Should I get rid of my msd 6a?

[Mtgrizzlymn]

It was on my bronco when I bought it, I really have no idea what it does. Is it more reliable to just get rid of it? Plus my tach don't work with it lol

 

[bronconut73]

MSD has a tach adapter you can get. It will give your tach a signal it likes.

The MSD (multiple spark discharge) 6A box provides multiple sparks per combustion event below 3000 rpm and a long duration single spark above 3000 rpm.
Translation, more complete combustion and theortically smoother idle.

It truly has its place but is best suited to a truly high performance engine with higher than typical compression. I ran one for nearly 30 years. Not running one now but I have a Pertronix distributor that does a little of what the MSD 6A does on its own.

 

[englewoodcowboy]

It truly has its place but is best suited to a truly high performance engine with higher than typical compression. I ran one for nearly 30 years. Not running one now but I have a Pertronix distributor that does a little of what the MSD 6A does on its own.

Completely agree. I would opt to have less is more simple system such as a petronix etc vs. deal with the MSD stuff unless you have a full on performance motor. I like the less is more theory when it comes to electronics on a bronco...

 

[pcf_mark]

MSD was originally developed to fire lean mixtures from the emission era it just works out that it helps fire any mixture. It is not a race part it just has a lot of racing marketing. If it is not giving you any problems it never will. Unless you jump start your truck wrong or you submerge it.

I have found Pertronix to be flaky and refuse to use them. I have used MSD reliably for 30 years. But they did have some cheap off shore copies that sucked.

 

[00gyrhed]

I thought MSD stood for My Spark Disappeared.

I have no experience though.

 

[dave67fd]

I had one with my Pertronix and it made little to no diffrence plus it randomly died about 2 years later.

 

[C Saporito]

If you already have it there is no investment involved, you're not going to get an improvement by purchasing something else.

 

[lowbush]

I like mine it allows me to run pump gas in my stroker yet keep the higher compression.

 

[Tiko433]

I'm running one ..... I added a SunPro tech Hooked it up to signal wire , no issues. The systems needs no adjust or maintenance

 

[Dlish]

MSD was originally developed to fire lean mixtures from the emission era it just works out that it helps fire any mixture. It is not a race part it just has a lot of racing marketing. If it is not giving you any problems it never will. Unless you jump start your truck wrong or you submerge it.

I have found Pertronix to be flaky and refuse to use them. I have used MSD reliably for 30 years. But they did have some cheap off shore copies that sucked.

Hey I resemble that remark!! Yes, I can vouch that the MSD boxes don't like being submerged. (2015 Bronco Roundup RIP one MSD box) BUT, it did work for about 2 hours after said water incident and get me back to the campground. It was the overnight stewing of water and fine electronics that disagreed with it most.

But otherwise, the MSD setup has been awesome. And mine has a tach wire that seems to work fine…does your tach not work at all?

How many doods does it take to diagnose a flooded MSD box? Many apparently.

 

[Mtgrizzlymn]

My tach will work on highway but when I stop it stays at 2000 or so then will start again when I' got the revs up!

 

[broncnaz]

Id keep it for now since its on there but I would make sure you know how to remove it and still have your bronco run as sooner or later it will probably fail. That may save you a long walk. Ive seen way to many MSD boxes fail for the relatively small number that are out there compared to stock setups. Same goes for pertronix lots of failures with them compared to stock setups.

 

[Bferrari]

The 6a box is one of the best out there in my opinion. It's been around for decades and work well and are very reliable. I would definitely keep it

 

[Dlish]

My tach will work on highway but when I stop it stays at 2000 or so then will start again when I' got the revs up!

What tach are you using? I believe for some tachs you can use the wire directly from the 6a box, and others you may need a tach adaptor that msd sells.

My tach is from one of the Bronco vendors (looks like the original speedo) and just uses the tach signal wire directly from the msd box. It is getting good power and ground?

 

[bronconut73]

I think the older MSD boxes have issues with some tachs.

I needed the MSD tach box for my old 6A and an Autogage tach.

 

[Mtgrizzlymn]

My tach is the one from the vendors that matches dash, very cool looking I think. Better when it will work lol.

 

[67RT]

Keep it! Woke up the 327 in my Vette. Great box.

 

[76Broncofromhell]

MSD's are complete garbage. They have a great marketing department is all. They are an improvement compared to points style ignition - which haven't been factory equipment since Nixon was president.

They are prone to failure because of how they actually work and completely unnecessary on a street rig. You will see little to no power delta between an MSD and other breakerless ignition systems. They were a way to get high RPM (+4500) before breakerless ignition modules could handle the amperage associated with short dwell times and higher resistance coils back in the 1970s. Today, a $20 GM HEI module that can be found at any parts store in the western hemisphere can support in excess of 6,000 RPM assuming you have a performance coil.

HEI Module EE information
http://cyberdave.org/HEICoilInfo.html

How to hide one in a Duraspark module. I've hidden them in old Ford external mechanical voltage regulators as well.

You can even hide the thing in a Ford case if it makes you feel better:

 

[patterdale]

MSD has a tach adapter you can get. It will give your tach a signal it likes.

The MSD (multiple spark discharge) 6A box provides multiple sparks per combustion event below 3000 rpm and a long duration single spark above 3000 rpm.
Translation, more complete combustion and theortically smoother idle.

It truly has its place but is best suited to a truly high performance engine with higher than typical compression. I ran one for nearly 30 years. Not running one now but I have a Pertronix distributor that does a little of what the MSD 6A does on its own.

I have question. Once the initial spark has ignited the air fuel mixture what on earth can another spark contribute? Or, a longer spark? Sounds more like a marketing gimmic than actual science or physics. To my knowledge once the ignition is started it is up to fuel type/quality/formulation from ignition point on. Please, someone with more knowledge enlighten us all.

 

[bronconut73]

Under higher than typical compression or the lean fuel mixture of the late 70's it does help.

The MSD box has its place but maybe not for us low rpm off roaders.
But I like what Broncofromhell is doing with the HEI modules. They are cheap so you can afford a spare. Heat usually is what would kill them and he has them out of the hot distributor and onto the much cooler fender hidden in a stock box.
Bitchin