Ignition

scoutpappa

scoutpappa

Member
I recently purchased a 1979 Scout II. I own other scouts and drove one through high school. I picked the Scout up in idaho and proceeded to drive it a 1000 miles to where I am in wy. After a month the engine died cleanly on the way to work. The po had a pertronix module installed no ballast resistor and an accel super stock coil. After ohming out the coil I determined that it was time for a replacement. No fire at the plugs. At this time I chose to go with an ignition system I had experience with. I purchased a mallory unilite vaccum advance distributer (optical trigger). I kept the accel super stock coil, installed a ballast resistor 1.5-1.8 ohms. I changed the plug wires to a 8mm msd wire (universal kit). I have not changed the plugs. Drove fine for a few months and now I am back to no fire. The truck died and then restarted and died the final time a hundred yards down the street. I am from louisiana working n gillette wy currently. I have zero experience with setting carbs above sea level and no time so I had to get a local shop to install the distributer. The two differences in this set up vs my other Scout is the resistor and the accel coil. Should I buy a msd blaster coil and get rid of the resistor. Has anyone had issues with a mallory unilite failing this early. I have never left the key on for more than thirty seconds, only to start. Any help would be appreciated.
 
A mallory unilite distributor must use the ballast resistor supplied with the unit when new. No way around that. It's simply part of the unilite technology.

And...the distributor must be used with an ignition coil of the correct primary resistance factor. The oem coil used with all IH sv engines (no matter if breaker points, gold box electronic, or prestolite electronic) happens to be the perfect coil factor for the unilite.

But...the wiring for the unilite and the coil must be done in accordance with the instructions provided by mallory, the oem ignition feeds simply are not correct, start from scratch and wire according to mallory and it will work just fine!

The wiring used with breaker points on IH stuff is totally different from the gold box wiring which is totally different from the prestolite wiring, this is not a "they are all the same" situation!

The aftermarket coils are only slightly "hotter" than an oem coil from IH. Slightly higher turn ratio but same relative primary resistance value. One is just as good as the other as long as the primary resistance value is correct for the unilite distributor.

If this is all still confusing, let's start from scratch and I'll talk ya through the deal just like a fresh out of the box install!

Go to the mallory website and download the instructions for the unilite install if ya don't have 'em, all the data ya need is contained in that instruction set.
 
I don't have the original literature. I belive the shop used the ballast resistor I purchased at a local napa. There is a three wire set-up with the unilite distrbutor. I have not traced out the wiring as of yet but if you know the install backwards and forwards I would appreciate the lesson. In saying that a stock type coil is the right resistance, should I ditch the accel. Is a msd acceptable. What is the resistance of a stock mallory ballast resistor. I know I can go to the website but you obviously have experience with this setup. I have yet to pull the coil but the resistor is at 2.2 ohms now which should be an indication that it is bad. Hard to swallow at only two months. The 79 should not have a resistor wire and since the pm had the pertronix and a outboard solenoid it is obvious that there has been some wiring changes. The alternator and voltage regulator seem to be performing normally (good charge no lights flashing dimming etc) as before I was in high school the last go round revising the ignition but I do not recall having a resistor in line with the msd coil and this system works today. Is it possibe that the distributer is gone or do you reccomend starting at the resistor to the coil testing and what readings do you reccomend as I have seen about ten different scales on this
 
Let's go through this step-by-step.

Attached is the installation instructions for any unilite version used with most nearly any form of ignition system from breaker points through the addition of a cd box.

In order to prevent damage to the unilite module, it must be fed switched b+ in a "reduced" voltage format. That is the purpose of either the ballast resistor or the oem "resistor wire" (if present). Since your '79 does not have the oem resistor wire found in the earlier ihc-produced harnesses for both Scout II and pickalls, ya must add a ballast resistor to the circuit. And that is based upon your application of the accel coil described which has a nominal primary resistance when new of 1.4ohms (measure it to be certain of what it's actual value is). Anywhere between 1.2 and 1.8ohms is just fine.

The mallory #700 ballast resistor is a single element unit, nothing "special" about it at all. A ballast resistor is a ballast resistor as long as it's cold and hot value is proper for the application. The mallory #700 is rated at a nominal 0.75ohms "cold" and 1.5ohms "hot" (after fifteen minutes of constant operation). Again, that is the same factors as found with many aftermarket resistors, they will be carry a nominal rating stenciled on of "0.8ohms". Do not use a ballast resistor with a value greater than 2.8ohms or overall ignition system performance will suffer.

Ballast resistors do not fail and still read a resistance factor. Your current unit that reads 2.2ohms is simply a different value, most likely originally for a chrysler point system application. When a ballast resistor fails (extremely rare!!), it fails as an "open" (non-conductance).

Keep in mind here...we are only concerned with a mallory unilite used in conjunction with the accel coil. This is not "generic" stuff, each combination of unilite and coil is going to be different, just like as outlined in the instructions. This information has nothing to do with pertronix, or crane, or an msd mag trigger!!!! Every installation is going to be different when mixing and matching non-"system" parts.

It is very possible that the unilite module is either failing or has failed due to improper installation in the past. A simple test procedure for the unilite module is included in this instruction set.

So to review...I need to know the exact value of the ballast you will end up using, I need to know the exact primary resistance of the ignition coil you are going to use. Then we can determine actual compatibility and obtain correct installation parts if needed.

Are there other ways of setting up this distributor/system? Of course... Doing performance ignition systems needs to be approached in a building block fashion and based upon intended usage and budget. What you have right now is a very basic system and more than adequate for normal street/trail use where reliability is the primary concern.

If you integrate a mallory or msd "six series" cd box into this system, then a ballast resistor is not used. But the current accel coil you have is no where near optimum for taking full advantage of the benefits of a cd ignition unit.
 

Attachments

  • Mallory Unilite Instructions.pdf
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I will get back to you on the rest of the system. Actually some recommendations would help. I downloaded the pdf from mallory throug summitt but it only had the install instructions. The testing for the module is exactly what I need to start this troubleshooting. Thank you very much. Any suggestions for products (especially ones you guys carry) for a reliable street/trail setup with the mallory would be great.
 
Quit scruuin' with summitt for tech info, they don't know shit and only regurgitate excerpts of what is really available from the manufacturers. Both msd and mallory have outstanding technical support and FAQ on all their products. Crane is gone (some assets/product lines sucked up by pertronix), and the accel line of guapo is so limited I don't consider using the stuff except for plug cable.

Once you get the current system lined out and reliable as as a driver, I'd highly recommend integrating the mallory "six series" cd box (it's plug and play with your distributor), along with a suitable ultra-low primary resistance coil that is a match for the cd box. When installing an add-on cd box, the box controls the coil, the distributor trigger "triggers" the box, totally different compared to your current inductive ignition setup.

Sometime this coming fall, ihon will be introducing our own line of Holley distributors converted to magnetic triggers for use in either stand-alone mode with carburetion (preferably with a mallory or msd 6 box), plug and play with the afi fuel injection kit without spark control, and a simple "conversion" to allow the same distributor to be used with spark control. Idea is to invest in one distributor that is state-of-the-art but very affordable that can be used in any sv engine app if the customer later wants to try the efi route. And all modifications for each service type are reversible, nothing is rendered useless in doing these distributors.

The mallory unilite distributor is somewhat limited in what type of ignition systems it can trigger, it's a great item and the only "drop-in" distributor on the market available new that is a dedicated manufactured item and has no installation issues.
 
So the module is done. I have not yet traced the wiring back but per the instructions ground to negative terminal output 9.5 vdc with the resistor in line no change in voltage no matter how I blocked the eye. I will replace the module and purchase the active power filter as well as the mallory ballast resistor. I have to replace the cap as the center "tit" fell off when trying to clamp the cap. I have 8mm msd street fire spark plug wires installed. I see an option for a heavy duty cap and rotor assembley with hei type terminals. Msds' website has no real info on conductor type but claims 500 ohms of resistance per foot with a hellically wound conductor. So to the real questions:
I built my cables long
should I replace with a different type and make up short?
Should I replace the coil and what type would you suggest?
Should I purchase the hei type setup which would require new wires
 
Too bad about the unilight module going south! But obviously it's been dying a slow death, intermittent operation is typical failure mode for electronics.

The "street fire" helical wound (spiral wound is the same) cables I use come with the distributor end open and includes sets of both types of distributor cap terminations. The male terminal cap (some refer to that as "hei" but delco dam shore didn't invent it!!) I think the male terminal caps offer a bit more spacing for the boots to be "directed", the mallory caps (and the entire distributor body) is rather small, somewhat smaller than an oem Holley or prestolite distributor. The original design mallory distributor was first produced around 1957 and it's basic size has not changed over the years. But mallory does manufacture other high-tek distributor types today, including magnetos.

By the way, the prestolite distributor that was used in ihc applications also uses the male cap terminals.

The accel coil you have now is just fine unless you also mount a cd box at some time in the future. I'd stick with that coil now and let's get the system dialed in and reliable, then change out the coil later if you go with the cd box.

I have had issues with both the accel coil and the very similar msd and pertronix coils regarding oil leakage from the crimp at the top where the can meets the insulator,and from the center terminal. That is when the coils are mounted in the oem "lay down" position. With the exception of a higher turn ratio, all those coils are identical in construction to the oem coils that IH used originally.

I like to make my plug cables plenty long and then loom 'em in an appropriate fashion. I'll be doing a 392 of my own late this week and using one of the blingy cable guides produced for small and big block chev stuff, but they are going to be raised above the normal mounting position to keep 'em out of the way yet not interfere with the hvac system hoses. This one will receive a mag trigger-converted Holley distributor and fire an msd 6a box I picked up this past weekend. Not sure which coil I'll use yet, several are suitable but it will be a e-core coil only!
 
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So in this instance until I decide which way I want to go with the Scout (absolutely no rust very straight) I wil replace the parts add the spike module rewire the three wire plug from the distributor purchase the mallory ballast resistor (have to go online gillette wy is a hole) keep the accel coil replace the plugs gapped at about .45 to .50 and keep the wires somewhat long no reason to replace with the hei type cap and rotor. Hopefully the spike module will keep the problems at bay and brown wire to engine ground will help the rest. Wiring from switch should be good (12 vdc through wthout resisitor) add mallory resistor and drive it every day as I was before. When I get home I can decide to swap out to the built and bored 345 and possibly trans swap to granny (unsync'd) 4 speed from single axle int;l with 14" clutch take Dana 60's swap out and make this thing pull la clay is bad buisiness
 
Good plan...except....

That accel coil will be really taxed if ya "wide-gap" the plugs! There is no reason to do so. That system you have currently is still an "inductive" ignition system and opening the plug gap beyond 0.035" simply means the coil must produce much more "voltage required" than is needed at all times in order to ionize the gap.

A "wide gap" plug should only be used with a combination of a matching coil and cd ignition box. Capacitive discharge (cd) ignition systems are capable of ionizing wide gap settings on a continuous basis,...major difference. This is an apple vs. Orange kinda deal! Upgrading to a cd ignition system is a game-changer.

No "conventional" spark plug (irrespective of brand name) should ever be gap-adjusted in excess of 0.045". Any wider gap increases the risk of the failure of the ground electrode junction where welded to the plug body, if that ground electrode breaks off (more common than most folks think), then it can wreak havoc inside the combustion chambers as it transfers around the intake manifold before being finally spit out (maybe) through an open exhaust valve.

Plugs designed for "wide gap" specification are manufactured differently to allow "wide gap". We can research and determine proper heat range for a wide-gap plug application suitable for a stock ihc-produced sv engine. But there is no advantage whatsoever in doing so...

To review...an electronic trigger distributor of some design that is in excellent mechanical condition, combined with a capacitive discharge "box" of some brand name, connected to an appropriate low primary resistance e-core coil, firing spark plugs with a gap of no more than 0.045",... Is still state-of-the-art today, just as that system was nearly 30 years ago! Any IH-produced engine has about the lowest ignition system requirement of any conventional gasoline-fueled/carbureted engine out there, even when significantly warmed over. We're talking engines that never/can't see 5,000rpm, which is considered a threshold for a need for an ignition system of greater output potential. This fact flies entirely in the face of all the smokeblow generated by the manufacturers and resellers of the performance ignition system components, keep that in mind!
 
First off...thank you. Ordered the following:
ignition module
power filter
cap
mallory ballast resistor

I will trace and correct the wiring myself
install the new parts
set the champion plugs to .035

I have one last question

the po had a new Holley two barrel carb installed. It has electric choke. The power for the choke is brought from the coil primary posts. Should I rewire to another 12vdc switched source?
 
scoutpappa said:
first off...thank you. Ordered the following:
ignition module
power filter
cap
mallory ballast resistor

I will trace and correct the wiring myself
install the new parts
set the champion plugs to .035

I have one last question

the po had a new Holley two barrel carb installed. It has electric choke. The power for the choke is brought from the coil primary posts. Should I rewire to another 12vdc switched source?
Click to expand...

Now we are really getting into this deal man!!!

The electric choke cap should never be wired into the ignition coil! That could very well be what caused the unilite module to fail! Though it's more likely that the entire wiring job done by the po created the issue, it just took time to go through melt-down!

The choke cap should only be wired into a switched ignition source. It must receive a constant b+ any time the engine is running in order to "heat" the choke cap and keep it hot (or to say another way, keep the choke plate open).

Since you have an electric choke as described, I'm assuming that the carb installed is a Holley 2300, let's hope it's a list 7448 which is the 350cfm version and is the perfect aftermarket replacement carb for that application, we install those all the time!

The more we bs about this rig, the more po virus items we're gonna find! While I realize this stuff is a real pita for you since you are kinda "indisposed", working through all this kinda stuff keeps my brain exercised! If the rig (and yourself) were here in my shop, I'da pointed out all the problems right up front and you would have been totally intimidated! It happens around here all the time! That's why this stuff is a "project" and not life it'sownself!

If ya stick with it and don't get discouraged, you will end up with a rig that is correct and then ya can move on to the fun stuff!
 
Probably the weirdest part of all this is that this is Scout #8 for me. I still have the other 7. I drove my other 79 till about midway through college. Then finishing school (elec eng) and working on the road and family I have been without for about 10 years (all in storage in barns on family farm in la). I take a contract in wy and you have to have a 4wd to get around. So I buy a rusted out tub and it's great but has cancer bad. Sell it and buy this beautiful straight Scout. Now I have ignition issues (which I have never had) and have to pick my memory about what I did 10 years ago with scouts that my uncles had stripped of all emissions parts and modified drivelines (transmission from single axle yard mule = 14" clutch t18 transmission) to get it right. I have the shop manuals so will get busy getting this thing right. I will remove the wiring for the choke and wire in off the switch ckt before the coil. I also have to research the start ckt for the starter so that I can determine if I have a remote solenoid and make sure that wiring is "correct" . Funny that local super mechanic never mentioned any of this. I needed him to install the drive gear and his timing gun. Working seven days a week and working 10-13 hours a day makes this hard
 
Let's see here...from louisiana to wyoming? Can we assume ya have a role in the oil bidness? Hope someone's sendin' up care packages fulla gumbo and froglaigs! I fully understand, gillette (I've spent time there!) is kinda culture shock compared to the swamp!

Here's a tip for wiring up the choke feed...

The harness that goes down the top of the passenger side head/intake will have some deadhead wiring connectors if the po virus hasn't butchered it. One of the black wires present in the split loom bundle (black does not mean a "ground") would be a "hot" when the key switch is in the run position. That was a feed to the electrically-activated thermostat used with the oem divorced choke on some (not all) models. That wire should plug right into the choke cap terminal marked "+", it's just the right length normally. There is normally more than one "black" wire in that bundle, so use your test light to finger out which is hot with the ignition switch turned on.

That choke cap connection makes the carb/choke operation appear nearly oem! And it's enough to really confuse and fool many smognazis in some areas though that does not apply to your situation now.

Also...(you probably know this), the electrical section of the "late" Scout II manual is considerably different compared to the earlier manual set. Cts-2313 covers '78>'80 and the schematics are all separated out into sections that are much easier to deal with than the earlier stuff.
 
It is definately culture shock. Luckily I brought a lot of the basics with me and my wife was able to smuggle more in with her last trip. I'm actually usually petro-chem but am helping to sort out a basin power plant. This is the big boy "clean coal" plant that is/was in the news. Industrial electrical dcs eng actually. Hopefully all parts will be in tomorrow and then I can move on to the carb section cause I let the yokel set that and coming from the "south" my rules of thumb are no longer valid for an elevation of 4500'. I prefer -40' and 100+% humidity and 110 degree days personally. I will be back on this thread to let you know how she fares.
 
So this is where I am at. Installed all the parts. Bought the replacement accel module as it was cheaper (they own mallory now). The instructions said that with the accel 8140c (which I have) no ballast resistor was necessary wired it that way originally wired the choke to an acc from a plug that was on the fire wall and not used. Truck started immediately finished dressing all the wiring and took it around the block idled rough but lots of power with gas pulled back to the house and she died. Pulled the cap and rotor and tested per the instructions posted 12.5 vdc with the eye covered kinda got aggrivated wired the mallory ballast resistor in line and started now it wants to die when in gear. Died in the driveway the fuel filter is dirty (have a clear cheapy) will replace have not done the spark plugs yet do I need to re-time the engine as I have installed a newer module do I need to reset the carb settings (she smelled Rich had to lean the choke out when fully warm as it was still at half mast wired in the power filter installed a new cap any ideas would be appreciated really nothing left to rewire and now I have a ballast resistor in line when the instructions say not to really don't want to bring it to a shop when I don't know whats wrong (usually a good scenario to get raped) but I am running out of options
 
scoutpappa said:
so this is where I am at. Installed all the parts. Bought the replacement accel module as it was cheaper (they own mallory now). The instructions said that with the accel 8140c (which I have) no ballast resistor was necessary wired it that way originally wired the choke to an acc from a plug that was on the fire wall and not used. Truck started immediately finished dressing all the wiring and took it around the block idled rough but lots of power with gas pulled back to the house and she died. Pulled the cap and rotor and tested per the instructions posted 12.5 vdc with the eye covered kinda got aggrivated wired the mallory ballast resistor in line and started now it wants to die when in gear. Died in the driveway the fuel filter is dirty (have a clear cheapy) will replace have not done the spark plugs yet do I need to re-time the engine as I have installed a newer module do I need to reset the carb settings (she smelled Rich had to lean the choke out when fully warm as it was still at half mast wired in the power filter installed a new cap any ideas would be appreciated really nothing left to rewire and now I have a ballast resistor in line when the instructions say not to really don't want to bring it to a shop when I don't know whats wrong (usually a good scenario to get raped) but I am running out of options
Click to expand...

Actually the brands of mallory, accel, mr. Gasket, hayes, etc. Are now part of the prestolite performance group of companies. But their actual product lines are not shared or dual-labeled. Each company is stand-alone in producing and marketing their own unique product lines, even though in essence...accel and mallory electric are bitter competitors in some areas. Much of accel production is offshore. Most of mallory production is still done in the u.s. The accel brand is price-leader positioned now, the mallory stuff competes directly with msd (msd actually private labels some mallory).

A suitable ballast resistor must be used with the unilite distributor trigger, no way around that unless you also install a cd box. Look at that as it's own "system" which is going to talk to the coil. And...this type system is nothing like what would be oem with either breaker point distributor or an electronic trigger distributor other than a unilite technology.

The information regarding the accel 8140c coil is totally wrong and misleading, in order to use any coil with the unilite distributor system, a ballast resistor or a suitable resistor wire of the correct value...1.4>1.8ohms must be wired with the distributor exactly as shown on page #2 of the mallory instructions for the unilite installation. Again, this installation wire run is totally different as compared to any stock coil/distributor setup.

The ballast is used with the unilite module to control primary side current through the unilite module. Inna stock system, the ballast is used to control current on the primary side of the coil! Big difference! Forget everything you know about "stock" ignition system wiring, the unilte setup is it's own deal, just as a cd box is it's own deal.

Any time any component in a distributor is disturbed/removed/replaced/adjusted/etc., (whether electro-mechanical or solid state of some design), there is a setup process involved regarding mounting the device internally. Either a dwell setting to make, a "reluctor air gap" to adjust, a trigger gap to adjust, or a clearance factor between the unilite module and it's companion shutter wheel, or something. Then, since the relationship between the device components has now changed minutely due to the part replacement process, the actual base timing must be re-set (or at least verified as being within spec). Same thing any time a distributor is removed and then replaced, there is no way to place it back in the exact same position, therefore we simply re-check the base timing and adjust and lock down as needed.

Once the ignition is installed and timed correctly and the engine warmed up, then the carburetor idle mixtures and curb idle speed is set. Always...you must have the ignition dialed in before adjusting any carburetor function. Ignition affects carburetion...carburetion does not affect ignition.

Review those mallory unilite instructions again, wire it all up exactly like the instructions say using the ballast resistor (make sure the resistor is still ok and within value). The only difference you see in those instructions is the line art for the coil, the instructions show a mallory promaster coil, however, the positive and negative terminals are exactly the same as any other coil, the wiring is the same, note where the ballast resistor is wired in!
 
The ballast resistor is wired in as mallory shows and the ballast resistor is a mallory product the two parts (ignition modules) are identical except in color I guess that is what threw me the most is that the accel instructions stated the exact coil p/n with all that said I think I will go old school and adjust the timing by "ear" for the moment I read your performance tune section and will revert back to my uncles advice a timing gun is for factory shit from there I will read up on the carb section and perhaps start a thread in the end I need it to drive to a shop (instead of dragging it behind a truck) and let a new mechanic finish the tune up and carb setting I'll let you know tomorrow and I will research why the "test" did not show a voltage drop but the truck fired up??
 
If the "new" carb is a list 7448 Holley, for your current location/altitude the setup I'd use is:

1) adjust float/fuel level so that it's 1/32" (nominal) below the bottom of the thread on the sight hole in the side of the bowl...do this first.

2) I'd run a #65 power valve. That should be what is in it if the carb was a new one out of the box.

3) original main jets would be #61 from the factory. I'd start off with #56 or #57.

4) out of the box, that carb should have #85 power valve which is ok, but a #45 would be better.

5) electric choke cap should be set one tick Mark to the "Rich" direction form the exact middle position (long tick Mark).

All this tuning setup is based upon the use of autolite #85 (or #303) spark plugs or equivalent heat range. Don't change heat range or all the tuning stuff goes to hell!
 
Alright!!! We are running and running well. The plugs are changed and I used a standard champion plug cu core with a .035" gap (every plug I pulled was black as hell and gapped differently from .028-.038 errrr) the ballast resistor, power filter, and new module are wired according to the mallory instructions. All spark plug wire (msd 8mm spiral core) are new, checked and marshalled (one of the plug wires looked to have been pulled out by the steering shaft which is why she wouldn't run yesterday I think) the choke is wired in to a different (and hopefully) unused stock acc ckt she stills smells Rich to me so I guess we are done with the electrical and on to the timing and carb sections to dial this baby in once again thank you for the time, information, advice and patience for dealing with someone who reads the directions (should have known they weren't right ;) )
 
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