Thread: Need an education on MDS ignitions.

Tweet

I have zero experience with MSD boxes, but am considering one. The ones I am talking about are the 6A, 7, etc models. What is their function? Do they replace a coil, or suppliment one, or what? How do they wire into the system? Are they worthwhile on a street driven hot rod?


Don

They have an excellent website, including a forum section that will give you more info than you can probably absorb: http://www.msdignition.com/forum/forumdisplay.php?f=5

I've had a couple, they work fine. In high performance demand (basically racing) they get the job done. MPO is they are pretty much overkill for a street putter, probably half of them out there are for the boy racer look and never get pressed for their full capability. One of the ones I had failed once and I sent it back for repair. The service dept was quick and reasonable. For a street driven rod I prefer a self contained, ready to run electronic ignition, functions well, and you don't have to find a spot for that big clunky red box.

Multiple Spark Discharge. It is actually a control module that is compatible with high energy coils.
It only needs a triggering device such as points, reluctor, or hall effect switch.
It does discharge a multi spark during a single firing so every time a cylinder gets lit, it actually throws a few pulses during that time.
It's big advantage along with higher voltage is the contolled duration.
V-8 firing of the MSD box is 20 degrees of crankshaft rotation.
Depending on your distributor, wires, plugs, and cap set up, there is a chance of ignition static in your radio. It does require a good, high quality ignition set up or it will use up or burn up the cheapy stuff.

Don, I've had a 6A on my 57 Olds for about 20 years and it has yet to miss a beat. I also upgraded my points distributor with a Pertronix Ignitor and a MSD coil. Whole system works well together and eliminates 99% of the ignition problems that I had before.

A lot of people that I have talked to prefer the 6AL over the 6A because it has the rev limiter. A little more money for extra protection.

I've run the mallory unilite and MSD 6AL (with their high voltage coil). The box contains power electronics to provide capacitor driven multiple sparks at low to medium rpms. At high rpms there is not time for several sparks so it functions more like a regular high voltage ignition in that realm.

I bought my first one in 1988ish for my '68 427 Vette when its factory transistorized ignition starting getting weak. When I put the MSD in I was sold forever. That Vette came alive down low like it had never done before. It really helps starting and warm-up. When the X wanted to drive it one day I slipped in the 3000 rpm rev limit pill. When she came back she said "something's wrong with the Vette". I said, "What do you mean; you weren't abusing her were you? "

Excellent product and customer support IMO.

Kitz

i used the 6al s in some builds has well as my stuff .nice stuff it works good . if you are looking to up grade from a Hei or points they work very good .but a stock reworked Hei for every day to mild works good to . a merc thunder bolt works very good to if you find one at the boat yard just laying around

One thing I didn't see mentioned is past a certain RPM the MSD boxes stop throwing a multiple spark and just make a single spark (seems like it's under 2000 RPM somewhere).

You also want to watch how you route your wiring that goes to the pickup, it can pick up some stray signaling from the plug/coil wires which makes a real interesting problem to track down.


".....MPO is they are pretty much overkill for a street putter, probably half of them out there are for the boy racer look and never get pressed for their full capability...."

I totally agree with Bob on this. That being said I'm running one on my Mustang II, the 351W with performer RPM heads (no heat crossover) was a huge pain on the mornings it got below 30 degrees here and the MSD made it drivable before it came up to operating temperature.

I'm also running a 6AL (rev limiter feature) on the 57 for peace of mind with the 4 speed and 4.10 POSI. WIth the cam tha's in that one it also helps the idle unitl it's fully warm. Once either car is fully up to temperature there is no seat of the pants difference detectable.

any thing i put a msd 6al in is not over kill

Thanks everyone for the replies. I never understood exactly where the MSD box went into the ignition setup. I thought maybe it replaced the coil, but it looks like you use everything you would normally use, and then add the MSD to get the benefits of multiple sparks at low speeds.

I agree that hiding that big red box would be an issue, and since we rarely get below 45 degrees here I won't have to worry about the cold start thing. I think I'll pass for now, and maybe just put one on the drag car I'm planning some day.

Don

i put the big red box inside the car on the fire wall and coil as well

Don, If you have to buy all new components, MSD might just be the way to go, but this is not a cheap set up when you can use a modified HEI system. I have the entire MSD arrangement on my car, from the small diameter billet distributor, the 6A box (I'm never going to need the 6AL for racing), the coil and for my VDO gauges, a special box for the tach. My wires are Taylor instead of the MSD as I believe they are the same and I needed a universal set which MSD didn't have at that time. How much do I have in this arrangement:

Distributor = $285
Steel Gear for roller cam = $50
6A Box = $175
Blaster 2 Coil= $45
Tach box = $60
Taylor Wires = $60
(some of these have gone {way} up in price lately)

This is how I "hid" the box:

Mine and the coil are under the dash behind the firewall. Real easy to disconnect for added theft protection too .............

Kitz