HOT coil
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Elder User
Joined: Feb 2005
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From: in country near Boone, IA
HOT coil
Has anyone had a coil get so hot that they could not touch it even just for a split second without getting severe burns? The coil on my 400 with Edelbrock Performer manifold gets so hot you can not touch it after the engine is at operating temp. I've been having erratic ignition trouble when the engine is up to operating temp and i'm starting to think it's the coil saying "I've had enough - it's too damn hot in here" lol. Anyone have this problem? The coil is an Accel 40,000v coil with the OEM type terminals on the top of it, and i think it's oil filled. It's mounted in the stock bracket and I believe it's soaking up heat from the excessively hot intake manifold (another concern and thread on here already). Any suggestions / advice?
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Joined: Nov 2007
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From: Denver Metro Area, CO
If there were that much excess heat to be soaked up by surrounding components, I'd think they'd ALL be hot.
If it were mine, I'd be suspicious of the ignition wiring - does the coil need 7V or 12V (for example) and what is it getting....
If it were mine, I'd be suspicious of the ignition wiring - does the coil need 7V or 12V (for example) and what is it getting....
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Elder User
Joined: Feb 2005
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From: in country near Boone, IA
ctu- well pretty much everything under the hood is hotter than I think it should be. INtake temp is 200-230 deg., 190 degree thermostat and guage reads in lower portion of NORMAL range, radiotor is ~190-200 degrees on the upper water tank. The lower distributor base (aluminum part) gets so hot it will also burn you. I know it's not a fair comparison, but the aluminum based dizzy in my '96 ford truck runs much cooler (you can actually hold your hand on it for several minutes). I have ceramic coated headers but do they still increase underhood temps for all components? Think ignition wiring is OK as i've inspected every inch of it (literally) when I rebuilt this truck. Battery is staying charged after sitting idle for the past two weeks.
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Joined: Nov 2007
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From: Denver Metro Area, CO
I have the Performer 400 EGR intake manifold on my 1981 F350, I mounted my coil on the left head:
I also have an Edelbrock #8725 wood spacer between the manifold & carb to keep the fuel from getting too hot in the bowls:
Edelbrock 8725 - Edelbrock Carburetor Spacers - Overview - SummitRacing.com
I don't know what the temps are of the other devices you listed but have never encountered the situation you describe (or noticed it) nor have I tried to touch the things you listed.
I'd be hard-pressed to trust a factory temperature gauge, I can say that much.
I'm still suspicious of the ignition/wiring/coil, though.... Even though the wiring itself may be OK, is the correct voltage being sent to that device (the coil)....
I also have an Edelbrock #8725 wood spacer between the manifold & carb to keep the fuel from getting too hot in the bowls:
Edelbrock 8725 - Edelbrock Carburetor Spacers - Overview - SummitRacing.com
I don't know what the temps are of the other devices you listed but have never encountered the situation you describe (or noticed it) nor have I tried to touch the things you listed.
I'd be hard-pressed to trust a factory temperature gauge, I can say that much.
I'm still suspicious of the ignition/wiring/coil, though.... Even though the wiring itself may be OK, is the correct voltage being sent to that device (the coil)....
MSEE
Joined: Apr 2004
Posts: 10,386
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From: Austin, TX
If your coil is getting THAT hot, it's possible that it's pulling too much current. Either you're feeding it too high of a primary voltage, or the primary winding resistance is too low.
What kind of ignition system are you running? Has anything been modified or mixed and matched?
What kind of ignition system are you running? Has anything been modified or mixed and matched?
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Elder User
Joined: Feb 2005
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From: in country near Boone, IA
fmc400 - I have an Accel coil, #140207. It's rated at 45,000Volts @ 1.4 ohms. I have 1.4 ohms resistance across the primary contacts (this is when it's cold - did not check when hot). When I checked voltage to the coil, Key on, engine off, there are 6.7 volts to the coil. The distributor is a stock DSII and everything looks fine in there. All ignition wiring is stock and everything appears to be in excellent condition visually. Also a new Motorcraft ignition module.
I'm almost certain the coil is heating up from the radiant heat from the manifold. The manifold gets unbelievably HOT. Is it possible that the water passages in the manifold are somewhat plugged and the water is not cooling the manifold?? It was a brand new Edelbrock Performer manifold when installed.
I'm almost certain the coil is heating up from the radiant heat from the manifold. The manifold gets unbelievably HOT. Is it possible that the water passages in the manifold are somewhat plugged and the water is not cooling the manifold?? It was a brand new Edelbrock Performer manifold when installed.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
You've done a very thorough check of the coil primary circuit, and everything seems right on the money. At this point, your original hypothesis sounds more like the culprit; how it's happening, however, might be harder to diagnose. Can you try relocating the coil?
As a side note, a 400 has a dry intake, so no water passages going through it.
As a side note, a 400 has a dry intake, so no water passages going through it.
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