To much spark??

[f_inscreenname]

I am sitting here looking at my (favorite) Northern Auto Parts book at coils. The coil I have is a Accel Super Stock (35,000 volts) I thought it was pretty hot but now I see they have 40,000 and 45,000 volt coils. What would the benefit be of running a even hotter coil? With a hotter spark could I get better combustion out of the gas they pass off today as 93 oct?

 

[rodbolt]

Re: To much spark??

none<br /> if ya put a Kv tester on yours you may see 10 to 12 Kv at WOT and 7-10 at idle.<br /> the new 250 yamahas have a zener diode in the secondary output to force the firing Kv to 34 Kv minimum.<br /> you can instal a jillion volt mega bux coil but if all thats required to jump that 30-40 thousanths gap under compression pressure is 7 Kv thats all you will ever see.<br /> a stock coil on an old points system could go as high as 30 kv if something was amiss and the ign generating part was in good shape.<br />I would rather spend my cash on an MSD box to insure a good burn.<br />higher octane burns slower so if ya spark it multiple times it keeps burning.

 

[f_inscreenname]

Re: To much spark??

No points. Pertronixs upgrade. If that makes any difference?

 

[Dunaruna]

Re: To much spark??

It would allow you to open the sparkplug gap, fatter zap equals better burn but to 'feel' any benefit you would need to play around with the timing.

 

[DJ]

Re: To much spark??

What rodbolt said.<br /><br />Plus.<br /><br />

It would allow you to open the sparkplug gap, fatter zap equals better burn but to 'feel' any benefit you would need to play around with the timing.<br />

True, however your compression ratio and fuel amount really determine how much voltage you need. It will only use what it needs.<br /><br />Many modern automotive engines have the capability of exceeding 100 KV.

 

[rodbolt]

Re: To much spark??

all that petronix is is a switch.<br /> just like points.<br /> it has noting to do with secondary coil voltage.<br /> it simply turns the current on and off in the coil primary circuit.<br /> petronix wont to anything a well maintained points set will do.<br />electricity is just plain lazy, like me and bass .<br />it will take the path of least resistance time after time.<br /> however once I get my hands on some of the 250 yam coil in plug cap parts I am going to modify it to accept a low voltage point setup as a trigger. that coil wont fire below 34Kv due to the zener diode on the secondary circuit.<br />draw back is the cost about 140 each.

 

[Dunaruna]

Re: To much spark??

Yeah but..................the pert switches more efficently than the points, especially at high rpm. It shuts down/energise the coil with more precision. <br /><br />A coil will only deliver what is needed to complete the circuit, if the plug gap is openned, more voltage is required to jump the gap and find ground, compression is the hurdle. <br /><br />More voltage out the tower means that hurdle can be jumped more easily.

 

[rodbolt]

Re: To much spark??

yep but at RPM's below 4500 you wont notice the electrical noise generated by points in engine performance, in fact my 455 olds regularly spun 6500 with a set of points and when converted to electronics my time slip showed no speed increase. however the maint fell to nothing.<br /> and in a boat,especially one that has long periods of inactivity, petronix is better than points but not as good as a true electronic system.<br />its absolutly amazing the technology change in the past 35 years.<br /> I started this gig back in the mid seventies.<br /> points,caps and rotors lasted 10,000 miles maybe, less if the distributor shaft seals wore or the crankcase vent system plugged.<br /> carbs leaked shafts wore and accelerator pumps failed often.<br /> a set of plug wires might go 20K miles before failing.<br /> a modern EFI engine can go an easy 100K miles with nothing.<br /> I see it all the time.

 

[newport dave]

Re: To much spark??

I have to disagree on a few points here. <br /><br />

you can instal a jillion volt mega bux coil but if all thats required to jump that 30-40 thousanths gap under compression pressure is 7 Kv thats all you will ever see more energy in the coil will not be a benefit.

You will see a benefit in the form of a longer firing time. It's not all about firing voltage.<br /><br />

all that petronix is is a switch.<br /> just like points. it has noting to do with secondary coil voltage. it simply turns the current on and off in the coil primary circuit. petronix wont to anything a well maintained points set will do.

An electronic switch is much faster. The faster the switch, the faster the rate of collapse of the magnetic field in the coil primary, and the result will be a higher induced voltage in the secondary winding.<br /><br />The real benefit of an electronic ignition comes from it's ability to use variable dwell for current limiting. That eliminates the need for a ballast resistor or resistor wire and allows using higher coil charge current. More current means a faster charge time. At higher RPMs a fast charge time is critical.<br /><br />Dave

 

[rodbolt]

Re: To much spark??

ok newport<br /> place a well maintained points set up on your fancy machine and then a well maintained electronic. limit the RPM to 5K and tell me the difference.<br /> we never saw much either on our dyno or our fancy snap on rig.<br /> what I am saying is there is no real performance differene in the ign system from a well maintained points or a petronix below 5K. later model electronic systems show a bit of a gain.<br /> the electronic switch can be faster or slower depending on any clipper or clamper circuits and any base biasing on the transistor.<br /> thats the whole beauty of electronics, it can be tailored as you drive and points cannot.<br /> and the maint required on an electronic system with a dry coil is very minimal, points will usually not make a season.<br />or if they do its iffy.<br /> but some of the latest generation TCI ignitions are killer.<br /> but so far the petronix is just a switch with no variable inputs not outputs.<br /> its a hall effect device with a transistor, the coil still requires an internal or external resistor and a coil with less than an 8 amp current draw for V8's.

 

[f_inscreenname]

Re: To much spark??

Alright guys , this is the deal. Most here already know I am running a pretty hoped up motor( motor build sheet). About 10.5 to 1 compression etc, etc. 360ci Mopar. I built the first version of the motor a couple years ago I have been chasing a “timing knock” problem ever since. The motor has been out 4 times in the last 6 years for major upgrades and every time it goes back I still have the “timing knock” somewhere in the throttle range. I have tried a couple different distributors, a new Mallory duel point, a couple rebuilt used versions and a new Prestolite with a Pertronix kit in it, a couple of coils and everything else has been changed over time and still have the “knock”. I can move it to a different RPM by resetting the timing but it is always there somewhere. It is not like a clanging cow bell or anything but for someone who has done everything to make a motor perfect each ping is a stab in the neck. <br /> I have also tried octane boost with no help. <br />The reason I bring all this up is, when I took the boat out of hibernation this spring I put new plugs in it and instead of gapping them at .035 and adding the .005 the kit says to do I only gapped them at maybe .037 and on my first ride with half old and half new gas I would only get a ping here and there (like every 10 to 15 seconds) when at WOT.

 

[newport dave]

Re: To much spark??

Originally posted by rodbolt:<br /> ok newport<br /> place a well maintained points set up on your fancy machine and then a well maintained electronic. limit the RPM to 5K and tell me the difference.

Sounds like a good time to me. I will post results when complete.<br /><br />Dave

 

[drvred]

Re: To much spark??

The higher the compression the smaller the plug gap. My 14-1 motor uses .025 and runs great.