Thread: MSD ignition system?

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I’ve pondered upgrading my ignition system with a MSD box for awhile. Having the Pertronix electronic point conversion and high output coil already, I wondered how much of a difference the MSD could actually make?

I researched both sides, reading posts of both the Pro’s and Con’s and I gotta tell ya the fence is divided.

Con’s; say a good tune-up will do more for performance than the ignition box. Adding that the boxes give trouble, are hard to install and most times don’t work correctly.
Pro’s; say MSD is easy to install, just follow the directions and expect a big difference on performance and milage.

After talking to several people in my car club that I know have the knowledge on the subject, I decided to take the leap and order the MSD Street Fire ignition box along with a matching distributor cap and rotor (as recommended by MSD).

Installation was easy, only took me about two hours. Probably could have done it faster, but I am incredibly anal about things. I mounted the box under the dash near where my coil is and ran the wires as instructed. I did not change anything other than the distributor cap and rotor, leaving the old plugs in place and only re-gapping them as recommended by MSD. I did this deliberately as some (con’s) had said new plugs were probably the real reason for increased performance (and they’d be wrong). Also ensuring I had a good ground and power source directly from the battery for the MSD. As a knowledgeable mechanic friend pointed out to me, the power and ground source from the battery is imperative and when not sourced correctly is the reason so many have trouble. Thanks Tom!

I set the rev limit, hooked the battery back up and lit it off. Instant start, idle sounds better, smoother and deeper, more powerful (I know that sounds funny). Out on the road, the throttle response is quicker and peppier, there’s no lag or bog of any kind, even when I dump both fours! WOW! I’m pretty excited! And, the motor is smoother at cruise speeds too! With pickup and passing all improved dramatically as well, it even runs better when cold. Much more fun to drive!

Milage, well I can’t tell you that yet, as I haven’t taken my foot out of it long enough to be able to check! LOL!

In summary, if you’re thinking about adding an MSD ignition box, DO IT!

Follow the instructions, be sure you source the power and ground for the MSD from the battery and you will be rewarded with big performance gains for the buck!

MSD----------multiple spark distributor----------simple enough-----------

They really do help the firing at low rpm's with the multiple spark. I've had my share of problems with the boxes, but never had any problems getting MSD to stand behind them, either! Using the 6 Digital now, so much versatility on what you can make the box do for the engine!!!

Question from the Peanut Gallery - - - - I have an HEI Dist on my 289 Ford that works great but I was just wondering if the "Box" could ever be added or do they use a different Dist???

MSD instructions shows a hook up diagram for HEI and the Street Fire box.
http://www.msdperformance.com/Produc..._Ignition.aspx

Hooking this up was a night and day difference in performance!

i have always ran way too big of cams and way too much carb on my hotrods .. had to change out fouled plugs every month with stock ignition .. switched to MSD 10 years ago and have never fouled a plug since ..it`s my understanding it will fire a plug on every exhaust stroke under 3000 rpm ..they did have some problem with clone boxes which i think has been discussed on here ...

I've got a 6AL on my 46 and a 6 Digital on my T. I'm running their distributors, also. Both work great. The one on the 46 has been on the car for about 15 years.

The only thing I have noticed is that the plugs seem to "wear" a little faster. Might be because they fire 3 times more often than a stock ignition below 3000 RPM.

Mike

Are the plugs gaped wider?

Yes, I have mine gapped at 45 thousands.

Thank you, I'm thinking about one for my 76 Vette

Originally Posted by 36 sedan

Yes, I have mine gapped at 45 thousands.

Same here.

Have MSD 6A, plug gap is .050, 10.5 comp. That is spec. range goes too .060 any thoughts on the .050 ?

i have used many msd setups. i never seen the need to open up the plug gap past .035 i never seen the need to test out my plug wires with to big of a gap

Pat,
I was under the impression that the wider gap allowed better combustion with the higher voltage? Is this thought incorrect?

bigger gap is not needed with a msd. or should i say... i never seen any gain with hi or low cr engines i gap at .035 with a hi cr it takes more volts to fire a plug so adding to that with a bigger gap plug adds more load to the plug wires and coil . thats the way i see it. i have seen guy with stock hei open up the gap by .005 to 010 saying the gap helps with time /build up hirer coil discarge = more volts to plugs = better burn ? just adds to coil break down or stray voltage finding a new home..a short path... .seen alot of this on the warranty side of boat engines repair