When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I am doing a TMeyer 400 build for my 81 F250. I'm going to be putting the Duraspark dizzy back in and praying it works as it was factory tuned for the 351 displacement. I've seen some discussion on aftermarket options, and have had Accel recommended to me by my step father who put one in an 81 F150 302 4X4 (my first truck). I was looking to get everyone here's input and ideas. I am NOT interested in HEI (Chevy style) distributors. I want to keep it similar to stock.
Many aftermarket distributors tout their better, or "full length", bearings. But on a Ford the bottom of a distributor's shaft runs in a bearing in the block that has its own oiling passage. And my testing shows there to be very little side play on even well worn distributors. So I don't see that as a big issue. Given that I'm going with a cheap "new" one I picked up off Amazon.
But, I will put high a quality cap, rotor, and adaptor on it. And, I'll spend time modifying the advance to get what the engine needs as the dizzy I got has an emissions-style curve built in. And, I will run a Ford DS-II ignition box, but will probably run a hotter coil than stock.
I was looking around on Summit and found a Davis Unified Ignition Duraspark dizzy and coil/module set. Anyone have any experience with these?
Save yourself the money and buy a $25 Dodge ignition module and a cheap aftermarket coil, IF that is the way you want to go.
Just went through this last week with Piston Honda in his Newbie Resto thread.
There's $50 worth of parts with an extra $150 worth of stickers on them.
I will run a Ford DS-II ignition box, but will probably run a hotter coil than stock.
"hotter" as in more output voltage?
This is simply a matter of winding ratios and primary voltage.
ANY coil will only build enough voltage to jump the spark plug gap.
Yep. Haven't found the #'s in either the shop manual or the EVTM. I do have two of them on the shelf and both measure exactly the same depending on which DVM I use. One gives 1.1 ohm, another gives 1.2, and the third gives 1.7 ohm. And all of that is taking into account the reading given with the leads touched together subtracted from the reading for the coils.
Oops - You beat me back. Sounds like my coils are right in the middle. Ok, thanks.
...And, I will run a Ford DS-II ignition box, but will probably run a hotter coil than stock.
Originally Posted by Gary Lewis
...Hotter as in a higher ratio. Haven't settled on one, but one of the E-coils was suggested.
Allow me to save you some time and money, Gary. When I first did my own Duraspark II conversion from the stock TFI ignition, I used the stock Ford E-coil and it fried not one but TWO ignition modules. The first one was aftermarket module and it lasted about an hour. The second was a genuine Motorcraft unit and it lasted a few days. I finally bought the correct Duraspark oil-filled coil [and another Duraspark II module] and I haven't fried an ignition module in eight years.
Thanks. But that would suggest the only coil that will keep from frying the module is the original coil. However, as long as you keep the resistance of the primary within the capability of the module it isn't going to cause the module any problems. So, going with one that has the same primary resistance but a much larger number of secondary windings will give higher secondary voltage w/o causing more current to the module.
Yes, Jim will jump in and say that the greater transfer ratio will cause more inrush current and he's right, but that is just a quick burst of power that doesn't generate much heat, and the heat is the killer for the module. So, if you keep the inrush within reason you can go with a hotter coil w/o frying the module.