What Brands Make The Best Quality Points Ignition Components?

[raygreenwood]

[modok]

Thanks for that. I'm afraid I just haven't paid much attention to which brand is which, and I rarely bought any, as the engines and cars I bought over time tended to yield large supplies of new and used bosche points. Soon I'd like to do a test of which models have the least float. Current handling is no longer a concern

[raygreenwood]

[modok]

Yes, using a tfi module to handle the current, three years now.
Wish I had investigated the bounce when I had the chance, but lets say it will be a winter project. I want to recreate my bench testing setup with oscilloscope, tach, drill to drive distributor, variable coil load, ect, and try different points sets, different gap setting, and try lightening the points and see what happens. Only one way to find out!!

[Sirius_Doctor]

Are there any thoughts on condensers for the 412? I purchased a new condenser from Auto Atlanta. Unfortunately the 'short' wire was not long enough to mount it on the proper side of the distributor. Although I made it work, the condenser failed in about 3 months. It is Bosch branded and made in Turkey. I have never had a condenser fail, much less in 3 months. Is anyone aware of OEM quality condensers with the proper length short wire made for the 412 stock distributor?
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Never assume that loud is strong and quiet is weak.

[Fred Winterburn]

I really don't think that the small amount that points bounce affects the overall dwell, matters much with a low revving 4 cylinder. Assuming the TFI module has no protection against points bounce, it shouldn't matter. If there is dwell extension with the TFI (is there?) then it might affect the dwell extension circuitry without bounce protection. Either way, since the coil has to take some time to saturate, the small amount of energy lost when the points open on the bounce won't result in a spurious spark and the only loss of energy is that brief moment while the points are bouncing. Sure it gets worse with rpm, but only at very high rpm, will it start to be a significant portion of the available dwell. I can't see it being a problem at normal redline on a VW. Maybe on a race engine with higher rpm potential.
I think too that most people do not seem to know that there is a difference between points bounce and points float. Points bounce starts right at idle and if you think about it, there is no damping mechanism for the spring, so of course they will bounce open at least once on closure. A stiffer spring will help but it won't prevent it. With a CD ignition triggered by points, it is imperative that there is points bounce protection built into the trigger circuit, because otherwise there will be unwanted sparks every time the points open on the bounce (since the energy for the spark regenerates itself very quickly by the CD power supply for one, and secondly the discharge capacitor is charging even when the points are open once the spark event is over).
Points float is another animal and only occurs at extremely high rpm. You probably can't reach points float on a 4 cylinder even with a standard spring. Points float results in a very damaging floating of the points under very high rpm such that they might not even close every time, and the timing becomes quite erratic. It puts a huge strain on the moving arm of the points and I've broken a couple of sets on the test rig when I let it rev to over 12 thousand rpm with the 8 cylinder Ford distributor. To recommend blue streak as Ray has, is good if you can find an old set. I don't think they are manufactured anymore. I have a set of those in the test rig right now and I haven't been able to break them. The moving arm is designed better and is stronger and lighter than the cheapo sets I was using. Putting it in perspective though, in real life nobody would be revving that high. Fred

[raygreenwood]

[modok]

[raygreenwood]

[Fred Winterburn]

If it's double firing, that tells me there is no anti-bounce circuit and the TFI has dwell extension. Points alone won't cause double firing on the bounce because there isn't sufficient time to build up current in the coil when the points close and then immediately bounce open. For a second spark when the points bounce, the coil must have been getting current prior to the points closing. I presume what must be happening, is with rising rpm, whatever filtering the circuit may have, no longer works with the increased bounce, and the phase in of dwell control results in a second spark. The filtering is probably minimal and only meant for a magnetic trigger and not points bounce. The interruption of dwell is normal for points bounce, but the second spark certainly isn't. Fred

[j-dub]

Since we are talking about point bounce...

I am also only using points as a trigger.

What can be done to make points trigger more reliable? I have lowered to points gap from .016 to .012 as well as bent the spring a bit to increase the pressure.
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1957 Oval rag
"POLICE STATION TOILET STOLEN ... Cops have nothing to go on."

[modok]

run some current through them to keep them clean.
MSD for instance, uses 40 ohms resistance from points wire to +12v, so it runs 1/3 amp through them. This also allows the condenser to be left in place.
More reliable? They are as reliable as the tides. I don't see how you could make anything more reliable

In my case the bounce is not causing any perceivable problem in how the engine runs, just a little spark during the exhaust stroke when I'm overrevving it, and still works better than points alone! But once you know about something....then the gears start turning, start wondering. I could see how it could certainly upset a computer!

[j-dub]

Okay, maybe reliable was not the right word.

Let me reword my question, what can be done to mitigate points bounce at higher RPMs?
_________________
1957 Oval rag
"POLICE STATION TOILET STOLEN ... Cops have nothing to go on."

[raygreenwood]

Point bounce rarely creates a "double fire". It creates a missed fire. Its just too fast. Whatever short,current saturation has occurrs in that millisecond of bounce dumps the coil and the next true cam ramp has no voltage.

A double bounce effectively cycles the coil at maybe twice the current speed. So if you are at 4400 rpm engine speed....it effectively sees 8800 rpm equivalent cycle rate. Its a miss not a double spark.
Ray

[modok]

Filtering the points signal can be done with a analog filter circuit, or it could be done digitally too with modern technology. Ignition boxes and tachometers are having no trouble with it, except for a few cheap ones I came across, but they were crap anyway.

At worst case with some filtering schemes you get a bit of delay, which is partly why a lot of ignitions systems the trigger signal is 90degrees btdc, because it just makes more sense that way if you think about it.
Do you need to do that? probably not. I am sure Fred W. will tell you even using rather old and simple methods we can turn these things 9,000 rpm no problem with a good CDI. If your not partial to CDI, inductive ignition boxes also existed from Jacobs, Mallory, MSD and others, which would have been pretty much a GM hei module and a few circuits in a fancy box 9maybe some were!), but I don't think any are currently made today. All antique now.
Mainstream has moved on from points, but.... a lot of what's on the market is "hobby quality", not as good as they made when it really mattered, so I prefer to steer clear of it. OOPS... not that I want to start that debate, but, that's the main motivation here, if it wasn't clear.

[raygreenwood]

[Erik G]

[slalombuggy]

When I was racing my buggy, I would use points made for Rabbits in my 009 distributor. They had a stronger spring and would resist bouncing much better.

brad

[mikedjames]

Over here in the the UK , I have seen a set of Bosch ignition parts as badly made as the Chinese stuff that came in a cheap distributor.

And every part of that Chinese distributor was in some way wrong. Either badly built, not interchangeable, or it wore out fast.

On the other hand , the Beru branded stuff we can obtain still seems high quality.
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1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
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[raygreenwood]