Igntion Coil question ????

[BEETLE]

Hello,

I just received a package today from RockAuto.com about an Ignition Coil I ordered from them. It is for 1984 Isuzu pickup w/ 1.9 liter gasoline engine. I was shocked when I saw what's inside the package, it's totally different from the old ignition coil. The old one is round but the new one I received is square. Is this latest ignition coil being produced for this truck?
There is no picture of the item on their site. It only says OEM replacement w/ Denso coil. Please see picture below.

Ignition Coil

RockAuto site



Thanks in advance

 

[stevejones]

Why did u pick the only one without a pic?

 

[BEETLE]

Hi stevejones,

I thought they were all the same size & shape...The site says "OEM replacement w/ Denso coil." The original old coil says NipponDenso on it. Thanks

 

[Nukeman7]

They sent you the wrong part. It is not compatible with your Isuzu. Go to your local auto parts store and have them show you what it should look like.

 

[sicko]

Have you contacted RockAuto? That should be your first step. From my experience, RockAuto has excellent customer service and they'll take care of you.

 

[1 FMF]

http://en.wikipedia.org/wiki/Magnetic_core

what you got was an E style coil, the shape is better for spark output vs the traditional canister style coils.
all motors today use an E style coil, the GM LS motors with coil per plug with the coil mounted on the valve cover is an example. you can make a smaller coil that performs better with that shape, the iron core is wrapped more to generate the spark.... same as an coil on a lawnmower engine.
if you can mount it and hook it up then i would use it. if it's too much trouble and it makes more sense to use an old style canister coil then consider returning it... depending on what it cost and return shipping and all that.

the old canister style coils can be had easily anywhere,
so consider calling around locally for one before mail ordering... the big problem is most stores don't know anything but what the computer tells them for year make model.
for your 1984 isuzu what will matter is if the ignition is electronic or points/condenser, and what the internal resistance of the coil is supposed to be. there's a thing called a resistor wire that may or may not be on your truck, which lowers voltage delivered to the + side of the coil when points/condenser is used. you should figure out if you have that so you order the right coil. and then if you do have a points ignition and not electronic, consider buying a pertronix electronic igntion module for it and get their coil for it.

 

[Trav]

+1 This truck has electronic ignition with a coil resistor.
The op can use the coil they sent if it has a bracket or a good alternative is the one from SMP
It is a Blue Streak which was their best product line. # UC12X.

 

[SteveSRT8]

Originally Posted By: Trav
+1 This truck has electronic ignition with a coil resistor.
The op can use the coil they sent if it has a bracket or a good alternative is the one from SMP
It is a Blue Streak which was their best product line. # UC12X.


Trav,

Is that the line where the parts were weird blue plastic? I remember a great distributor cap for my Chevelle that was nifty blue plastic and lasted a long time, maybe had brass contacts?

 

[Trav]

Thats it. Blue Streak was the best of the best, it was Standards top shelf.
Everything plastic was blue (coils and a few other parts also), even the cam block on the points.
Now the line only exist in Canada IIRC but there are lots of NOS around.

 

[Yah-Tah-Hey]

Blue Streak was the way to go when one was doing upkeep on point ignition systems. I have several end wrenches that say Blue Streak on them. Anyone ever see these wrenches?

 

[BEETLE]

To: 1 FMF & Trav -
Until today, I decided to keep the ignition coil. Thanks for the detailed explanation that the coil will work on my truck. I was disappointed at first when I got it, since returning it to RockAuto would cost me an arm & a leg for the postage. But now I am excited to install it. Upon installation I encountered a problem...the canister coil has (+) & (-) terminals. The new one has 3 connectors. I do not see any + or - sign. How do I tell using the multi-tester which is positive or negative? Thanks in advance

E style Coil

 

[Trav]

The unmarked connector really throws a monkey wrench into the works. This is not just a universal coil which is a different shape, it seems vehicle specific.
What reading do you get at the 2 spade terminals and the L shaped terminal and the 2 others?

 

[1 FMF]

http://beru.federalmogul.com/sites/default/files/ti_07_ignition_coils_gb_2013_lowres_0.pdf

are you sure that third angled pin is not a latch for the connector that was designed to plug on to the coil?
normally an ignition coil has only two electrical terminals, and all that happens is an electric current runs through it to generate a magnetic field around the iron. it's when that electric current is shut off, that the magnetic field collapses and generates a high voltage spark on the secondary winding which is connected to the spark plug wire.
for the old canister coils whose 2 terminals were marked + and -, I'm not sure if it really mattered which one the hot lead went to. All it is is a hot lead to one terminal on the primary winding, and the other side goes to switched ground... the switch being the breaker points or electronic ignition module breaking the electric circuit at the right time to generate the spark into the secondary output winding of the coil.
if your old canister coil did still work and wasn't totally shot not producing spark, measure the resistance in ohms across its + and - terminals, without anything connected to it. it should measure out at 1 to 5 ohms. your replacement coil should be close to or higher than what the original was... if resistance is higher that's ok because that means less current and it won't blow the electronic ignition module that's switching it. it's when the igntion module expects a coil having primary resistance of say 2-3 ohms to keep current in check, and you use a high performance coil having a primary resistance of less than 1 ohm you blow the igntion module.

 

[1 FMF]

the way it works is when the electric current is shut off on the primary winding side of the coil the magnetic field collapses around the iron and generates the huge voltage into the secondary winding that leads out the spark plug wire.

but what also happens is a voltage spike in the primary side winding, and it would go back out on both the + and - leads and the wires connected to them. the spike is no where near as great as the secondary spark plug side, but it's significant. now "i think" the old canister coils had a diode in them allowing current to flow only one way, thus leading to a + and - terminal. This then means you only need to worry about the spike going off the negative side of the coil... which was a good thing because that's where you connect your tachometer signal wire and that voltage spike/pulse correlated to engine rpm. the old breaker point ignition systems used a condenser to soak up the unwanted voltage spike on the primary side so it wouldn't go out onto the rest of the 12v electrical system... and cause your headlights to pulse for instance... i don't remember if the condenser was connected on the + side of the coil then.

so, all that said, if your old coil canister was still operational find out if there is a diode in it. and if there's a diode in the new coil. use a multimeter with a diode checking function, or measure resistance both ways across the coil terminals. if you get a resistance reading one way but an open circuit the other way then there's a diode present. that'll help you know what terminal on the new coil is + and -, if it matters. my guess is yes because you don't want the voltage spike going back out on the + hot lead connection, and if it goes out on the negative lead going to the ignition module, the ignition modules are usually designed to handle that spike. At least that's how the pertronix ignition modules work, so i assume isuzu does basically the same thing. there's not much you can do differently... as long as the new coil is not a CDI coil.

 

[Trav]

Like you say i think the L shaped pin/bracket or whatever it is is just to hold it in.
I think the 2 spades are the +-.
There is no way to tell AFAIK with a VOM which is + you need to do that with a pencil at the secondary cable cranking or an Analog VOM at the plug engine cranking. It matters which wire is on the + side.

 

[asand1]

Or figure out what the coil fits and look at the accompanying wiring diagram.

 

[paulo57509]

Originally Posted By: HosteenJorje
Blue Streak was the way to go when one was doing upkeep on point ignition systems. I have several end wrenches that say Blue Streak on them. Anyone ever see these wrenches?


Are you sure they didn't say "Blue Point?"

 

[Trav]

I think i saw a small set of ignition wrenches that were branded Blue Streak on the plastic tool holder roll as well as the little hex wrench that was used for GM points.
Its got be all of 40 years ago, i couldn't swear to it. possibly a promo item?

 

[asand1]

Blue point is the snap-on economy brand.