Ignition miss w/ erratic tach after coil failed.

[UkieDime]

So I'm cruising up the 5 in my 1970 2 door 510 when I stalled in traffic and had a crank-no start condition. Looked like my points-"Did he say points?" were closed. Pulled my D411-88 single point distributor and swapped 2 sets of points and a condenser-no good. Towed to work. Installed an MSD box and L20 distributor that ran on a donor engine car years ago with a Master Blaster coil-crank no start. I work at a Ford Dealer with a couple really smart Driveability techs-head scratcher. Install just the MSD coil-started for a moment. Got a coil from Carquest-'use with ballast resistor"-fired right up. I have been driving this car often and hard for 10 years and have never seen a ballast resistor though I have been running a ballast coil the whole time. Recently opened up the whole harness looking for a twice a year gremlin-fixed but not related.

 

Driving the car home it started missing right away....limped it home-had to run low gear high RPM. Found I had the coil to condenser wire touching the housing-it was sparking through the distributor body!! (Idiot). Just put in new points, set dwell and timing. Ran awesome for 4 miles then a slight hesitation. Note the tachometer has started to "float" at idle. I pulled the tach and ran a separate ground-no difference. 

So there it is-70 510, L20B with a A87 Rebello built peanut head, L16 single point distributor, "use with ballast" coil-no ballast to be found, Stewart Warner 1980's gauges. I have 2 EL distributors-one is much larger than the other-no numbers and I assume they both ran with the MSD box.

 

Guys at work think it's a ground problem-the floating tachometer?? Side note I pulled the tach about 6 months ago to replace the bulb and it shocked me-I believe it shocked me again today pulling for a ground. Anyway-any and all thoughts would be appreciated greatly. I'm 55 and though I feel about 25 years old cruisin' the Dime I was contemplating putting it up on Craigslist for around 12K so in one respect I'm glad it failed on me now.

 

Thanks, Nestor     -forgot I also got a "Non ballast' coil-have not installed it.

 

 

[datzenmike]

If running points you need a ballast resister with a points coil. If not you are running a full 12-14 volts on the coil and points. If the coil does not fry the points will arc badly and wear out much sooner. In as little as 50 miles. If it started up and ran well after replacing then started to run bad.... this is a good indication. Arced and burned points won't make good contact or intermittent contact ... another reason the tach is confused. File the points and I bet it fires up and runs for another few miles before crapping.

 

 

Not familiar with how an MSG works but you can't get a shock from the stock points and tach. If MSG, don't you need a magnetic pick up to trigger it?

 

If you have an EI distributor there are two kinds. One has the igniter module inside the car, (remote igniter) the other has a miniaturized igniter module mounted on the side called a 'matchbox'. If you have a matchbox distributor you certainly don't need an MSG to fire the coil. This just ads complexity. All EI distributors are the same size, in fact all L20B distributors are the same size, EI or points. If one is slightly smaller then it's an earlier L16/18 points dizzy.

[UkieDime]

Datzenmike although I don't see a ballast anywhere, and have run it that way for years........what do you think of installing the Non Ballast ignition coil? I was going to return it if I never installed it. Again-the original coil said use with ballast-I installed the same type coil and didn't change anything but it is not running correctly.

[UkieDime]

Just when out with a test light. With key ON I have power to both sides of the coil-then i unplug the connector at the distributor and have power to + and very weak to -. Also on the negative side I have-I think-a red tach feed and a black wire, with the black wire pulled there is power to both sides of the coil-then just + reconnected. One black/green feed to + side of coil.

 

Back to the ballast Mike-I have looked at some threads......can you break it down SUPER simple how to add the ballast resistor for me? 

 

Thanks again, Nestor

[datzenmike]

Power from the ignition switch goes to the coil + side. The coil - side goes to the points that open and close to ground. When closed, current flows through the coil to ground generating a strong magnetic field around the coil's core. When the points open, current stops and the magnetic field collapses through the secondary wiring in the coil and this induces a high voltage spark.

 

There are two power sources to the coil positive side.

 

On an early 510 the Black/White stripe wire is 'hot' in the On and the START position of the ignition switch and is connected to one side of the ballast resistor. The other side of the ballast goes to the coil + side. The ballast resistance drops the applied voltage down to about 6-8 volts. This is there at all times the key is on or starting.

 

The other wire has a Black/Blue stripe and is 'hot' only in the START position. This wire is connected directly to the coil + side.

 

What happens is 12 volts is supplied to the coil during start to provide extra voltage for extra spark voltage during cold starts and when the starter is drawing a lot of current. When the engine starts up, and the key released, it only gets the 6-8 volts from the ballast resistor. This is plenty of current to keep a running engine running. Why not run 12 volts at all times? Well the points would burn up and/or the coil would over heat from all the extra current flowing through it. You could find a coil that has an internal ballast.

 

Points coils have an internal primary resistance of from 1 to 1 1/2 Ohms. The Ballast resistor is about the same so the total resistance is about 2-3 Ohms. 

[john510]

When it starts running bad is the coil hot to the touch ? Like Mike said,points have to have the ballast resistor.I think ive seen an electronic distributor that had a resistor also,the old style remote black box.

[DanielC]

The more current you switch with points, the shorter the life span of the points.  The ballast resistor eases the wear on the points as much as limiting current through the coil.

 

I would suspect a problem with the tachometer.  Disconnect it from the coil, see if that changes anything.

 

Comparing OEM Nissan to aftermarket coils, the quality of the Nissan stuff is much better.  I am pretty sure the same applies to OEM Ford stuff, too.  Try to get a Nissan matchbox distributor and coil.

 

This is the wiring diagram on a Datsun 521.  I believe the ignition wiring is the same on 521 trucks, and 510 cars. 

There are two wires that can supply current to the ignition system.  The car (truck) runs on power from a black wire, with a white stripe.  This wire connects to the ballast resistor, and on the other side of the ballast resistor, a black with a red  stripe wire goes to coil positive.  Coil negative is grounded by the points, in the distributor.  When you are cranking the engine, power comes directly from the key switch to coil positive, on the black with a red stripe wire.  

 

 

Every ignition system works the same way.  Power is applied to a coil.  The coil is grounded by a switch, controlled by the engine, or a computer.  When it is time for a spark, the ground is switched off.  When power is applied to a coil, a magnetic field builds up in the coil.  It takes a little time for this magnetic field to build.   As long as current flows in the coil, the magnetic field is there.  When the current is switched off, the magnetic field collapses, quickly.   the energy stored in the magnetic field is diverted to the spark plugs.

 

 

Points are finicky.  The points have to make a very good connection to ground, or not enough current will flow into the coil to make a strong spark.  If the negative side of the coil has any kind of partial connection to ground, it will divert some of the energy from the collapsing magnetic field.  In addition with points, if the gap is too small, they do not open far enough to prevent the spark from happening in the points.  This quickly destroys the point contact surface, and robs energy from the spark at the plug.  If the gap of the points is too wide, the points are not closed long enough for the magnetic field to build completely.   You can check point gap with a feeler gauge, about .020 of an inch, fully open.  Another method of checking point gap is with a dwell meter.  You want 49 to 55 degrees of dwell.  Another possible cause of poor spark from a points system is a bad condenser.  this is a small round can on the side of the distributor with a wire coming out of one end.  It's job is to absorb some of the energy from the points starting to open until the points open far enough to not spark

[flatcat19]

Rebello built head....points ignition.

 

 

 

What EI dizzy(s) do you have? Pics help a lot in these cases.

Non-ballast coil is the coil you want with the EI system.

MSD makes a harness that plugs right in between their box and the HEI style dizzy. Nothing else needed short of the coil-which you already have.

 

 

I'm with a couple of other people. Toss the tach.

[datzenmike]

Erratic tach is from erratic ignition. New points ran better for a while until they burned up.

[UkieDime]

Thank you for your input and knowledge. I went ahead and installed the non ballast coil-which I was unsure meant internally ballasted or not-and drove the car 10-12 miles with perfect operation. Again-the coil that died ran the car for 10+ years and stated "with external ballast" yet I don't see one. I assume the latest coil is has an internal ballast and will update it's operation after some more miles. I never tried to install the MSD Electronic ignition because the car always ran so well as it was set up. Greatly appreciate the help-the knowledge on this forum is incredible.

 

Regards, Nestor

[datzenmike]

I think you would need an EI distributor to run an MSD and if you have EI you would not need it. Yes I am following this, keep us updated. So you have points in it now?

[banzai510(hainz)]

Ukie Dime

 

lets make this simple. If running Points igniton or a a Pertronix ignition conversion your run a Point Coil in the  say above 1.2 ohms to like 3 ohms. this cuts the current to the Points or Pertronix and keeps the coil from getting HOT.

Also with the point setup there is a HOT Start wire that bypasses the ballast and goes to the + side coil. this is for cold starts to get the car running then when key switch snaps back to go the power tgoes thru the ballast then to the + side coil.

 

 

I never had a coil go bad!!!!!!!!!   Just buy a coil from Rockauto.com.

 

Dual Points suck and go thru a 3rs gear switch relay system. I just run a single point and use a Pertronix conversion. Other use a matchbox but use the matching mount also!!!!!!!!!!!! and use a 78/79 200sx/620 EI coil.  bypass the resisitor. these will be a lower .7 ohms.

 

a point coil from a 68-72 510 will be 1.6 ohms and the ballast is another 1.6 ohms

 

 

Now changeing all this shit around confused me and it pretty simple you get spark or you dont at the end of the coil wire.

 

 

Persoanlly I think those MSD boxes are junk and goes to 1 spark after 3k anyways so I dont see the point in them. Ever see the solder jobs inside them?

 

 

Now tell us what dist is in there.

Throw the MSD in the river. your hjust adding extra shit to break later

[racerx]

Msd box is only good for a beef up engine. Other than that a single point, pertronix or matchbox is good enough.

[UkieDime]

As we speak: Single point L16 distributor with points. Blue wire Nissan condenser. Yesterday switched to the "External resistor not required"coil. Was hesitant to install it thinking it would burn up the points right away-but so far so good. The "external resistor required" coil was failing and causing the tach to float-not an issue with the coil on it now. 

 

Hainz I liked your video on swapping heads-excellent. Back in the day.......late 70's early 80's many people I gleaned information from said to Always carry a spare coil. I have to tell you guys I have been in New Car Dealerships for 30 years-cars have always come in on the hook for any variety of reasons many with 200-500 miles-batteries, transmissions, fuel pumps etc. I drove this 510 across the country twice without batting an eye and think my 46 year old 510 is as rock solid and dependable as most vehicles on the road-plus of course-the thumbs up and honks......."Is that a Fiat.?"

 

Too hot this week to cruise the Dime but I will let you know how the points/ignition system is holding up. 

[datzenmike]

I have never seen a failed coil, ever. It just doesn't happen. But what's the first thing people do when there is a guessed at ignition problem? They throw on some made in China junk and throw away a perfectly good quality coil hoping to get lucky. W in TF?

[racerx]

2 coils have gone on me, 20 years ago, 65 mustang and datsun 510. What i learned is to ohm out or test before buying on, unless u buy higher voltage one

[banzai510(hainz)]

monitor the point if pits really fast and you cut out on the top end I would think the points are getting satuarated with to much current.

 

really you need the specs of the coil. point want at least 3.2 ohms(3 will work) as that the stock resistance . with the stock coil and ballast.

 

 

I run a Accell super coil on all my Datsun but in the instruction it says use the stock ballast and coil. But in the kit there is also another ballast resisitor.  Many people dont use this and then it give proplems of burning up points. So since I use a Pertronix I keep it the same set up. If one measure the volttage right at the coil its like only 3 volts as the 2 other ballastaresisitrs drop that much voltage.

 

 

also people using Malloery Unitlites back in the day would pop the modules. But in the kits says to use the stock coil and ballast. Many people would but a differtn type coil and remove the ballast thus popping the module.

 

But its mostly for looks. Im sure the stock coil is fine