Aftermarket Ignition

[edjolly]

Any opinions? My 75 seems to have a weak spark, under load it chugs (not lugs) badly like there is incomplete combustion. There is no miss, and I'm pretty sure the mixture is good. All is stock, and I'm thinking of upgrading--or was stock in those years fairly hot (I'm thinking GM HEI hot) and mine is just tired. The plug color is good, and the problem only manifests at 2000 rpm or less under load, like pulling grades.<br>Was the Ford ignition in those years reliable or is it a priority upgrade, like front discs?<br><br>Ed<br>

 

[Hnrys69]

check your coil

 

[rjlougee]

The stock ignition is anemic at best. A very popular swap is the Duraspark conversion. There are several write-ups on it, check the tech section.<br><br>I'm running a Jacobs System on mine and it's made a significant difference. I was having some driveability problems with mine that I thought were coil related, and pulled the Jacobs. After finding the problem was a bad FPR I reinstalled the Jacobs and was surprised at how much more power it had with it, and got better mileage as well.<br><br>Some of my buddies have the MSD ignitions, but none seem to report the same success.<br>Joe

 

[edjolly]

[quote author=rjlougee link=board=5;threadid=8590;start=0#61307 date=1030775695]
I'm running a Jacobs System on mine and it's made a significant difference. I was having some driveability problems with mine that I thought were coil related, and pulled the Jacobs. After finding the problem was a bad FPR I reinstalled the Jacobs and was surprised at how much more power it had with it, and got better mileage as well.

FPR? I'm guessing you're running the 5.0 EFI?

It's a '75, so I've already got the Duraspark. I guess It's pretty good huh? I will check the coil.
Ed
[/quote]

 

[SteveL]

I'm very happy with the DUI set-up.

 

[brokenhorse]

MSD 6a For me does a wonderful job SO FAR ?:?

 

[Jeepster]

The duraspark is fine......toss the coil for $15

 

[broncoswede61]

I like my Jacobs system,compared to the stock set-up it was a great upgrade...although some people have had problems and hate it.You could also try Petronix -it's pretty cheap....but again there are some negative opinions of it also.

 

[astark]

I just love my MSD ;D

 

[red67]

I ditched the Durasprk on my 351. I am very pleased with MSD 6AL Offroad, Blaster 2 coil, and the pro billet HEI distributor.

 

[Broncobowsher]

Switched to Jacobs box. Big difference in spark. I was ably to lower idle speed a couple hundred RPM and keep the engine running.

 

[76Broncofromhell]

Factory DuraSpark, and it works great.

 

[Jeepster]

[quote author=76Broncofromhell link=board=5;threadid=8590;start=0#62117 date=1031101783]<br>Factory DuraSpark, and it works great.<br>[/quote]<br><br>Really.....why make science when simple works good.

 

[Jerry_Poplin]

I like my Mallory

 

[brewdude]

[quote author=broncoswede61 link=board=5;threadid=8590;start=0#61356 date=1030811358]<br>I like my Jacobs system,compared to the stock set-up it was a great upgrade...although some people have had problems and hate it.You could also try Petronix -it's pretty cheap....but again there are some negative opinions of it also.<br>[/quote]<br><br>I have the petronix, I haven't had any problems, it was cheap and easy to setup.

 

[edjolly]

I checked the coil. It was fine. I cleaned all the contacts and reinstalled. The problem is less severe, but still there. I got some platinum plugs and will put those in this weekend--maybe that will help.<br>I assume the Duraspark unit will either work or not?<br>Also, Napa sold me 7mm plug wires. My HEI on my Blazer takes 8mm--is 7mm ok for the Duraspark?<br>Any other ideas? Hotter coil?<br><br>Thanks,<br><br>Ed<br>

 

[Jeepster]

[quote author=edjolly link=board=5;threadid=8590;start=15#62219 date=1031112305]<br>I checked the coil. It was fine. <br>[/quote]<br><br>How did you check the coil?

 

[edjolly]

[quote author=jeepster ]<br><br>How did you check the coil?<br>

<br><br>I pulled and checked the resistance from the battery terminal to the dec terminal--tolerance is 1-2 ohms.<br>Then I checked the resistance from both the battery terminal and the dec terminal to the high voltage output terminal--tolerance is 12-14 thousand ohms, or it may be 13-14 thousand, I can't remember.<br><br>Ed<br>

 

[75]

i did not trust my old ignition wiring; it was just too brittle and aged looking after having set next to the engine for 30 yrs. thats why i put in a dui. got rid of all the old wiring, really cleaned up the engine area. now i feel more secure gettin in the woods and not breakin down. additionally, the difference in start ups and acceleration are truley amazing. it is said you gain some horse power due to the hotter spark and i buy that. kinda costly, but you will love it.