I posted this story on another thread earlier, but I wanted to ask the broader question - why do points fail and how does one prevent that failure?

I have a 2.0 6 cylinder with MSD ignition, MSD Blaster2 coil and stock points. She has been running great since my engine rebuild, but over the weekend I had a problem. Driving along ripping corners in the country on a nice pre-fall day, and all of a sudden she starts running rough. So, I pointed it toward home and put the pedal down. About a mile out, she gave up and died.

After I got my Father to flat tow me home, I started on the MSD diagnostic procedure. I check everything including replacing the coil, and nothing works. I get to the point where MSD recommends pulling the system out and sending it to them for further analysis....that's when I decided to check the points. A couple of passes with the emory cloth, and she cranked right up.

The points are about 5 years old. They have 3 track events, two autocrosses and about 1000 road miles on them, both pre and post rebuild with about 3 years of sitting idle.

So, does my current system contribute to a shorter life span? Hard driving? Sitting for any period of time? Condensor bad?

I just don't want to get in the habit of replacing points every year just because. Any preventive maintenance I can do will be good.

Dion

Points fail because they run on such low voltage. You probably got some little piece of something in there and that was enough. Hard running is no problem for the points as long as they're adjusted right to where they don't arch. Where I would be most worried about them is when they sit as yours did for three years. They tend to crud up that way.
Any electrical unit like that will wear some, and considering the age of yours, you may consider replacing them as well as the condensor. Still, I think that every year is overkill, especially if the thing stays on the road. My three cents.
Mark D>

Points fail due to friction and heat along with leaving the key on!. Friction, coming from the dizzy shaft rubbing against the fiber block that's on the points arm. Yes, there is grease on there but if you don't change them in 5 years the grease will probably disipate leaving a bare block against metal that's revolving quite fast. Wear makes the block shorter thus changing dwell and (I think) changing timing (correct me if I'm wrong please). As the block gets shorter the points close or get closer to the point of having no gap and eventually shorting out.

Put in a set of Pertronics electronic ignition. They work great. I think there is another form of elec. ignition out there too but at a more expensive rate.

good luck.......

......b

Most of the issue is the the contact material wearing. Every time the points open and close, there is a little bit of a spark. Multiply time running x rpms and you get the idea of what's happening. About a zillion little lightning stikes. Yes, the condensor controls most of this, but it still occurs. MSD helps too. As the gap changes, so does the dwell and timing. Dwell is not a big deal with the MSD.

Best bet is to change out the points for an electronic replacement in form of Pertronix, Crane, what ever else... A search will show many opinions on what's best. I've had good luck with Pertronixs in lots of vehicles until this year.

Matt

every time the points open they spark, every spark leaves a little carbon burn, and it up and the you go.

Thanks for the responses so far guys. After I had points fail on a 4 cylinder 914, I replaced them with a Pertronix unit and never had an issue again. That was back in 1999. However, when I read aboutthe Pertronix on this site, you would think the devil himself is selling them to us.

Maybe it's time to try that route again.

Dion

Just to add some physics geek ramblings to what's already been said....

The coil (a transformer) is used to change from low volts/high current to high volts/low current. The job of the points is to turn that high current on/off. But problems occur in that hazy region between on and off, i.e., you have a resistance that's not zero, not infinity. In your case, my guess is that the bare metal sat for years and got a little bit of rust/crud on it. If you run lots of current through a resistor (the rust/crud) you basicaly have a tiny toaster oven. Short pulses of extreme localized heat, which (I'm guessing) can actually increase the pitting.

Another issue is what happens in the transformer. You dump a lot of energy into it, and that that energy has to go somewhere. Usually it comes out in the form of current arcing across the spark plug gap. The spark itself is electrical energy turning into heat. But if the plug wires are disconnected, the spark doesn't happen, and all that energy is still stored (in the form of a magnetic field) inside the coil. When the points start to open, the current "wants" to keep flowing (due to the inductance of the coil), and as a result a huge voltage builds up across the primary. So, even though the points are only supposed to see 12 V, as they open up the voltage is getting much, much higher. If not dealt with in some way, an arc will form, and this is gonna cause some damage. How to prevent this ? Well, the trick is to add a capacitor (aka "condenser"). The capacitor allows current to flow through it for a short amount of time, which prevents the dangerous build-up of high voltage across the points. So a bad or disconnected condenser is gonna show up as points getting toasted.

I'd have to agree that swtching to some kind of optical system is the way to go, unless you're trying to keep it strictly original. No friction, no arcing, no rust.

My Crane IE failed me last year. I installed points untill I get a new IE. So far this year, I have had points fail on the freeway two times and had to be towed.

I remember reading somewhere that there is some sort of ointment you can apply to the points to keep them from failing so quickly.

Does anyone know of such ointment and how well it works?

pertronix = 70 bucks
compufire = the same
crane xr7000 = 100 ish (too much hassle)

buy a pertronix and keep spare points in your box if it dies....

Ab-sa-freakin-lutley.

I got pertronix on both the MGA and the 914. Love it. Don't know who is giving the impression that the Pertronix is bad but donna listen to 'em.

The only people that I know that have had problem with the Pertronix are those that improperly installed it (how the hell you do that I have no idea) or left the key on and fried it (which you can do with points as well).

Go spend the 70 georges... you thank yourself later.

Points should be cleaned, greased and reset every year. They can also be filed. Use only bosch points as the contacts are tungsten.
If you are using a coil that isn't compatible they will burn-up in no time or the fiber block will melt.

On the Pertronix I've had several customers experience failures so I don't sell them anymore. All swear they didn't leave the ignition on.
I had a new compufire fail in my bus on my PEI trip this summer, about 1000 miles from home.
Luckily I had a Mallory in my tool box, it was intended for my bug engine, but it's staying on the bus.

Now, if you can just figure out that your electronic ignition is actually failing........(see RRC 2005 thread).

AFAIK, there are no electronic points-replacement items for the original
914-6 dist (Marelli). By now most people seem to have gone to the bosch,
though.

I have optical on my marelli (thanks to the Crusty one many years ago
sending me a proto), just checked my timing after almost 2 years, still
holding steady!

I sold the Marelli long ago and replaced it with a nice little Bosch 169 008 unit. I'll probably order the Pertronix unit tomorrow and keep this set of points in the box for a spare. Took her out for another spin tonight, and she ran great with the 'cleaned' points.

Again, great feedback guys.

Dion

FWIW, I have a Crane XR-3000. IIRC, when I was researching this, the advantage of using it over Pertronix and some other units was that you could use a coil without an internal ballast, which gave you a hotter spark, improving combustion at lower engine speeds (e.g. better idle and driveability). I used a Crane PS60 coil. Mine has been totally reliable since the install, I never had to adjust it at all after the initial setting.