Pertronix fix for 300 six

[fmfmedic]

This is just for information and a heads up for owners of old 300's with points. Last year my 1972 F250 started running rough. Checked the timing and it was jumping all over the place. Dwell was jumping 32-39 and wouldn't stabilize, even after installing new points. A little measuring determined that the rub blocks on the distributor shaft had uneven wear after 44 years and 166000 miles, so I started looking for a new distributor and guess what? They are not available, period. Not new, not rebuilt, not even used in the wrecking yards. I pulled the points out and put a Pertonix Igniter in. Pertronix doesn't use a rub block and my bushings were good, so I figured it would work.

It did. The old beast purrs like a kitten and has a lot more power. Pertronix is the way to go if you care about staying OEM, and lots less expensive than a new HEI setup.

[sargentrs]

You could have also swapped in a Duraspark electronic ignition set up for less than what you paid for the Pertronix. Just get a distributor and ignition box from a '76+ F100 with the 300 I6 and it'll drop right in. You can get both from RockAuto for around $75 total. Only hard to find/expensive part is the wiring harness. It can be gotten at American Autowire for around $100 or make your own like I did. Just thought I'd drop that in. I put 2 Pertronix in my '64 Fairlane and both burnt up in under a year. Put in the Duraspark and have been happy ever since. Glad you got her purring again!

[colnago]

Not to start a war, but I've been running a Pertronix on my FE for 4+ years with no problems. My only hiccup was when I installed it, and pushed the ring all the way down the distributor shaft. The sensor didn’t pick it up, so it wouldn't spark. Once I raised the ring to be level with the sensor, smooth sailing (well, as smooth as you can get on a fifty-year-old V8 with burnt intake valves),

That being said, I will probably not transfer the Pertronix to the block I'm rebuilding.

Joseph

[colnago]

sargentrs,

Looks like a pretty easy mod for my FE. You mentioned making your own harness. Did you get the plugs from somewhere, or did you just use individual spade-style connectors from an auto parts store?

Joseph

[sargentrs]

I bought Dorman connectors from Rockauto. It'll take me some searching to get the part numbers but they were about $10 each. On my truck, I got a distributor harness from a member but just used spade terminals for the power circuit. I would recommend using a relay and triggering it from the stock ignition harness. This will allow you to leave your original wiring intact in case you ever want to go back.

[sargentrs]

Not to start a war, but I've been running a Pertronix on my FE for 4+ years with no problems.

No offense taken! I did a lot of research and heard the same comments. Some people have no problems some people do. I was just one of the ones who did.

[sargentrs]

Here's the 2 connectors I bought. https://www.rockauto.com/en/moreinfo.ph ... 4694&jsn=1 and https://www.rockauto.com/en/moreinfo.ph ... 4694&jsn=2 Can't remember which one, 3 prong or 4 prong, but the locking ears were not in the proper location to match up to the distributor so I just shaved the tabs down until it stuck in there good enough and threw some tape around it for security. On the 3 prong, it has 4 wires but one of them is used for a tach so I just wired it together with the other prong. For the 2 prong at the ignition box, I bought an additional 3 prong and just used 2 of the wires. The sockets fit the same for both 2 prong and 3 prong.

[colnago]

I would recommend using a relay and triggering it from the stock ignition harness. This will allow you to leave your original wiring intact in case you ever want to go back.

A relay? Isn't it all 12VDC? What am I missing? Current draw from somewhere?

Joseph

[sargentrs]

Your original ignition wiring runs through the pink resistor wire and only provides about 9v in run mode to the distributor to avoid burning up the contact points. For the Duraspark you need a full 12v to the distributor. You can bypass the pink resistor wire at the ignition switch for your power source (as most of the Duraspark conversion diagrams show) but if you use a relay, using the original harness connection in the engine compartment as the trigger source, you don't have to mess with any of that and can leave your original wiring intact. Much cleaner installation and you're guaranteed a consistent 12v source to the distributor and coil.

[colnago]

Got it! I actually had to bypass the ballast resistor for the Pertronix installation. I've seen some Duraspark diagrams that use the ballast resistor, and others that don't. I figure I'm okay with a bypass, as long as I label it, and the coil (I think it's the coil) can take a constant 12V, which I think the Duraspark coils can. Correct me if I'm wrong here, though! Coils are actually pretty cheap from Rock Auto!

Joseph

[sargentrs]

That is correct. I like to get everything for a particular vehicle at the same time. For a small block truck, I use a '77 F100 with a 302 and order the distributor, ignition box and coil at the same time. Rockauto is my favorite place to do this. For my Fairlane I chose a '78 Mustang II with a 302 for my selection and bought the same parts. That way you're pretty sure you configuration will work well together.

[colnago]

What do I select for distributor compatibility with an FE? I read in one spot that a 302/351/400/460 are compatible, and in a lot of places that they're not. Any hints?

Joseph

[ThinLizzy13]

Dunno if you want one now that you have pertronix, but RockAuto carries the original style distributor...

[colnago]

From this thread, I was thinking about going with a Duraspark system for my rebuild (352, bored 0.030 over). I thought the 390 went further than '76, though. Since it didn't, what are people using for a Duraspark distributor in their FEs? As sargentrs suggested, I'm trying to get everything for a single engine, rather than try to mix 'n match.

Joseph

[ThinLizzy13]

For the 352 in my '67 I bought a dizzy for a '76 360.