Ignition Coil

[deadmeat]

My 1979 spider has 34k original miles, was garaged it's whole life (one owner before me). I am thrilled to own my first spider. I'm brand spanking new to the forums. I found you today while working on my mag pickup. My tach is not working right and that was my first guess. After following the shop manual, I found that my coil was out of tolerance. I was reading .90 Ohms from post to post, which is higher than the .81 max. Since the tach reads off the neg post on the coil, I'm guessing this is my problem. I found an exact replacement at International Auto Parts.

HOWEVER, I am wondering if there is a newer "dry" type coil that will provide better performance at a better price (the Marelli is $250). I don't want to throw off any of the ignition system by changing the stock coil, so I would appreciate any advice from anyone who has experience replacing the coil.

Thanks, Scott

[124JOE]

hello and welcome
check your grounds just above the ING switch
and why buy a expencive coil?are you racing
i was told you can use the old GM style $12



want to post pics?

[deadmeat]

The only reason I would buy the expensive coil is that it is the stock one. I'd much rather save my pennies for other things. I'll check the ground and let you know. As for coils, it doesn't sound like swapping the original Marelli for a cheaper one will affect anything else. Is that correct?

[124JOE]

i remember someone saying these cars had the same style coils as an old GM coil
so they would be easy to fix here in the USA

[deadmeat]

So how do I post pics on here? Can't seem to make them "stick" here.

EDIT: I See you Sig line, now. I don't use photobucket, but I'll work through it later and tag them.

[124JOE]

do you use any photo housing sites?

[deadmeat]

Just Facebook

[maytag]

deadmeat:
you can use ANY modern coil, so long as it was designed for 12v!
No reason to spring for the original Marelli unit, unless you're obsessed with originality. (some are, and that's okay)

[4uall]

found this little tid bit

http://www.familycar.com/Classroom/ignition.htm

[124JOE]

you can sign in photobucket with you facebook id and your good

[majicwrench]

IF the car runs the coil is fine, are you replacing it cause the tach does not work??

[Kent124]

This works well with my 2L engine and closely matches OEM specs: ACCEL 8145 SuperStock Ignition Coils.

FWIW, my tach was jumping around and I ended up installing an ACCEL coil and new control module (under the coil). Tach is rock solid now.

[manoa matt]

I would buy a new control module first, install that and test again. You can get them at any auto parts store for around $25, take your old one and show them. Once the control module is replaced drive around and see what happens. If the coil is failing it may only fail at high RPMs.

The 79-85 distributors are a "breakerless electronic" system. They don't use a typical points coil. The Accel coil Kent posted is a coil that has the closest specs to the original. I've had one on my daily driver for about 5 years now.

[vandor]

. My tach is not working right and that was my first guess.

If that is your only problem then I would not replace the coil. What is the tach doing? Some people have found putting a capacitor between the coil negative terminal and ground fixes a bouncy tach. I can find out the type of capacitor if needed, just PM me.

[deadmeat]

Thanks for the link to the Accel coil. I am looking at replacing it to fix the jumpy tach. The resistance on the original is out of spec. The inline resistor you can add is not supposed to be necessary for 79 and later from what I've read, which is why I'm looking for another answer. I will start with the control module, but since the coil is out of spec, that was my first guess. My grounds are clean, although, I haven't refurbished any of the yet. Hope that answers most of the questions. Thanks to all who offered advice and help.