MSD Question....
 

Hey guys... Its time for hotter...sharper spark.... I am looking to upgrade my ignition to a MDS or Malory set up...

From what I understand I will need two boxes...two coils...

Can someone who has installed a setup give me an idea of how its done... Wiring...exc...

Thanks -

Here you go

https://www.rx7club.com/attachment.p...1&d=1197245556

Which is better.... One MDS Box or two?

This is going in my racecar...

Two. Even distribution of the spark to both coils.

It's a rotary, you only need one box for the leading. Trailing is a waste of money.

I learn something new everyday. Thanks for the clarification. :icon_tup:

+1 for what the troch says, i upgraded to a single MSD box about two years ago and have had excellent results

3 msds
 

Im really new to the rotaries but in sbc v8s it is rare to see more than one msd. I have seen RX7s with 3 MSDs what the point,does it make it spark more?

the little quote ive hurd was, 1 box gets you 90% of the way, the other 2 get the other 10%

So... Two boxes it is... 6A or 6AL?

doesnt matter. 6al has a rev limiting capability, the only difference. run one box through the leading with a 2nd gen leading coil and be done with it. simple install too!

Can you explain this a little more about the 2nd gen coil..... Thank you....

Use a 2nd gen leading coil with either the MSD 6a or 6al box....i perfer the 6al because of the rev limiter.

Woah, whats with wiring the leading and trailing coils in parallel in that diagram...Why would you want to do that?


The reason you see 2-3 MSD boxes is the guys who are using the rev limiter...cant be done with 1 box.
The guys who run 3 are either tired of replacing the cap and rotor from the multiple sparks burning them out, or want to run complete directfire.

Trailing seems to need 2 boxes for some reason. Jeff or Addict can explain it better, (waste spark?). Also need 3 boxes to even have rev limit capacity, unless trailing is disabled and the power for the tach and fuel pump are switched to the leading side. Trailing is no where near 10% of the power, much less.

Keep it simple, 1 box, 2nd gen coil optional.

IIRC 2 boxes can be used for rev limiting, trailing just has to be run through the cap..

People who run 3 boxes usually have a CAS and run direct fire (4 coils), Im not sure how or if you could run 3 boxes with a distributor.



Anyways, that aside...Am I the only one who thinks that first MSD diagram is a bit fishy??...
Seems to me the person who made that diagram has no idea about rotary ignition, or the flame propagation of the rotary engine...
Looks to me like that setup completely ruins the theory of leading and trailing ignition.

Yeah, shouldn't that wye to each coil instead?

I agree. 1 MSD + 2nd gen coil on leading. Trailing does so little, it is kind of pointless to use another MSD on trailing. Technically, you would need a pair of 6ALs for the rev limiter (running trailing through the cap). However, based on others experience, you can get away with just the 6AL on leading. Once the leading cuts out, you'll have a big drop in power which will help keep from over-revving.

On that diagram, the 1st setup will give 0 split timing. Whether this is good or not is debatable. I know that some, if not all, of the Mazda factory race cars ran 0 split. Other racers also run 0 split. For the street, it is best to leave the split in place, though (IMO).

Yeah, you don't need the trailing ignition. Only reason they're there is bored engineers wanting to entertain themselves and of course the accountants didn't complain... more spark plugs/wires for you to buy!

God I forgot how hilarious the first gen section was. Back to ignoring it.

False, you, in theory, dont even need to run a trailing plug with MSD. I run a MSD 6AL through the leading 2nd gen coil with no trailing ignition. Simple. Nothing running through the dizzy cap. It runs just as smooth as with the trailing in, no notice between the two actually...

Contact MSD and tell them that. They were the ones who gave me that diagram. I just give what I'm given. I went to them after I did my own searching on how to wire up an MSD ignition on my car (haven't done so, expensive, but I have 2nd Gen coil) and then I called them up to see what the deal was, since I didn't really find it on their website.

So is it ok to wire the MSD box like the first illustration suggests? Or is it a safe bet to wire it directly to the trailing coil? Also I remember seeing a tutorial on another site about wiring through the dizzy. How do you guys have your MSD box installed in your cars?

This is the way I have always done it:

One box.
Remove igniter from leading side of dizzy
Trigger the msd with the wires inside the dizzy that went to the igniter.
Black and orange wires to Leading coil #1
Jumpers from positive and negative of Leading coil #1 to Leading coil #2
Plug wires from Leading coils to Leading plugs

Ignition voltage to positive side of the trailing coil
Wire from top of "T" trailing igniter to the trailing coil negative
Wire from bottom of "T" trailing igniter to the trailing coil positive
Move trailing plug wires to leading side of dizzy cap.


Never had a problem and 6al limiter works

-billy

OK I am just a little confused. Should the jumper wires from positive and negative of Leading coil go to Trailing coil? Or do the Leading coil have 2 coils? I hope somebody makes a tutorial for this because I really want to learn how to install a MSD box in my FB before next autox season.

is it posible to run 2gcdfis with a msd? and if so you should really do a write up on it.

Damn... what happened to making this simple!

I will make it simple:

One MSD 6A/AL
1. To replace the stock leading igniter - no direct fire.

2. Direct Fire using 2 leading coils (aftermarket or stock coils). Strong and consistent spark.

3. Direct Fire using a FC leading coil. Spark is not as good as option 2. You have to remove/disconnect the FC igniter wires. If not, the MSD box will short out.

Thank you wackyracer for simplifying things for me. Now I know what to do now.

yw

I don't know if its too much to ask but, could someone who knows what they are doing (possibly waits or wackyracer ) post a diagram of the way they set their MSD up. A picture would really help.

also for the rotary which wires do you cut in the MSD?

whatever to make it run like a 4 cyl. I think it is all of them iirc.

Starting with the MSD box
MSD green wire to dizzy's red wire
MSD purple wire to dizzy's green wire

MSD thin orange wire to leading coil 1 positive
MSD thin black wire to leading coil 1 negative
*** Plus 2 short pieces of wires as jumpers from leading coil 1 to leading coil 2 and you do the same for negative.

****For FC direct fire, just connect the wires to the coil: orange to + and black to -. Again, be sure to disconnect the FC igniter as it will burn the MSD box.

MSD thin red wire to ignition wire. This is the MSD's on and off switch. Can be tapped to the black/wire wire that was originally connected to the leading coil's + termnal OR connect this to the trailing coil's + terminal. Either one will work.


MSD thick black wire to ground
MSD thick red wire to battery (be sure to add an in line 30amp fuse) OR to the FC fuse block for those who have done the upgrade.

Also, you need to set the MSD's cylinder setting. For rotaries, you want to set it for 4 cylnder - refer to MSD manual.


Be sure not to install the MSD box upside down. If not, just in case, water will get trapped inside and ruin your day.


areas where you can mount the box
http://img.photobucket.com/albums/v3...r/DSC04399.jpg
http://img.photobucket.com/albums/v3...Picture189.jpg

http://img.photobucket.com/albums/v3...r/DSC05728.jpg

for a visual

thanks alot guys. Now its going to be really easy to put my msd in.

OK-I've got this, but I'm eventually going to run an MSD with a S4 Crank Angle Sensor and a Haltech. Problem is I don't have the Haltech yet, but I do have the MSD,CAS, and an FC leading coil. At least one of you knowledgeable guys has got to know which system will produce a hotter, more consistent spark. If swapping the CAS in with the FC leading coil would be a better system, what wires from the CAS would I use to trigger the FC coil (and would I have to remove the ignitors from it as well)? I know you guys have answered similar questions many of times, so if there is a link that will answer my question I would be thrilled if somebody could direct me to it. Thanks for all your help guys!

-Adam Collins

Oh yea-I'm not worried about running the trailing plugs. I'll eventually find or build two "plugs" (solid threaded plugs to block-off the spark plug holes) so I don't have exposed spark plugs sticking out of the side of my engine block. I know I don't need to do this, but I'd feel better looking at my engine without the ugly tip of an exposed spark plug protruding from the side. It will look nice enough for me to care about that one day soon...

-Adam

Problem is that you cannot run the CAS directly to the FC coil (even with MSD in between). The CAS has no kind of advance (mechanical or vac). All it does is has two sets of teeth. One set to tell e-shaft position, the other to sync the trailing. You need an ECU (2nd gen, Haltech, ect.) to interface between the CAS and the FC coil w/ or w/o the MSD.

OK-that would be good with boost, right? I'm running it N/A until my project engine is built so even if it could be wired to operate it would hender my performance, not help. I'll clean the CAS and put it on the shelf until the day I install the Haltech...Thanks!

-Adam

ok i guess i still don't get it. I understand the wiring it just seems to me like having the two leading coils wired together is going to make the leading plugs fire at the same time? Aren't they supposed to fire at different times?

just wire it up and spark away. if this shit is bad, then my motors would have gone kaboom years ago. :)

this is true, i called msd and they said to do exactly what you said because the leading coils fire at the same time. Im just gunna call it magic because as long as it works that all that really matters. Thanks again.

ive been wondering about this for some time will this msd 2 tower coil for GM work as a direct fire coil?(option #2)

[URL="http://store.summitracing.com/partdetail.asp?autofilter=1&part=MSD%2D8224&N=700+ 4294925143+400122+4294839065+4294890813+115&autovi ew=sku"]

I run an MSD 6AL through a 2nd gen coil with no trailing. I love it. I choose the rev limiter pill and I am set. Great for autocrossing, never have to look down.

Several years ago Paul Yaw did some testing with and without the trailing and found that there was almost not affect to horse power, although the trailing really helped a great deal with emission.

So, if you are not getting emission tested at the track, forget the trailing ignition.

I have also looked at the MSD dual fire GM coil myself (the MSD version of a 2nd gen coil), but what I have works so well I just have not gotten to it.

So it will work right?

YES..will work just like 2nd gen. coil

im gonna be doing a swap to an MSD 6AL and 2 blaster 2 coils, eliminating trailing altogether. the only thing im worried about is the fuel pump. ive read in several places that the fuel pump is run off the trailing ignition. if so, what wire needs to be relocated to which terminal on the leading coils. ive got an 84 GSL-SE. ive searched around and havent found a definate answer, so i figured id post here.

Wow, lots of ways to skin this cat! To make this more confusing - here is what we are doing with the race cars in Kansas City. Pretty much what Billy describes above except that we are leaving the trailing side stock - using the ignitor, a single stock coil, trailing plugs fired from the distributor cap, etc.

On the leading side we also pulling off the ignitor and using the black/orange wires to the MSD 6A. In our installations we are using the MSD to drive a dual pole motorcycle coil. The coil is connected directly to the plugs - this is the wasted spark method.

Charlie Clark at KCRaceware.com found the coils - I believe they were originally for a 6V application. They last about 2-3 seasons....eventually they get hot and fail or the epoxy case splits. Yeah, we are over-driving the coil. I am now looking at several Harley Davidson 12V applications.

A couple of us have the leading and trailing ignitions wired separately so that we can easliy spot an issue by alternately switching each on or off. The engine changes pitch when you run only one side of the ignition and believe it or not you can do about 80MPH on the trailing only side.....