MSD Dead - Help with direction please

[ToddMcF2002]

Well... this isn't really an anti MSD thread. This is a "I don't want to spend another $300 on a performance ignition I don't really need" thread. If you run MSD for track purposes and you like it knock yourselves out. Run points and you are happy or an Orange box and your happy that's fantastic. What would Uncle Tony say? Break out the feeler gauge!

 

[RJRENTON]

Well... this isn't really an anti MSD thread. This is a "I don't want to spend another $300 on a performance ignition I don't really need" thread. If you run MSD for track purposes and you like it knock yourselves out. Run points and you are happy or an Orange box and your happy that's fantastic. What would Uncle Tony say? Break out the feeler gauge!

Personally, i don't think about anything "Uncle Tony" has to say.....about anything....including points vs Mopar Orange Box ignition vs MSD ignition vs ??? ...or his view on investing, state of the economy, or life in general. As far as personal vehicle ignition or fuel delivery methodology or which beer is best....that's entirely up to the owner....
BOB RENTON

 

[Geoff 2]

Simplest, easiest fix is to use a GM HEI 4 pin module. Under $25 at Summit, or you can get one for more $$$$ that has an adj rev limiter.
Less wires than MSD box, less space used. You would need to check if your coil is suitable, factory coil is ok. The GM system is better than the CH system because it has adaptive dwell, & some modules switch more current.

 

[Don Frelier]

Simplest, easiest fix is to use a GM HEI 4 pin module. Under $25 at Summit, or you can get one for more $$$$ that has an adj rev limiter.
Less wires than MSD box, less space used. You would need to check if your coil is suitable, factory coil is ok. The GM system is better than the CH system because it has adaptive dwell, & some modules switch more current.

He already has the plug for the Chrysler style ignition? How could it be easier.

 

[ToddMcF2002]

Now that I've gone the Chrysler direction, should I remove the MSD billet distributor and source one with vacuum advance? I'm thinking yes but wanted some opinions. I figure the gas saving will pay for the distributor.

 

[ToddMcF2002]

So its an MSD 8546 which appears to be good quality so I think I'll keep it for now. I pulled the distributor because its pretty nasty inside and the MSD curve springs look like they are about to fail. I'm planning to run the light blue light silver springs & black bushing. Any disagree? Also I did mark the housing and rotor orientation but I'm assuming for the internal shaft itself 180 degree orientation does not matter?

 

[Don Frelier]

Personally I would run a vacuum advance unless you have a Racecar

 

[ToddMcF2002]

Personally I would run a vacuum advance unless you have a Racecar

I agree but I can't seem to find an MSD "mechanical" distributor with a vacuum advance unless I switch to a "read to run" model with a built in controller that will force me into yet another wiring customization. Can't win. Are you aware of a magnetic pickup vacuum advance distributor that will allow a reliable curve setup? The MSD curving is extremely easy.

 

[RJRENTON]

So its an MSD 8546 which appears to be good quality so I think I'll keep it for now. I pulled the distributor because its pretty nasty inside and the MSD curve springs look like they are about to fail. I'm planning to run the light blue light silver springs & black bushing. Any disagree? Also I did mark the housing and rotor orientation but I'm assuming for the internal shaft itself 180 degree orientation does not matter?

View attachment 1274376 View attachment 1274377 View attachment 1274378 View attachment 1274379

IMO..... Your first pix looks exactly like a GM/Delco distributor's advance mechanism. When I use to experiment with GM stuff, I always interchanged the advance weights (as their "tails" had different angles) that affected the rate and amount of advance (at any given distributor RPM) combined with spring tensions (and limiter nushing) to create a truly customized advance curve. The MSD distributor looks to have copied the GM design. Can't really see the pick up coil assembly.... You may consider using some of the GM parts IF you're trying for an exact advance curve to maximise your application. Judt talking out loud.....
BOB RENTON

 

[ToddMcF2002]

Good drillable spot? Anything to be concerned about on the other side?

 

[RJRENTON]

Good drillable spot? Anything to be concerned about on the other side?

View attachment 1274463

Maybe the heater core????.....Depends on the screw length....PLUS REMEMBER THE SEPERATE GROUND WIRE ATTACHED TO THE ENGINE BLOCK.
BOB RENTON

 

[Don Frelier]

I would face the plug on the other side.
Can't comment on the holes.

 

[ToddMcF2002]

I just drilled it tons of open air behind. Flip the unit you mean so the plug is on the inside? Bob what was that ground comment I didn’t follow. I know the case needs to be grounded….

 

[Don Frelier]

The firewall should be grounded to the block. It looks like it is.

 

[ToddMcF2002]

The firewall should be grounded to the block. It looks like it is.

I have a little extra ground wire you can see going from the head to the voltage regulator. Many moons ago I learned from the apron mounted solenoids on Fords that a little ground insurance is a good thing

 

[RJRENTON]

I just drilled it tons of open air behind. Flip the unit you mean so the plug is on the inside? Bob what was that ground comment I didn’t follow. I know the case needs to be grounded….

Sorry for the confusion on my part, for not explaining the ground connection better. The ignition module ABSOLUTELY needs to be grounded, either to the firewall or from one of the ignition module's mounting lugs to somewhere on the engine block (preferably) with a separate wire. The wire could be a #12 or #14 stranded copper wire with a crimped on lug to accomodate what ever size bolt you sre using. The transistor on the outside of the module's case, switches the coil's primary winding current to produce the spark. IF the ground connection at the module is inadequate, the spark will be erratic.....just insure the module is securely grounded....either at the firewall or thru a separate wire or both. Just my opinion of course.
BOB RENTON

 

[threewood]

IMO....I believe that the Pertronix system and maybe the Mallory system, are not capable of multiple spark discharges as there are not enough componentry present to do this. I speculate, as I've not seen the schematic diagram representing system's internal components....not the installation wiring but the internals of the module. The Pertronix system uses a Hall Effect switching transistor and a magnetic pick up coil all in one device to make-break the coils primary current creating the spark. There is not enough physical space to allow for a capacitor to create multiple spark discharges. The pick up coil assembly in the distributor is a simple pulse generator, that furnishes the switching module the off (breaks coil current and produces the spark) - on (turns on coil primary current or recharges the coil for the next cylinder) information to create the spark. That's the basic mechanism of how....the difference is the hardware used by the different manufacturers to make this happen.
BOB RENTON

Pertronix Ignitor III is multi spark

 

[RJRENTON]

Pertronix Ignitor III is multi spark
View attachment 1274632

Thank you for the information....but....I still would like to know HOW the multiple spark discharges are accomplished without a capacitor or what is the speed of the switching transistor to turn the coil off to create the spark then on to recharge the coil for the next, or continuation, of the spark discharge. And just how many sparks that can occur per each cylinder at say 5000 RPM? Just seems to good to be true.....inqiring minds want to know....
BOB RENTON

 

[Geoff 2]

I also wanted to know & emailed Pertronix asking the same questions. Surprise, surprise, no answer. If it was actually possible, you would expect other companies to copy it because multi spark would be a sales plus.
I emailed Dr. Hugh Holden [ see below ] for his thoughts & he couldn't explain it either....
www.worldphaco.net

 

[RJRENTON]

I also wanted to know & emailed Pertronix asking the same questions. Surprise, surprise, no answer. If it was actually possible, you would expect other companies to copy it because multi spark would be a sales plus.
I emailed Dr. Hugh Holden [ see below ] for his thoughts & he couldn't explain it either....
www.worldphaco.net

WOW !!!!! THANK YOU VERY MUCH FOR THE LINK.... THE SUB CATAGORY DEALING WITH CDI IGNITION SYSTEMS AND THEIR FUNCTIONALITY IS SIMPLY OUTSTANDING....and complete with pixs of ocilloscope tracings to emphasize the point. Being an Electrical Engineer, i definitely appreciate the schematic diagrams of the different systems, the how it functions explanation of the circuitry and the evolution of the designs.
It will interesting to see if good old Nacho-RT74, copies any of the wording as his own work, omits half of the information, and paraphrases the rest.
I guess I'll just keep on wondering, just how the Pertronix device can do what's claimed in a small package....one of life's great mysteries...... And THANK YOU again for the link...it is very much appreciated.
Cheers......BOB RENTON