NAPA coil

[Mark S]

Does anyone have a NAPA part number for an oil filled coil appropriate for the Atomic 4? I went to fire up the engine this afternoon and she turned over just fine but there was no ignition whatsoever. I pulled a plug (brand new) and noted fuel on the tip. I had no helper so I couldn't check for spark to the block from the secondary out of the coil. This same situation occurred in the spring two or so years ago when I went to start the engine for the first time. I installed my spare coil and that solved the problem. I have the Ignitor electronic ignition and yesterday installed, as I do every spring, a new cap, rotor, plugs and wires. I checked and double checked those installations and they were all performed correctly. If I can get a NAPA coil tomorrow I can see if this is the problem.

Thanks.

Mark S

[Ball Racing]

Just ask for the coil that does not require a ballast resistor.(even though you should add a small one)
Thats the coil I buy from napa, and I just ask.

[ndutton]

You need an internal resistance coil plus a little more. Most internal resistance coils come in one of two flavors: 1.5Ω and 3.0Ω. With your Ignitor ignition you need to be in the neighborhood of 4Ω so an additional ballast resistor is indicated.

With a 3Ω coil the NAPA brand (Echlin) ICR 5500 resistor is a suitable choice. There are others. You want to be close to 1Ω on the resistor or 4Ω overall, coil + resistor. They are wired in series.

edit:
The Moyer coil already has the proper internal resistance without the need for a ballast resistor. I realize you do not have the luxury of (shipping) time but I didn't want this to go unmentioned. Don really takes good care of us.

Good luck

[marthur]

Give the guy at the parts desk one of these numbers. They will be able to match up a coil that will work:

Borg Warner E40BAP
Borg Warner E502P
BWD E81
Delco Remy D15
Delco 070FLX
Echlin IC64
Echlin IC14
Filko UC101HS
Mitech OI-126
NAPA IC14 (internal resistance)
NAPA IC64SB
Niehoff DR-180 (standard)
Niehoff UN171 (epoxy heavy duty)
Pertronix 40511
Standard UC15
Wells C804
Zenith 5-501BB

If you are traveling to Canada, you can ask for NAPA IC14 (Number specific to Canadian NAPA stores. Probably the Echlin IC14 sold in the US).

The coils in bold are coils that I have personally used. To double check the specs you need a 12 V primary winding, internal resistance of 3-4 volts. You actually want closer to 4 volts, but you may have to add the external resistor Niel mentions to get there.

Good hunting,

Mike

[joe_db]

I am using the Standard UC15. A lot of trial, error, and burned out coils went into finding out BOTH the Moyer and Indigo electronic ignitions will eat up coils with anything less than 4 ohms resistance.

[Mark S]

Thanks, guys. The info has been very helpful. The local NAPA has the Echlin IC14 so I'll give that a shot.

Neil, I appreciate the plug for Don. I always get all my stuff from him except spark plugs, but, as you observed, I don't want to wait to the end of the week. Always in a rush, I guess.

Joe, your comment about the electronic ignitions got me thinking about the timing of my coil failures. We bought the boat in 2008; installed the Ignitor in 2009; first coil failure was spring 2011; and second coil failure now in 2013. That graphs a straight line. Does this comport with others' experiences?

Mark

[Mark S]

Mike, I got the Echlin IC14. When you use this coil, do you use external ballast resistance? I assume I'd find the coil's resistance by passing an ohmmeter across the terminals.

Mark

[Ball Racing]

I use the ICR5500 resistor with my napa 3 ohm coil.

[Mark S]

Of course, all I had to do was take the coil out of the box and read the label where it says "No External Resistor Required."

Daniel, how do you install the resistor you use?

Mark

I see Neil mentioned wiring in series. I should follow Mother's advice and "read the text."

[marthur]

Well, I am thinking of adding the external resistor.

I have only had one coil failure-that was about 5 years after adding EI. I had a second coil leak some oil, but it was fully functional. I am wondering if that was a manufacturing defect with the seal on the metal can because it happened pretty fast.

I am currently running a coil with 3.6 ohms internal resistance as measured by an Ohm meter across the terminals. A question I have for the group is how warm should these coils be after running for an hour or two in an enclosed engine space?

[Mo]

Thanks for that number Daniel...I'm going to pick one up as a spare. Is that one about 1 ohm?

[Mo]

Mike, they get pretty hot. I've not had one go out on me but I did run about 6 hrs straight many times. I can't hold my fingers on it at the end of a trip. Oil filled coils heat up and dissipate heat by design. I bought a new infrared thermometer a couple of weeks back...should be able to get an accurate reading once the boat gets in the water and on a run.

[ndutton]

Of course, all I had to do was take the coil out of the box and read the label where it says "No External Resistor Required.

Just because it says so doesn't make it necessarily true for our application. You need to actually measure the resistance across the terminals and if it's not more than 3.6Ω you should add a resistor regardless of what the label might say. Combined 4Ω is a good round number. I have 4.185Ω combined and zero issues for years.

A question I have for the group is how warm should these coils be after running for an hour or two in an enclosed engine space?

See graph. The lines were with an alternator output of 14.7V, the X was a spot check after the regulator was replaced for a 14.0V output, resistor still installed. As shown, several factors contribute to coil operating temp.

Thanks for that number Daniel...I'm going to pick one up as a spare. Is that one about 1 ohm?

The Echlin ICR 5500 is 0.885Ω

[Mo]

Thanks Neil....on the ball as usual

[joe_db]

My coils died so often my wife would not leave the dock unless I showed her the spare that WAS going to get used. If memory serves, the routine coil deaths pretty much ended when everyone with electronic ignition added ballast resistors. I had the Indigo system, but the Moyer/Pertronix was just as bad. Pertonix's OWN suggested coil would burn out! I fiuged I was getting about 100 hours per coil

Thanks, guys. The info has been very helpful. The local NAPA has the Echlin IC14 so I'll give that a shot.

Neil, I appreciate the plug for Don. I always get all my stuff from him except spark plugs, but, as you observed, I don't want to wait to the end of the week. Always in a rush, I guess.

Joe, your comment about the electronic ignitions got me thinking about the timing of my coil failures. We bought the boat in 2008; installed the Ignitor in 2009; first coil failure was spring 2011; and second coil failure now in 2013. That graphs a straight line. Does this comport with others' experiences?

Mark