There is a very large class of people that own 65/66 Mustangs that, as far as I can tell, anyway, have been, for the most part, ignored entirely. They don't really want that 100 pt. show car that is so nice and was soooo expensive that they're afraid to drive it, they also don't want to make their car capable of achieving warp factor three. They just want this car that they dearly love to be able to cruise around smoothly and reliably, without having it dump them out on the side of the road or have it start making weird noises or belching out big clouds of funky-smelling smoke. And I think, truth be told, that this is by far the largest class of Mustang owners. They take their car to some technician when what they actually need is a mechanic, and this, frequently, does not work out very well at all for the owner. They don't want to re-engineer the entire car, they just want someone to fix what broke. These are the people that I am trying help out with this blog. Some problems require a little bit of back and forth, as in, "Try this." "I tried that and it didn't change anything."
" Oh. well, you probably need to try that." " I tried that and it helped, but it still isn't quite right." "Now you need to try this...." If you go to http://www.allfordmustangs.com/ and then go to the classics forums, you will be able to do that with a pretty hefty gathering of some very knowledgeable people that also happen to be very friendly. None of that ridiculous one-upmanship, no flaming or abuse, none of that stuff. Just good, solid advice from people that know what they are talking about.

Sunday, March 30, 2008

Setting the points in your distributor

Contrary to popular opinion, setting the points in your distributor is not a dark art. It is actually a very simple procedure. In the picture on the bottom, the point gap, circled in red, is closed and there is a yellow arrow pointing at one of the 8 ( or 6 on 6 cyl car) distributor cam lobes. In the picture on the top, the points are open and the point gap is indicated by the yellow arrow. After removing the distributor cap and rotor, and then installing the new points, rotate the crank shaft in a clockwise direction from facing the motor with a 15/16 socket wrench on the big bolt in the middle of the crank shaft pulley until one of the bumps on the distributor cam is holding the points all the way open. If the points don't seem to open at all when you rotate the crank, loosen the screws and move the points in closer to the middle of the distributor, so that, as the distributor turns, the points open and close.. With the two mounting screws loose enough to slide the points back and forth, move the points to the place where the gap is correct. On a 6 cyl car the point gap should be .024-.026 inches, on a 260 or a non-hipo 289 the point gap should be .014-.016 inches and on a hipo 289, or K code, the point gap should be .019-.021 inches. Then tighten up the two mounting screws. A hipo 289, the K code, is supposed to have a dual point distributor. On these, you do what you just did twice, as there are two sets of points in there instead of just one. The reason that the hipos got this type of distributor was because the motor was designed to run at much, much higher RPMs than the other motors, and in extremely high RPM situations, something called 'point float' can occur. That's when the points don't really close quite right and sort of hang around the outside area of their travel and flutter. Having two sets of points greatly reduces the frequency and severity of this happening.
Breaker point ignition systems have fallen into ill-favor in most circles, but personally, I don't think that they deserve this. A whole bunch of cars kept chugging down the road for a whole bunch of years running on breaker points. I have a pertronix unit in the distributor of my car, because they function consistantly until the day that they fail entirely, kind of like a light bulb, but I also keep a set of points and condensor in the glove box of my car, because that is something that I know for sure will work, and is a very simple swap, in case I have to do that on the side of the road.

Just a quick update. I now have the points back in the distributor instead of the pertronix. I got tired of having something in my car that I didn't understand and, consequently, didn't trust.


Don said...

Good info on the HiPo distributor.
I'd like to clarify a point (pun intended); the primary purpose of dual points is to increase the "dewll time" during which the coil's magnetic field is developed. Increased dewll time results in better coil saturation and a hotter spark.
The two points are offset by a few degrees so that you get- in effect- a longer "colsed points" time. Thus when you set up point gaps on 2 points you need to adjust the crank so one set of points is on the peak and adjust the gap.
THEN you need to slightoy rotate the crank again to get the other points on the cam lobe peak.
If you don't do this you will misadjust the points.
Don Antilla
Southbury, CT

Veronica said...

In one sense that is correct. On the hipo distributor, the spark plug starts firing when the first set opens, and quits firing when the second set closes, so, yes, you do get a better spark, also.

On that 'setting one then the other' thing, that was what I meant by do it twice, but, your explaination is much clearer and easier to understand, and that's what we are all striving for. I want everybody's car to run as smoothly and reliably as possible.

Unknown said...

The coil fires only after the second (lagging) point gap opens up. This is what causes the magnetic field in the coil to collapse after having had a full saturation due to the angular overlap of the two sets of points. The purpose of the dual points is to provide a longer "points closed" time so the magnetic field can build up as close to saturation as possible. Then when the second point pair opens, you get a stronger high voltage to the plugs than with a single pair of points.