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Unread 10-18-2013, 05:56 PM   #16
86cj74.2L
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Quote:
Originally Posted by Dngrs1
Please trim those tie-wraps. They're driving me nuts
Old picture. It's been done a while.

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Unread 11-06-2013, 06:55 PM   #17
Cashcrazy
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I am up and running with the CDI. Idles better and the detonation is better. What is your plug gap running a CDI box. Mine are at .045 now and I didn't know if I should open them up a little more.
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Unread 11-06-2013, 08:40 PM   #18
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Which one did you get?
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Unread 11-06-2013, 08:55 PM   #19
Cashcrazy
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I ended up finding a deal on a Streetfire. It was purchased by someone, but never installed. I was real hesitant at first, but for the price I thought I'd give it a try. It's surely throwing a lot more spark than the old Chinese Duraspark I was running. It does say Made in USA right on the box.

I am trying to get my new electric choke adjusted and then I think its time to get serious about working out my timing curve.
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Unread 11-07-2013, 10:50 AM   #20
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Originally Posted by Cashcrazy View Post
I would like to install a CDI style ignition box, but am not sure which one to go with. The three I am looking at are MSD 6a, MSD streetfire, or the Summit ignition box. I am running a stock 258 with a MC2100.
GOOD!
You have been reading and know the CDI is a type of ignition module, not a brand name! GOOD START!

The last 'Summit' basic CDI module I took apart was more or less the original MSD 6 series box design. The patent finally expired, and EVERYONE made one of them since they have lasted so many years and are still the best alternative for common single coil/distributor type ignitions.

The only thing that bothered me was virtually all the parts inside had CHINESE WRITING on them...
I don't trust 'China' anything, and for good reason... EXPERIENCE!

Quote:
The MSD Streetfire is priced the lowest and of course I like that. I have read that the Streetfire is a 5-series MSD box and a big step down from the MSD 6-series. Does anyone know if this is the case?
MSD 'Street Fire' series is an attempt by the conglomerate that purchased MSD to introduce a 'China' product under the MSD name.
I don't care for the 'Street Fire' modules, I don't care for the 'Street Fire' plug wires... They aren't the usual MSD American Made product quality.

You also want to stay away from 'Off Road' modules or 'Marine' modules.
They are 'Potted' with epoxy and can't be repaired.
The 'Potting', or water proofing, also traps heat and I've not had very good luck with them at all.

Quote:
I have read the Summit box is made by MSD with MSD internals. Just looking at the specs it appears to be a digital version of the 6al. I am sure this would work just fine if is made by MSD.
Not that I know of, but I haven't had one apart from Summit in the past couple of years. The 'Summit' brands were made in China or Taiwan last time I looked.

They are virtually an exact copy of the original MSD 6 series modules, with the exception of a little more modern versions of solid state switching.

------------------

---Just a geek fact,
In this application, 'Digital' refers to the switching signal.
Some switch signals taper 'On' and taper 'Off', where 'Digital' refers to a very clean circuit connection or break, an almost vertical line instead of the old taper up and down for 'On' & 'Off'...

The 'Base' CDI modules, best for our applications since we have vacuum advances, centrifugal advances, ect. are just 'On' & 'Off' so 'Digital' doesn't apply to us, we don't let the module control the advance/retard of the timing signal...

It's a small, but critical distinction.
The faster the switching to the coil, which the base model is more than capable of handling fine, is great for what we are doing. Technically, it's not 'Digital' since it's not handling information (like timing advance applications would) it's not 'Digital'...
--------------

Quote:
The MSD 6a box would be my safe purchase option if people chime in with poor feedback on the other two options. I may can find a used one online and save some money, but there is always the risk of it being burnt up and then no refund.
It's been a couple of years since I sent one in for warranty work, but MSD used to fix and return your MSD 6 brand module for free, no matter if you weren't the original purchaser or not, and no matter how old it was.
I can't attest to that now since I so rarely have to send one in... And since the conglomerate that purchased MSD has been cutting corners.

Quote:
I appreciated any feedback if you have tried any of these boxes.
The advanced 5 series MSD module would probably be fine for our Jeeps.

I use MSD 6 series because they were laying around here, and because they were the most bang for the buck until MSD sold and the price went from $130 to around $200 or more, while the 'Knock Offs' (of varying quality) started coming out at under $100, but the were disposable, no warranty after about 90-180 days...

Jacobs was the worst of the CDI modules, until Jacobs sold and they started using the old MSD design, then they became pretty reliable.
Summit had a $90 knock-off of MSD 6 series that was pretty good, but the price went up when they started calling it 'Digital'...
MSD 6 series has gone up over double, to about $250 in a lot of places, but it's still reliable, just not as good of a deal as it was.

No doubt, CDI is the best way to drive the coil for MAXIMUM spark energy output, but you have a choice between makers. About all the basic designs are the same old MSD designs, with the exception of updated switching transistors, ect, so it's up to you...
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Unread 11-07-2013, 10:53 AM   #21
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Originally Posted by Dngrs1 View Post
Please trim those tie-wraps. They're driving me nuts
I hate working on anything with trimmed zip tie ends. They always get cut off with a sharp point that scratches the heck out of me!
I leave the cutting until everything is in and bundled/covered.
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Unread 11-07-2013, 11:20 AM   #22
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Originally Posted by Cashcrazy View Post
I am up and running with the CDI. Idles better and the detonation is better. What is your plug gap running a CDI box. Mine are at .045 now and I didn't know if I should open them up a little more.
You are at about the top of the plug gap you want to run.
Around 0.045" you are driving coil voltage up about 45,000 volts, which is plenty to fire any fuel I can think of.

If you open the plug gap up more, you will be converting more of the spark energy to Voltage to jump that larger plug gap...
And making any more voltage will subtract from Amperage (Heat in the spark) and from Duration (Time spark lingers in gap).

That's why I say 'Spark Energy' and not 'Voltage' that all the 'Clone' ignition assemblers rant and rave about...
(I know the electrical principals, not just how to assemble parts)

Closer the plug gap, the lower Voltage it takes to jump it.
Back when we were stuck with breaker point ignitions, there were plug gaps at 0.025". That was because breaker points don't open and close 'Cleanly'...

They arc over, that makes a 'Taper' to the open/close cycles.
You want the power to come 'ON' full bore, no taper.
The quicker it makes full power reach the ignition primary winding, the LONGER (Time) the coil primary windings get to build a STRONG magnetic field around the secondary windings.

You want the primary circuit to break clean (OFF!), not taper down.
When the circuit tapers, the voltage reduces (Relatively) slowly reducing the magnetic field in the primary windings, that reduces the intensity of the magnetic field that will produce the secondary (High Voltage) discharge.

The 'Cleaner' and faster the primary circuit closes the more TIME you get for full power building of the Primary magnetic field.

The 'Cleaner' and Faster the primary circuit OPENS, the longer you can let the magnetic field build, and when disconnected,
The more intense magnetic field will collapse through the secondary windings and the more intense secondary discharge will result.

It's not just current through the coil, but how FAST you can switch.
The faster you can switch, the longer you can build magnetic field can build for a good output when you break that current flow cleanly.

Transistor switching is VERY quick. It was so much faster in early electronic ignitions output spark voltage from the same coils went from around 8,000 to 18,000 volts, to around 25,000 overnight as the 'Breakerless' ignition modules came into production,

And as upgraded, faster switching came about, to about 35,000 to 45,000 volts.
Now, when you see some 'Clone' company advertising '50,000 VOLTS!" or '60,000 VOLTS!'...

From what is basically a stock ignition coil you have to ask yourself,
"AT WHAT COST?"

They aren't getting any more time to build magnetic field, the engine is still limiting time between discharges, crank speed sees to that...

They aren't putting any more windings into the coil, size restrictions from HEI caps and coil brackets see to that...

The little secret they won't tell you is... (Drum Roll...)
EVERY FACTORY COIL IS CAPABLE OF 100,000 volts or more, just open the spark gap...
(Ever see a 'Leaking' HEI coil discharger AROUND the cap to the distributor base? That's 4" or more)

The higher you drive voltage by opening up plug gap, the more of the magnetic field has to be converted to Voltage to jump the gap,
Conversely, the LESS magnetic field collapse through the secondary windings there is to create Amperage and Duration.

If you look at those 'Super Duper 50,000 VOLTS!' coils, they recommend a 0.050" or 0.060" plug gap. That's WAY TOO MUCH and it robs you of Amperage & Duration at the plug gap.

Also, since there isn't any more room in the coil for INSULATION,
You can EASILY drive voltage up so far it jumps THROUGH the insulation INSIDE THE COIL BETWEEN WINDINGS...
This Damages The Coil! You won't see it, but it's damaged every time the ignition fires and eventually will quit working...

Keep the voltage reasonable, around 35,000-45,000 volts, and the coil can handle it, plus you build some good Amperage and Duration.

The big trend was to make the plug gap larger, but in racing engines on the dyno we found out there was a limit of around 0.045" where you simply didn't see any rewards, and reliability started to suffer... We are talking gasoline engines and propane/CNG engines here, not exotic fuels...

Now, start to consider WHY YOU DID THE LARGER/TALLER CAP UPGRADE WITH GOOD PLUG WIRES...
You wanted to CONTROL THE SPARK ENERGY THE STOCK IGNITION WAS PRODUCING...
Often times, this is enough spark energy to keep the average engine running happily...

When you drive the spark voltages WAY UP, you are back in the same boat.
The spark is jumping around, looking to burn it's way out to 'Ground' before it reaches the plugs...
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Unread 11-07-2013, 11:43 AM   #23
EgulAye
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I hate working on anything with trimmed zip tie ends. They always get cut off with a sharp point that scratches the heck out of me!
I leave the cutting until everything is in and bundled/covered.
I'm right there with you Aaron. When I'm done I'll trim each one carefully with a razor knife and double check to be sure I cut it flush and smooth. If I can't reach to cut it clean then it keeps the "flag" in perpetuity. I'm done with the scraped hands and knuckles - no more bleeders.
,Dave
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Unread 11-07-2013, 11:53 AM   #24
JeepHammer
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That's why CDI works so well...

CDI saturates the ignition coil with 400 to 500 volts (DC) and that builds a magnetic field VERY QUICKLY AND VERY STRONG compared to the 8 to 14 volts the factory ignition delivers to the ignition coil.

Electronic modules gave you CLEAN SWITCHING, much better than the ramp up/down that breaker points produce,
So much cleaner that the 'Saturation' (Magnetic Saturation Time) the coil 'Sees' (Time) was increased,
So the same type of coil could discharge with DOUBLE the spark energy as a breaker point ignition would build.

You are still limited by a SINGLE EVENT in the coil. Magnetic Saturation, Circuit Opens, Magnetic field collapses THROUGH secondary windings INDUCING a secondary current.

That secondary current event (Time) is limited to how long the magnetic field takes to collapse though the secondary winding...
Once that magnetic field collapses through the secondary winding, you don't get anymore current production, so the spark event stops.

With 'MSD' (Generic 'Multipul Spark Discharge, not the name brand), you get that coil to saturate VERY QUICKLY, it discharges at the spark plug (*IF* everyting else delivers the energy to the plug gap), and you have plenty of time for another 'Spark' at lower engine RPM.

Now, if that first spark didn't get the fire lit, or didn't get it lit PROPERLY, the cylinder either misfires, or it produces a lot less combustion force than it should have...

So MSD came along, and what they did was deliver several sparks at low RPM when there is TIME for several sparks (Slow crankshaft speeds, low RPM).

MSD can Magnetically Saturate and discharge the ignition coil about 5 or 6 times in a row before that time 'Window' passes as the crank turns...
These are FULL POWER, FULL DURATION SPARKS WITH PLENTY OF AMPERAGE, in what is otherwise wasted time and into what was otherwise wasted combustion mix... You get 5 or 6 bites at the apple, chances to get that cylinder lit!

Now, the time DECREASES as Crankshaft Speed Increases...
With a single fire 'Factory' electronic ignition, the length of the single spark is about equal to time the crankshaft is in position for optimum spark timing at about 1,800 RPM.

After 1,800 RPM, the coil doesn't have time to fully saturate, therefore the spark energy output goes down with increased RPM.
By about 2,500 RPM, the spark is VERY weak, the saturation times in the coil have been cut to the point where it's barely functioning, and spark voltage stays up since the coil builds voltage FIRST, then delivers amperage and duration after the arc starts in the plug gap... It's the Amperage and Duration that suffer...

By around 3,500 RPM, the voltage starts to suffer since saturation times are cut so short, and you have virtually no Amperage or Duration.

With CDI, you get SEVERAL sparks up to about 2,500 RPM, keeping that spark alive and viable to get the fuel mixture lit,
And beyond 2,500 RPM most CDI modules start with a SINGLE spark, but that spark is VERY HIGH POWER since you are saturating the coil with 400 to 600 volts!
You get a single spark, since you don't have time for more, but that spark is LONG DURATION AND HIGH AMPERAGE.

That's why a CDI module will fire up to about 15,000 RPM RELIABLY, where most 'Factory' type ignitions fail somewhere between 5,000 RPM and 7,500 RPM.

Now, we don't run 15,000 RPM engines! We don't even run 7,500 RPM engines.
If we see 5,000 RPM very often is highly unusual...

*IF* you are running cast iron factory rods, you are taking your engine's life into your right foot if you get past about 4,500 RPM...
I'm just saying...

But it's the LOW SPEED operation we are most concerned with.
A well tuned factory style ignition will RELIABLY fire an over rich carb engine at 4,500 RPM, but more importantly, it will fire a low speed engine fairly reliable. Down in the RPM range where you wheel and drive on the street.

A CDI module will help get the fire lit at the CORRECT TIME when things aren't so 'Well Tuned'...
Damp days, excessive under hood heat, bad fuel, times when the fuel mix is too rich or too lean, when there are things like carbon/oil or exhaust fumes left in the cylinder...
It will help you squeeze out some extra fuel mileage and/or power when you need it, and under less than 'Optimum' conditions.

That's why some many people see emissions decreases with CDI, and that's why so many people see faster starts and better 'Cold Running' until the engine heats up.

Anyone with a well tuned factory ignition can get it to fire almost every time, but what happens when those new 'Tune Up' parts aren't so 'New' anymore?
We've all had those 'Issues' or the ignition fixes and upgrades wouldn't be so prevalent...
The hard starting, the dying, the 'Chugging' until it warms up, those are all signs of something NOT being in 'Tune'...
Carb issues, choke issues, fuel metering issues, ignition problems, valve guides leaking, worn rings leaking, camshafts that have worn and not delivering proper amounts of fuel/air to the cylinder and not removing the exhaust from the last cycle, plugged up or too small air cleaners, we all have these issues the SECOND time we start a brand new everything since everything wears as it works...

Throwing a little more spark into that cylinder will help overcome some of these issues... And more...
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Unread 11-07-2013, 11:58 AM   #25
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I'm not a real fan of Zip Ties. They have their place, but I'd rather use something I can remove and doesn't remove my skin.
People that don't do a lot of tight space work won't get this, but a 5" long deep scratch is VERY distracting when you are working.
Hurts worse than an outright cut since all the nerve endings are still intact and screaming PAIN!

I use a cheap version of those plastic reusable hose clamps now.
I can feed more wires though them without having to cut and rebundle with zip ties,
They are removable when I put shielding on the wiring,
And they are color coded so I can keep my bundles straight when I'm wiring.



They are DIRT CHEAP so if you loose them, big deal...
These are too flimsy for hose clamp duty, but for bundling wiring or keeping wiring up out of the way, they are great.

I HATE working on a harness that has been TAPED UP! Drives me nuts trying to trace a wire.
And zip ties aren't much better...
I still string tie my harnesses since I never know what changes I'm going to make... String leaves enough slack to pull or insert another wire, and string never gets in the way of split loom shielding like zip ties do.
Now, Zip Ties on the OUTSIDE of the split shielding are a good thing! The guys that tape up the harness, then tape up the split shielding get charged DOUBLE since I have to strip tape TWICE!
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Unread 11-07-2013, 12:17 PM   #26
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There are tools made specifically for cutting zip ties that don't leave a sharp barb like when you cut them with side cutters/wire cutters.
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Unread 11-07-2013, 12:42 PM   #27
JeepHammer
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Just what I need, another 'Specialty' tool just for zip ties...
Like I don't have enough of those for the 200 or so connector types, for stripping, crimping, sizing, labeling, terminal tools, ect.

One thing about leaving the tails on COLOR CODED zip ties, it makes it easier to trace certain circuits once they are in the split loom, since the tail sticks out...
Not really a big deal with Jeeps, but good for other applications.
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Unread 11-07-2013, 01:04 PM   #28
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Ho la la !!!
My english isn't so good to understand at the first time, I need to read it again.
But 2 questions :
- I found out two MSD 6A, 6201 it's the new one and the 6200, are there the same unit ?
- the 6200 is it the old one made in USA ?
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Unread 11-07-2013, 02:42 PM   #29
JeepHammer
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Originally Posted by steff View Post
Ho la la !!!
My english isn't so good to understand at the first time, I need to read it again.
But 2 questions :
- I found out two MSD 6A, 6201 it's the new one and the 6200, are there the same unit ?
- the 6200 is it the old one made in USA ?
6200 is the common, no extras MSD 6A, perfect for Jeeps.
4-6-8 cylinder EVEN FIRE engines.

6246 is the one you want to stay away from unless you have an ODD FIRE V-6 engine. Big red flag on this one, waste of time and money unless you have a Dauntless V-6 Odd Fire engine.

6420 is the MSD 6AL. has a built in rev limiter. 4-6-8 even fire engines.

6201 was made with a very specific plug in feature that was for the 5.0 L. Ford Mustang harnesses.
Not exactly good for Jeepers since we don't have computer/fuel injection controllers.
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Unread 11-07-2013, 08:49 PM   #30
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Jeephammer - I appreciate the amount of time you put into your informative responses. I wish I could find a local Jeeper with your experience. I stubbled across a post of yours(not sure which forum) about timing advance curves and dialing in on them. One of your advance curve threads should be added to your signature. I feel like the advance curve is often over looked. I bet I referenced your ignition upgrade link 40 times.
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