lifespan for ignition coils

mostsmooth

Active Member
Nov 12, 2002
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we are supposed to replace spark plugs every so often, don't know offhand what that interval is, but let's say it 50k miles. we do this because their performance begins to fade I assume?
so, is the same true for the ignition coil?

also, I attached a pic of the post of my coil. seems really beat up, not sure how that happens? is it just from being 25+ years old and 145k+miles? doesn't seem like just the age would make it look like that, and really, 17 of those 25 years the car wasn't being driven. it couldn't be from arcing inside the boot, could it?

I tried to do a search related to coils to see what's been discussed, but I kept getting a server error, sorry.

thanks
 

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Ignition coils don't have a scheduled interval for replacement. They fail when they fail, and that's when you should replace them.
 
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thanks all,

just so I'm clear on what 'fail' means, there's no grey area? it is either working 100% or 0%?
if that's not the case, is there some type of test that can be performed to check the current operation?

also, for future reference, if ever it does need to get replaced, is a stock ford coil the way to go, or are there better alternatives?

thanks again
 
You can check the resistance of the primary and secondary coils. I do not know the specs for these because if it’s significantly off, the car will also be off or misfiring.
 
thanks all,

just so I'm clear on what 'fail' means, there's no grey area? it is either working 100% or 0%?
if that's not the case, is there some type of test that can be performed to check the current operation?

also, for future reference, if ever it does need to get replaced, is a stock ford coil the way to go, or are there better alternatives?

thanks again

Correct, it either works or doesn't.

Most coils can be tested if you can find the specs, they used to be in the back of the GP Sorensen paper catalog back in my parts counter monkey days, but try finding a store that still carries GP Sorensen and/or still has paper catalogs with all the goodies hidden within.

Stock Ford (Motorcraft) is the way to go until you get into serious modifications.
 
I'll mildly disagree on works-or-doesn't. If it's leaking electrolyte it can just perform poorly. That is very unlikely with a stock coil. Very likely with MSD or equivalent Chinese crap.
Electrolyte is in capacitors. The wire windings need insulation, not a conducting medium.
This style of coil has epoxy, and the can style is oil filled. If the epoxy goes on an MSD Fox coil, it buzzes. (The replacement does not do this.)
 
I have an oem original coil in my car. Still kicking. Looks much better than yours OP however.

I disagree on the works or doesn’t part though. I had an aftermarket accel coil and the car would break up over 3000RPM. I replaced the coil and that problem went away.
 
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thanks all,
seems there are some degrees of 'fail' not just working or not working, but I don't know that I'm going to go through with trying to figure out how to do any special testing.
I thought I saw in a youtube vid some type of thing you just hook up to the coil and see how strong the spark is or something, but if you guys never heard of it, maybe it's car specific or something.

thanks again!
 
Ok most, coil is cheap enough to replace with motorcraft one and shelf the origanal,this way you'll have a working spare.
 
Electrolyte is in capacitors. The wire windings need insulation, not a conducting medium.
This style of coil has epoxy, and the can style is oil filled. If the epoxy goes on an MSD Fox coil, it buzzes. (The replacement does not do this.)
You're correct that's it's not electrolyte, but on subsequent research I was correct that the MSD TFI coil is oil-filled. I didn't think it was my imagination that it leaked a bunch of yellow oily crap out onto the mount and started missing at boost. Short story MSD is crap in shiny red.