Been off the forum lately but I am back with a better motor. Took about 1.5 yrs to get the $$$ but the 350/350 is now a 383 Stroker.

I did a search and did not come across anything about electric ignition over stock points.

Other than not needing to mess with dwell or timing what other advantage does electonic ignition give you? I am looking at the Pertronics Electric Ignition II.
I am not looking to replace the whole distributer as I want to keep my mechanical tach.

 

You usually can also count on a more powerful spark which will possibly buy you some more power because you can play with the timing...

 

That's about the last thing you could expect.

Electricity is passive and the spark will be exactly as strong as it needs to be to jump and sustain across the gap. No more, no less.

The only time you may benefit from a conversion is if you have cylinder pressures higher than the current ignition's voltage can reach or if you have a poor tuneup. Of course, there are no longer any points to adjust so you're off the hook for that.

 

I put a Crane XR-I in mine. It's a easy swap from the points, but also gives me an adjustable rev limiter. I think it was around $65. So far I give it
Dave

 

The electronic conversions do not increase spark intensity or secondary voltage. All they do is provide an electronic trigger to the coil primary circuit as opposed to a mechanical trigger (points). This has no effect on secondary voltage or spark intensity, and therefore has no effect whatsoever on performance or power.

 

Points never left anybody stranded on the side of the road. At least anybody with a screwdriver and a matchbook. LOL Joe

 

I agree!!!!

 

It's not a 'simple' trigger but rather more like a 'discrete' switch. vs a mechanical contact. It makes all the difference in the world....

The discrete like switching and it's affect on saturation has considerable affect on the amount of voltage the coil makes particularly at lower RPMs. In short - higher voltage at lower RPMs.

True. But it allows for wider gaps and can thus improve emissions if that is considered a measure of performance and perhaps under some circumstances may improve power as well.

It also extends plug life by 10 fold or better and makes tuneups a rarity compared to points based system whereas points begin wearing (and affecting dwell, pitting etc) from the first instant they are used.

 

I'll have to disagree with most on this one (even Lars).

The Pertronix Ignitor contains a microprocessor controller which allows the secondary voltage to be used more efficiently by allowing greater buildup of energy in the coil. It has 3 times more available energy between 3000-5000 rpm, and nearly doubles available plug voltage.

With higher voltage available at the plugs several tweaks can be invoked: the gap can be increased creating a larger spark, the compression can be increased or supercharging can be employed because the spark can jump the gap even though there is more resistance from the heavier mixture, and finally the duration of the spark is much longer which improves combustion efficiency.

69Sting would even get more boost if he went with a CD system in addition...


http://www.rodandcustommagazine.com/techarticles/73738/


If this were true, combustion efficiencies of modern engines would be the same as they were 50 years ago. This only describes the minimum condition for a spark. "no less" - Yes, "No more" - wrong. More current increases the intensity and duration of the spark.

Triggering a spark across a spark-plug gap requires both voltage and amperage. Voltage is the electrical pressure that “pushes” the current (amperage) through a conductor.

The amount of current flow combined with the voltage plays a big part in an efficient combustion process. The more current pushed across the plug gap, the better the chance for more complete combustion.

 

Well I'll be damned! They up and when and changed the laws of physics while I was asleep!

I guess I better crack a book open and study up on that durn induction, capacitance, and that flow of electrons through a conductor stuff and see what's changed.

 

Musta slept right thru class.

Z-man is correct - it wasn't just for kicks and giggles that the manufacturers switched to electronic back in the 70s - higher voltage, wider plug gaps and sustained mileage w/o tuneups were what they needed and electronic ignition was their ticket. Vague schoolboy memories aside - any number of SAE white papers or basic automotive theory on IC ignition systems corroborate Z-man's post.

 

I can understand how you might get a stronger spark because the coil has more time to charge up, but it's not that much more. If you want to see a real change install a CD ignition.

 

I resently replaced my dualpoints dists (no vacuum canister, no rpm limiter) to a all MSD system (Balster2, AL6, Superconductors, and Corvette ProBillet distributor with mechanical tach drive).

I do not understand too much of the technical stuff but the car acts totally differently than previously. It idles much more steady (previously tach jumping up and down doing 150 rpm scale - now max 50 rpm scale). I used to have the idle speed set at 700 now 625 seems to be ok. The engine used to stop sometimes after hard launch and braking - not anymore. And it responds with clearly stronger kick in low rpm 1000-2500 - I konow the added vacuum advance must be important here not only CD and multiple sparks. Overall there is never a going back for me here. And for the rpm limiter and mechanical tach drive were a must in the new setup for me.

 

There's a big difference between an electronic trigger system (like UniLite or Pertronix) that replaces points and an actual HEI or capacitive discharge system. PerTronix points replacement is not an HEI system. There is no question or argument that HEI and capacitive discharge (MSD) is an advantage over a stock points type system.

As noted by others above, in theory, you can get a slight advantage in coil saturation with an electronic trigger. You also eliminate points bounce, rubbing block wear, and contact point pitting, thus maintainig constant dwell. This would, in theory, result in improved performance. However, I have done actual back-to-back dyno testing on standard points versus 2 different brands of electronic conversions (without capacitive discharge enhancement like MSD), and I can tell you that the measured results are indisputable: There is absolutely no difference whatsoever in the horsepower and torque between a stock points system and the electronic conversion as long as the advance curve is not altered. However, since the electronic conversions eliminate the rubbing block friction, the advance curve quickens up slightly, and this actually will produce a slight measurable increase in bottom-end torque. The same result can be achieved by re-curving the stock points distributor.

I did this testing on the Westech engine dyno with Matt King from Hot Rod Magazine - I have photos of the event. Testing was done on a 302 Ford with AFR heads. The points distributor used for the testing was the one out of Matt King's Fairlane that was parked outside in the parking lot (we pulled the MSD distributor and ignition system out of the test engine and did the points versus electronic testing using the stock points distributor).

Theory is neat, but the measured results don't lie: There is no difference in measured power output of an engine between points and electronic trigger conversion. Absolutely none.

MSD, however, is a different story...

 

I have a set of points that trigger my Crane HI6 box (CD ignition). It has worked extremly well and a set of HD points allows me 7000 rpm with no missfire at all. I did recently check the points and after only about 5K miles the point gap had gone from .020 to almost nothing. The car still ran fine but I was in there for something else and this was not what I wanted. Seeing the points are just an on/off switch the gap does not affect performance or operation but before long there would have been no gap and nothing to trigger the system. I just adjusted them and all is back to normal so I will just check them more frequently.

 

Thank you Lars, an excellent post. Hopefully the old myth about the pertonixs POS will go away.

I've never understood why people trip over each other in a rush to install a device that introduces a failure mode (sudden death) that does not exist in the standard system .

 

Well Hells Bells, I'm sure not going to debate you folks here,all I can say is I stay with points on cars that came with them and HEI on the 75+ cars.


Gary

 

As a little added sidenote:

On the last 2 Tuning for Beer Tours (Virgina and Chicago), I have removed electronic trigger conversion systems and converted distributors back to points with a resulting improvement in hi-rpm power, off-idle throttle response, and increased seat-of-the-pants torque "feel." After the conversions, the owners were given the option of keeping the points or going back to the electronic conversion. In every case, the electronic conversion has ended up in the trash can. If you want one cheap, contact Eddie in Chicago: his trash can has a couple of complete systems in it...

 

Why not have the best of both worlds? I use an electronic CD system (Mallory HyFire IV) triggered off the points on my '64. Using this system, the points only serve to trigger the box and carry no current. Hence, they don't arc, burn, or pit and stay in adjustment. Additionally, the box sets the dwell so point adjustment becomes less critical. (The points can be really out of adjustment and the car still runs fine. But if I disconnect the box, the car will not run until the points are brought into spec.) If the box has a problem, within 1 minute you can by-pass the system using the supplied jumper and run off the points.

When Lars did the tune-up on my '64, it ran great during an initial test run. Once Lars did the tune-up, it died each time the secondaries kicked in. The Mallory box was by-passed with the jumper and the car ran better than ever. I cleaned the fuse to the Mallory (was very corroded), reconnected the system, and it has not had any further problems. I guess that the corrosion on the fuse kept the box from receiving adequate current to fire through the increased cylinder pressure of the tune-up.

 

So, If I have read all this wounderful info correctly.
To just replace the points with a Electric point replacement is not a way to go unless you hate to set dwell.

If you change from stock go straight to the 1 of 2 CD systems. No points, or Points with a jumper for back up.

I was looking at going MSD but couldn't figure out what components I needed. I see VESA has this already figured out. Now to to get some pricing and see if I can get it done yet this summer. (I hate changing distributers).