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I was looking on ebay for a new ignition coil and came across these MSD6al CDI Ignition Unit

Below 3,000 rpm, the 6al Ignitions produce a series of sparks that last for 20° of crankshaft rotation. This series of sparks will smooth the idle, produce quick starts and deliver lightning quick throttle response.

The 6al will work on most engines equipped with a distributor and is supplied with detailed instructions and wiring

OPERATING SPECIFICATIONS
Operating Voltage: +10-18 VDC Negative Ground
Current Requirements: 5 Amps-5,000 RPM
10 Amps-10,000 RPM
RPM Range: 14,000 RPM with 14.4 Volts
Spark Duration: 20° Crankshaft Rotation
Energy Output Max: 105-115 mJ Per Spark
Weight and Size: 2.75lbs., 8"L x 3.5"W x 2.25"H
Voltage Output Max: Primary: 460-480 Volts
Secondary: 45,000 Volts (Blaster Coil)

From what ive read, it delivers up to 14 sparks per revolution at idle and this number decreases as revs increase

Was searching for something else when i spotted this now older thread. I run one of these MSD6AL systems in my V8toranasaurus. The spark discharge was greatly improved using the 6AL (must use the blaster coil too) which improved economy, starting, and overall power. Didnt really feel it improved throttle response as it has great pick up already.
If you use one with a points dizzy you will never have to change a set of points again as they become just a low voltage trigger for the discharger.
They also come with several preset rev limiting 'chips' (you choose what rpm, ie 7000, 7500, 8000etc) which drop the spark to a cylinder on every second revolution past the designated chip value, that way it doesnt fuel up the plugs as it ignites it the next time around.
Mine is also hooked up to the MSD programmable timing computer which you can make your own timing curve with and even has a high speed retard (not me personally, im no window licker) which is good for extra power and also saving the old v8 from catastophic failure!!
I have heard now there are some equal, poss' better, digital units on the market like the Crane fireball CDI system, but i dont think they are compatable with an EJ25 in a Brumby so i dont care!!!
Hope this helps someone!!!

Been looking into this subject quite a bit of late. I am going down the "as money dictates" road meaning the first purchase will be the coil then the MSD box.

I think you should do some searches first on capacitor discharge ignition systems because they are not without their disadvantages . Personally I think a transistorised ignition system is easier and a bit less bitey .

Where CDI does work well is in dinosaur V8's with huge combustion chambers and poor air fuel mixture distribution from carburettors on manifolds with lots of variation in inlet tract lengths .

MSD 6A/AL's sometimes have a bad habit of failing for no very god reasaon , though the higher voltages involved would have a lot to do with this .
Virtually ALL manufacturers use transistorised ignition systems nowdays and they wouldn't if there was a cheaper easier way to light ultra lean mixtures .

Cheers A .

discopotato03 wrote:.....huge combustion chambers and poor air fuel mixture distribution from carburettors on manifolds with lots of variation in inlet tract lengths .


Cheers A .

drop the v8 term and me thinks it describes ea82t quite well:p
probably why a CDI type ignition works so well on them.

subject has been discussed b4,see
showthread.php?t=5295&highlight=Capacitor+Discharge
showthread.php?t=4493&highlight=Ignition

do note that the electronic distributor being used as trigger, the signal does not behave in its dwell time like a mechanical points dizy does,
so would be interesting to know how well the MSD triggers from it, I do believe they have a micro in them for smart triggering so might be fine.

Main reason i am more than just thinking about it is, when the engine is being boosted high i keep blowing the fire out i have tried reducing the gap of plugs and also tried an assortment of readly available coils to prevent it so now im on the track of aftermarket ignition.

that is exactly what it helps with, I wasn't boosting higher, but was using water injection, under boost, the standard coil setup is just not enough, CDI fixed that problem really well.
And with the multiple sparks, it idled so smoothly;)

fredsub wrote:drop the v8 term and me thinks it describes ea82t quite well:p
probably why a CDI type ignition works so well on them.

subject has been discussed b4,see
showthread.php?t=5295&highlight=Capacitor+Discharge
showthread.php?t=4493&highlight=Ignition

do note that the electronic distributor being used as trigger, the signal does not behave in its dwell time like a mechanical points dizy does,
so would be interesting to know how well the MSD triggers from it, I do believe they have a micro in them for smart triggering so might be fine.

they have a tach adapter for those - in plain form it will not fire as the unit needs to see an earth to fire the main coil. (mine didnt anyway.)