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Plug gaps for MSD systems

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Old 03-21-2008, 11:47 AM
  #41  
Jim_Harrison
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I have a complete MSD system, coil 6AL and tach drive distributor. .045 gap on AC plugs, for 5 years or so, never a problem.
Old 03-21-2008, 11:49 AM
  #42  
V-Rod
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If you like bikes and have never ridden one you need to check out the v-rod, It is very quick and sits' good has low cg with gas tank under the seat and aslightly forward controls position my 74 yr old father loves to ride it because it's easier for him to hold up than his other bikes
Old 03-21-2008, 12:04 PM
  #43  
Bob in Dallas
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The true engineering reason for the short duration, high energy spark is to provide more absolute power (Joules=Watts x time) in a shorter pulse. The shorter pulse provides the energy required to fire the mixture and does not erode the electrode as much as a low energy, long duration spark.

The difference in a standard point ignition and a HEI in time is from about 1200 milliseconds (.12 Sec), a spark which continues long after the piston has moved from optimal firing point, even at low RPM's, to about 150 microseconds (.000150 Sec). This provides a high energy spark, precisely timed to ignite the mixture at exactly the proper timing. This is required for all emission control systems.

GM didn't change the system design from a cheap system to a more complex costlier one for no reason. Durability requirements combined with emission level requirements drove the technology.

Thank technology and computer controls for 2008 Corvettes in stock form being faster , more reliable, quieter, and more efficient than any of the famous big block cars, even the famed L-88.
Old 03-21-2008, 02:06 PM
  #44  
69427
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Originally Posted by V-Rod
Yes I have a 2000 V-Rod and I think it runs on a mag too. I has a stage one screaming egale kit and will hit 60 in !st. I am not trying to pick sides here I just think things got out of hand last night
I am personally happy that you are satisfied with the performance of the V-Rod. This engine, among others of course, shows that an inductive ignition system (a respectful and friendly correction ) works quite well with a high compression, high rpm engine. A capacitive discharge or multiple spark system rarely is necessary for most engines.
Enjoy the bike, and please be safe!
Old 03-21-2008, 10:07 PM
  #45  
VCuomo
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Originally Posted by Bob in Dallas
...The difference in a standard point ignition and a HEI in time is from about 1200 milliseconds (.12 Sec), ....
120ms = .12sec (not 1200ms; 1200ms = 1.2sec).
Old 03-21-2008, 10:25 PM
  #46  
VCuomo
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And here's what MSD has to say about their 6 series box:

CAPACITIVE DISCHARGE
The MSD 6 Series Ignitions feature a capacitive discharge ignition design. The majority of stock ignition systems are inductive ignitions. In an inductive ignition, the coil must store and step up the voltage to maximum strength in between each firing. At higher rpm, since there is less time to charge the coil to full capacity, the voltage falls short of reaching maximum energy which results in a loss of power or top end miss.

The MSD Ignition features a capacitor which is quickly charged (within one millisecond) with 460 - 480 volts and stores it until the ignition is triggered. With the CD design, the voltage sent to the coil is always at full power even at high rpm.


MULTIPLE SPARKS
The MSD 6 Series produces full power multiple sparks for each firing of a plug. The number of multiple sparks that occur decreases as rpm increases, however the spark series always lasts for 20° of crankshaft rotation. Above 3,000 rpm there is simply not enough "time" to fire the spark plug more than once, so there is only one powerful spark.
Old 03-21-2008, 10:29 PM
  #47  
JustinD
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Oh dear, this one should have stayed dead. Shame on everest for digging it up.
Old 03-21-2008, 10:45 PM
  #48  
MotorHead
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I have had mine at 35thou since I put it together. I have a 6al box, I tried 45thou and it didn't start. Not sure why, or if was just a fluke but I regapped them to 35 and it started right up. Maybe 11:1cr and 230psi cranking pressure has some thing to do with it I don't know
Old 03-21-2008, 11:29 PM
  #49  
FB007
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Originally Posted by V-Rod
I know what magnetoes are ( to some extent ) they produce their own current for one ie don't need battery to run, they are a back up system yes but they also contribute to preformance. if you have ever been in a small plane when the pilot did his runup test you would have noticed an rpm drop when he checked his mags. I don;t know anything about ignition system or engines. my point was that if MDS systems are being used by the big boy their products are sound. my engine builder has 30 yrs exp and that's the system he used. my second point was this is not the place to prove who is the smartest. This fourm is for discussion not a p***** contest.
I am not having a pissing contest. I merely corrected your untrue statement. My other point is that the "big boys" have a different system than the $200 speed shop special.
Old 03-21-2008, 11:29 PM
  #50  
FB007
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Originally Posted by MotorHead
I have had mine at 35thou since I put it together. I have a 6al box, I tried 45thou and it didn't start. Not sure why, or if was just a fluke but I regapped them to 35 and it started right up. Maybe 11:1cr and 230psi cranking pressure has some thing to do with it I don't know
Correct
Old 03-22-2008, 01:47 AM
  #51  
V-Rod
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FB007,

I was not accusing you personally and I am sorry if you took offence. As you can tell I know next to nothing about engines or electrical systems. So whats wrong with a 6al box and is there anything better I could use to run my MSD distributer? Thanks and again I apoligise
Old 03-22-2008, 11:35 AM
  #52  
brngrhd
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Originally Posted by V-Rod
Yes I have a 2000 V-Rod and I think it runs on a mag too. I has a stage one screaming egale kit and will hit 60 in !st. I am not trying to pick sides here I just think things got out of hand last night
same here but i have a 2004 got to love v-rods and corvettes. i bought an msd setup because i had points which sucks and needed to upgrade. i was going to run an HEI setup but want to run nitrous so that made a good reason to run the digital 6 box where is has two step rev limit and auto retard for nitrous activation.
Old 08-19-2017, 10:30 AM
  #53  
Charlie Buttacavoli
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Default Multiple sparks = good.

Since the plug fires when current to the ignition coil is cut or interrupted,doing this multiple times during a given ignition period will result in a more thorough fuel mixture burn and help lower Nox2 levels along with a boost in performance resulting from the better system efficiency.Firing occurs every time the coils magnetic field collapses.Perhaps a better look at ignition timing should be done in concert with adjustment of plug gap.Take it to the track and make a bunch of passes.See what you find out.
Old 08-19-2017, 04:34 PM
  #54  
Mako72
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I have the same setup as you do except on a SB. I run Champions and have set the gap at .045 for years.



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