong sprung washer. Slip a small flat ended screw driver and gently tease it away. If you’re not careful it will ping up and be lost in the depth of the engine bay.
With the clip removed remove the top washer.
With washer removed you can now see the sprung tension washer. Make a not of which way up it sits.
That’s the last of the retainers for the top plate. You should now be able to lift the plate up and lift it up over the lobes of the cam.
The lower plate is now held in place with a single screw the opposite side to where the cables come into the dizzy. Undo the screw and remove the lower plate.
Removing the lower plate there should be three raised points which separates the upper plate and should be smooth. I noticed one of mine was loose so I removed it. You can see the hole next to the pin in front of my thumb. I will stick this back on later.
With the lower plate removed you can now see the advancing weights and springs.
These springs are different tensions. The top one has less tension and and allows the weights to swing out under rotation advancing the timing. The lower spring is stiffer and at certain centrifugal force this spring takes over slowing down the advance. The larger and stronger spring is a loose fit to the anchor points.
On top of each weight there is again a an e-clip. Remove with a small flat ended screw driver and make sure it does not ping off. Make a note of which weight goes where.
Remove the clip and lift up the weight. Repeat for both sides.
Keep the separate or mark up a piece of paper and lay them on the paper so you know which pair go together and if they are the 13deg weight side or the 18deg weight side.
without taking the whole dizzy out this is about as far as you need to go.
You could possibly remove the springs, the two springs making careful notes on what one goes where. I decided against that just in case i stretched a spring putting it back on. This would have an effect on the timing and advance. My springs weren’t to bad so I decided not to chance it.
Now you need to clean the inside and remove any old dried grease and debris. Don’t go made in here with the fluids, use just enough to clean. I found carb cleaner is good, and also sprayed onto a cotton bud to clean the springs and surrounding area.
You can move the move the weight plate with your fingers to clean parts that are partially covered. Don’t go mad with forcing open of the springs, you don’t want to stretch them. Make sure there is no bits of debris in the bowl or trapped anywhere.
The bowl should now be clean.
I started with the weights. take each weight and either clean with a degreaser or similar, or take some ‘000’ grade super fine wire wool to take the roughness of the weights.
Make sure NO wire strands are left on the weights or fall into the dizzy bowl.
I used a small punch to wrap a little wire wool around and then clean the inside of the holes. You are lightly cleaning – not reboring the hole. Also clean the clip, any rough edges could impede the movement of the weights.
With the weights and clips cleaned it was time to fit them back to the dizzy. You will need some lubrication. I researched and the general recommendation is an engine assembly grease.
To use this grease you only need a light smear and not a huge blob. Apply some grease to the weight posts and the edges where the weights rest and move against with a cotton bud.
If you examine the weights it easy to see where the wear marks are, apply a little grease to the weight. wear points and into the holes. Note that the whole weight doesn’t need greasing, just the outside edges, the top where the clip holds it in place and the underside where it rests on the pin base.
Place the weight over the pin and move it into position. There may be some excess grease but that can be removed. Make sure the weight is free to move and rests within the cradle.
Apply a film of grease to the clip and place onto the weight.
You need to press the clip onto the post into the recess. I found again a small flat headed screw driver would do the trick. IT can take a few goes to get right. Just make sure it doesn’t ping away. I have also seen these refitted with with a pair of needle nosed pliers to get an even pressure onto the post.
The picture here shows both clips in place holding the weights. Make sure the weights move freely and that the clips are securely in place.
Lower plate needed some love in respect that the plastic/nylon stop had worked a bit loose. I forgot to take a picture of it as I was more interested in the repair which I wasn’t expecting.
Both the front and the back of the lower plate was cleaned with fine wire wool. You can see the slide pads are just hot pressed into the holes of the plate. I degreased the missing area fully and then stuck the pad in place with some super strong glue. With the plate now repaired I cleaned the yellowish and two red pads of old grease and debris. I took some 5000grit and then 8000grit to remove any rough parts. Not sand it down, but more of a polish.
Pay attention to the post this needs to be clean and without any burrs.
Again make sure NO wire wool is on the plate before refitting. Place the plate back into the bowl area to cover the plate with the post side facing upwards. Align the hole and screw into place.
Take your assembly grease on a cotton bud and apply a film over the plastic pad areas and the post.
The upper plate may need a clean with wire wool or degreaser depending on the state of it. Pay attention to the brass bush which sits on the post of the lower plate. Brass is a soft metal and you don’t want to create a problem, with the small punch and a degreaser with fine wool clean out the bush fully. Remove any burrs on the top side of the bush to allow the sprung washer to move without snagging.
On the underside of the upper plate you can see where the plate has moved across the slide pads. Apply a film of the grease on these areas and into the brass bush.
Apply some grease to the small upper post for the vacuum can.
Place the upper plate onto the lower plate, locating it via the brass bushing. make sure it’s free to move all the way. Clean the components that hold the top plate to the bottom plate. Top washer, sprung washer and the e-clip. These need to be clean and smooth in order to not snag the movement.
To refit a further film of grease over both sides of the of the sprung washer on top of the top plate brass bush with the curled edges facing up. Top washer with grease applied on the top and bottom, place the washer on top of the sprung washer.
The e-clip needs grease on the underside, so rest it on top of the washer. The washers need to be pressed down slightly in order to expose the retaining ridge on the post. At the same time as holding the washer down, press the e-clip onto the post. Slightly awkward to do, but again make sure this doesn’t ping off.
That’s the worst of the rebuild completed. Next we need to refit the cleaned up earth strap for the top and bottom plates. If you have an old school condenser now is the time to attach it onto the top plate. Placing the wire ready for the points around the cam.
On the Pertronix setup, wipe over the plastic collar and slip it over the cam lobes with the recess facing upwards.
With the vacuum advance module clean the arm at the back and apply a film of grease on both sides near the hole and in the locating hole.
The vacuum module can only fit on in one way following the curve on the outside of the dizzy. Thread the arm through the opening and locate onto the top plate pin.
With the arm located take the e-clip clip with some grease and again fit into place so that the arm is held down.
With the arm secured now refit the two screws to hold the vacuum in place. Make sure everything is able to move freely.
a) Pertronix or electronic ignition setup.
NO grease at these points as you don’t want the sensor to move, once setup.
Now place the Pertronix on the plate, and the other end of the earth strap that is attached to the bottom plate on top of the Pertronix while aligning the top pin to the other locating hole. (This pin into the hole would be where the top screw for the points would have gone.)
With the sensor and the collar in place you need to set the correct gap. There is no cam lobe to set. A ‘tool’ is supplied with Pertronix which is a plastic strip to set the gap. Left pic shows the gap is to small. The right pic shows the correct way to gap the sensor. Keep the plastic gap tool flat to the sensor face and slide the the unit until there is a slight drag between the collar and the sensor. Tighten the bottom screw fully.
Correct gap setting at 0.80mm.
- I have been asked why there is only one screw and a pin for the Pertronix and two screws for the points. Simple answer is that the points are under a sprung load toching the dizzy cam. The Pertronix does touch anything and senses the magnets spinning past it.
- What is the gap for the pertronix? It’s 0.80mm and 0.0315 of an inch
b) Points setup.
NO grease at these points as you don’t want the points to move once setup.
If you have the points set up, place the screw on the lower part of the points, and then locate the holes at the top of the points and add the other screw to hold in place on the plate. Tighten to a slight nip so it doesn’t freely move, but can be moved by hand with a slight effort. Attach the dizzy cable to the points and the remaining end to the points and tighten the connections up. (Not a great picture I found on the net, but it gives an idea.)
To set the points you need to turn the engine over by hand from the crank, or a manual car put in gear and rock the car till the cam moves around. Align the highest part of one of the cam lobes is directly under the nylon/plastic points foot. Using a feeler gauge set the gap between the point contacts to the recommended settings in your owners manual. Usually 0.017 or 0.021 thou. Once the gap has been set correctly hold in place making sure the spring tension doesn’t move the gap. Tighten the two screws fully. Apply a thin film of grease around the cam lobes. Points Set.
Tip: I usually would start the car, and run for a minute or so with a little revving. Then re-check the point’s gap to make sure it hasn’t moved and is still the correct setting once things have settled down.
In the centre of the dizzy where the rotor arm sits is a recess. This has a felt pad to oil which is to keep the cam lubricated lower down. I would recommend this is replaced with a new one and filled with fresh oil, or reuse the old one with the old oil it’s up to you. Most people use a drip of the engine’s dipstick at oil change. But my research leads to me to say that this should be a very light engine oil to allow the oil to run through the felt. It’s debated if this is still required. But Ford wouldn’t have milled out the centre shaft and put a felt pad in there for no reason!
Place the rotor arm on top of the dizzy shaft and locate into place. These can only fit in orientation as there is a keyway on the inside of the rotor to match with the shaft cut out.
It has been noted that on some rotor arms they don’t fully fit onto the shaft with Pertronix collar in place. This is easily cured by rubbing the bottom of the rotor arm on some glass paper and remove a millimetre or two. Try to keep the sanding flat and even as possible, although it shouldn’t make to much difference. But these rotor arms and spinning around in there at some silly speeds. Keeping the rotor arm balanced is good practice. I used my callipers to make sure it was even all the way around removing any high spots. Replace the rotor and it should snap into place.
Refit the dizzy cap and clip into place.
Now take your marked up HT leads or follow the chart and fit back onto the dizzy cap.
Job done – start the car and off you go.
Making a HT (spark plug) lead click here.
Spark Plug replacement and maintenance click here.
Three hours or so. But it took me longer with taking pictures for this guide.