Jacobs Ignition Coil - Advice Please

tumalo · 01-23-2003, 08:52 PM

Just got a Jacobs Energy/Ultra coil and figured it would be as simple as swapping out the old with the new. On the bottom of the coil there is a sticker talking about adding an External Ballast Resistor for applications like Bosch and Lucas. How do I identify if I have/need an External Ballast and do you have any recommendations??

Jacobs also claims I can run with a bigger Sparkplug Gap . . . what would the benefits be to running a bigger gap?

Many thanks in advance for any information you can provide.

Best Regards,
Chuck

justin · justin's Garage

What year is this car? What voltage is the coil rated at?

tumalo · 01-23-2003, 09:30 PM

No information on the packaging and nothing on the coil. Performance Products marketing mumbo jumbo states "This patented design increases or decreases spark energy based on the demands of the engine. The coil produces a consistent 28,000 volts, regardless of plug condition, heat or engine rpm. It features ultra-rugged construction and heat conductivity"

tumalo · 01-23-2003, 09:31 PM

sorry .. .forgot the model year . . .1987

justin · justin's Garage

Ok, I don't think you need a resistor.BUT you might want to e-mail Jacobs to be sure,I have a Accel coil on my 83' with no problems.

tumalo · 01-23-2003, 09:40 PM

I'll confirm with them tomorrow. Did you notice any difference going with a better coil?

Any suggestions if I should increase the gap in my sparkplugs? I'm curious what the perf benefits would be. Jacobs indicates I can increase the gap by .010 over standard

Many thanks again for your advice!
Chuck

1.2gees · 1.2gees's Garage

I would increase the gap slightly but no big deal. I used this coild (along with other ignition stuff) on my 84 for a while without any problems but I'd like to see what you'll hear before I install it on my turbo so please let us know what you find out from Jacobs.
Thanks
Ahmet

AFJuvat · 03:26 AM

Used them both (jacobs coil and wires) with good success.

They have you open the gap because the coil is "hotter" than stock - allowing a more powerful spark - opening up the gap takes advantage of this.

AFJuvat

Lawrence Coppari · 01-24-2003, 03:20 AM

I bought their entire system a couple of years ago. Darn thing did not work properly after about 5 minutes. I eventually returned it for a full refund. I was greatly disappointed. But for those 5 minutes, the engine was silky smooth. I imagine I got a defective one.

scottmandue · 01-24-2003, 09:15 AM

Okay guys I bought one of these a few years back but the ballast resister note scared me off from installing it, I was a-feared that it might melt down parts of my electrical system thus being more trouble than it was worth.

IIRC it was a chrome and blue round coil.

SO...
Chuck, AFJuvat, Ahmet:
Is this the same coil you are talking about?
Can I install it without the resistor?
The coil I have is a slightly smaller diameter how did you fit it?(I have vowed not to use duct tape on my Porsche)

TIA
Scott

tumalo · 01-24-2003, 09:37 AM

That's what I have . . . its' the "ultra". I'm still trying to track down if I can install without a resistor. As for fit, I purchased the Jacobs mounting bracket that goes along with it (extra $5 from Performance Products.

tumalo · 01-24-2003, 09:52 AM

Called Perf Products . . . and didn't even get to finish my sentence before he was giving the answer. Guess they get a lot of calls about it!

Anywhoo, said the ballast is for cars with points. 87 didn't have points so don't need it. If you've got points, don't use. I assume it will fry them.

Cheers!

AFJuvat · 01-24-2003, 09:57 AM

No 944 has points.

scottmandue · 01-24-2003, 10:09 AM

Way cool guys!

Now I have dig through the garbage dump... I mean my garage to find the silly thing.
Ah yet another project!

SoCal Driver · SoCal Driver's Garage

Quote:

Originally posted by AFJuvat
No 944 has points.

Electronic points!

That is the transistors required to ground the "other" side of the coil. Might check this out with those that tear into the DME brains to see if it can handle the switching loads.

profssr2017 · 01-24-2003, 10:51 AM

Re: Ballast Resisters

They were used on points to reduce the voltage going to the point contacts once the engine warmed up. This was done to extend the life of the points. The ballast resistor provided 12 volts to start a cold engine, and dropped to six volts as the resistor heated up. Triumphs used to use them, but discontinued in the '70s as point contact material improved. Like you guys have said: no points = no ballast resistor.

I love a good working electronic ignition. But I can't do a thing to it if it doesn't work. At least I was able to reset points.

SoCal Driver · SoCal Driver's Garage

Quote:

Originally posted by profssr2017

I love a good working electronic ignition. But I can't do a thing to it if it doesn't work. At least I was able to reset points.

Dewl meters!

Had a Snap-On until my garage was burgled 16 year ago. Then no reason to replace it because of the electronics in the newer cars.

profssr2017 · 01-24-2003, 11:17 AM

Ah, Yes. The lovely dwell meter. Took me the longest time to figure out what that thing actually did. I still have one in one of my tool chests. Haven't used it since the late '70's. Wonder if it'll still work. In the 60's we used to set VW points with a match book cover. It was close enough to allow the engine to run. That's the main advantage of a de-tuned engine. It'll almost always run if you're even close to the right setting.

tumalo · 01-25-2003, 12:52 PM

Thanks to all for your advice/input. Coil is installed and . . . no noticable difference but time will tell. Helpful advice for you though, the coil is smaller than the bracket so you will need some type of shim material (take sheet metal and cut a strip).

The Jacobs add on bracket does not seem to work on the 924S because the mounts are different. I ordered the bracket prior to learning this, figured it would sit on my shelf and rot so used it for my shim. Just cut off the mounting strips - worked like a charm.

Cheers!

scottmandue · 01-25-2003, 01:52 PM

Well thanks, just saved me $5 to buy the bracket that will not fit.
I bought the coil with wire/cap/rotor/plug and gave her a tune up when I first bought the car. Car had a slight stumble between 3K and 4K rpm. After diveing her for a while many small problems like this started to disapear. Leads me to believe the car sat idle for a long while before I bought it. Proof to me that it is not a good idea to let these cars sit for long periods of time.