A few have also posted up to use stand-offs of one type or another, to get more air flow behind it.

Paul

 

Oddly enough, my OEM was still good until the day it acted up May 30, 2016 as I headed home a hot afternoon. Luckily I had a cold soft drink and dousing it got me going a couple miles more, where I pulled into a P-lot to put my spare in.. It was uncanny, was the very same week a co-worker at Advance asked if I still had the original in my truck, and I did plus a spare behind the seat (it had spilled it's potting into the box, but it worked .... it's back in storage, thinking will refill with J B Weld.). My original had spilled it's potting onto the fender apron maybe years earlier.

 

Yes, I’ve got mine moved back on the fender away from the heat and spaced away from the fender with a stack of washers. May duct some cool air to it as you have. My spare module is equally Chinese, but at least it’s older, better quality NAPA Chinese.

The ballast resistor gets far hotter than the ignition module, and that worries me. Any experience or advice?

Thanks gentlemen

 

Anytime you have resistance in a wire sufficient to cause a voltage drop, you'll have heat. A ballast resistor is normally very hot in operation. I would not be surprised if one runs 200 or more degrees, and even 300+ especially if the key is left turned on and the engine not started. They use ceramic blocks as bases due to heat. They definitely live hotter than a ICM could live with. If you have a poor electrical connection, it has high resistance and it will get hot, a ballast resistor is designed to act the same. A resistance wire circuit does too, but it is intended to do so over a longer run, not as concentrated in one point, so it'll be cooler.

 

Thanks for explaining that.

 

Believe it or not, the OE location for the modules is generally one of the coolest areas under the hood.
I did heat tests on my trucks with thermometers in various places while I ran the vehicle around.
I had noticed that FORD put most of their modules on the driver side rear, or mid to rear, of the engine compartment. When I upgraded to Dura Spark on my Early Bronco, I did all that testing and found it to be one of two cool areas.
The other being on the leading edge of the driver’s wheel well. Which, of course, the full-size trucks don’t have, but the Early Broncos have distinct wheel houses.

What are you doing with a ballast resistor by the way? Total rewire?
Normally Ford uses a resistor wire instead. Just curious. Maybe it was mentioned already?
What I do with most rewires is using ignition components that no longer need resistors. That way, I don’t have to deal with the heat of a ballast.
Finding a safe location away from things that can melt isn’t too bad on one of our trucks, but on other vehicles, it could be a nightmare finding a spot that won’t be damaged.

 

Thank You. Interesting .... I thought it might be a hotter spot with that exhaust manifold so near but maybe air just flows better there?

 

The fan wash can be pretty powerful sometimes. And with the rear actually being open too, on the Early Broncos, there is some actual flow-through as well.
Not sure how it's accomplished on the big trucks, since the module is kind of cornered there by the hood hinge, wire bundles (on some trucks like mine at least) and firewall. Looks like, along with it being in line with the exhaust manifold (though not right next to it) it would be kind of outside the normal air-flow area.
But apparently not...

Paul

 

I have had only one vehicle with a Duraspark ignition. And that is what I installed on my '71 F250.

Very often I read about very hot Duraspark modules. I believe those stories because why would anyone lie?

My experience is very different.

A couple years ago I installed a Duraspark ignition on a '71 F250. The engine is a '98 5.0. I used Painless wiring harness 30812, and all of the components (distributor, ignition coil, ignition module) are for '85 Mustang 5.0/302 carb/stick.

I completely bypassed the factory pinkish wire resistor (resistance value for breaker points) and integrated the white ceramic ballast resistor included with the Painless wiring harness. After installation, I followed the instructions of the Ford Duraspark troubleshooting guide and measured the power at the ignition coil. It measures 7.3 V which is exactly what the manual says it's supposed to read.

It's been over 7k miles without any trouble. After driving several miles and the engine running at operating temperature, the heat measurements were taken by touch and are as follows:

The white ceramic ballast resistor is only slightly warmer than ambient temperature. The ignition module (newer production Motorcraft DY893) feels exactly ambient temperature. The ignition coil (mounted on inner fender) is quite warm to the touch. But I have no problem grabbing onto it firmly with my bare hand, and could probably hold it all day long.

I'm guessing my module runs cool because it is newer production, and may have different electronics in it than an older factory module.

 

I initially thought to remount in another place, but after considering all, it evolved into just mounting open side up in a good air flow. The idea of a added hose or tube to the core support might work against cooling it by blocking fan wash. I'm beginning to think just getting the open side up so potting stays in, and maybe moving it forward on the fender by that 10 or so inches might be "the deal". Easy job of wire extensions, solder, etc. too.

I have some pieces that would be good 90 degree angle to bolt secure to the apron, and let me mount the thing open upwards, and still cover the open side, and make a decent heat sink while funneling or channeling that fan wash, plus gets it out of that back corner, I don't carry a under hood jack, mine was already broke when I bought the truck.

The OEM one had puked it's potting, but kept working for a good bit afterwards. My current one is a replacement from 2016, it's not puked yet. Might leave as is and just keep spares on board, they are easy change outs.

crude illustration I know ..............

 

When I converted my '71 Bronco to Dura Spark, I spent a week or so measuring the under-hood temps in different areas during my daily 45 minute commute.
The two most reasonable spots, with the lowest temps were, on the driver's side wheel well top, and the driver's side wheel well front. I ended up moving my washer reservoir to the firewall and mounted my ignition module to the leading edge of the wheel well.
When I experienced early failures of the $20 Kragen cheap replacements, I ended up buying a Ford Motorsport/Racing module built by MSD. Lasted for about 10 years and 80k miles or so, and as far as I know is still good just waiting for me to drive it again.

Replaced the one on my '79 with an ACCEL 300+ module running off the stock distributor.

Paul