Rotor with two contact points??

[Wishmeluck]

I started pulling apart a 351w out of an 82 Bronco to rebuild and when I pulled off the distributor cap I noticed the rotor looks veeeeery different from any other I've seen (image below).
Anyone have any input on what's up with this dual Contact rotor?

 

[johnnyreb]

I started pulling apart a 351w out of an 82 Bronco to rebuild and when I pulled off the distributor cap I noticed the rotor looks veeeeery different from any other I've seen (image below).
Anyone have any input on what's up with this dual Contact rotor?

I saw one like it on Green sales like it today. Maybe they could help you. If you have any part numbers on it.

 

[Tiha]

Can't say I have seen one in person either. Looking on Rock auto it lists that rotor for engines with electronic controls.

They also show a normal looking rotor so must have been near when they changed over.

 

[johnnyreb]

Can't say I have seen one in person either. Looking on Rock auto it lists that rotor for engines with electronic controls.

They also show a normal looking rotor so must have been near when they changed over.

I ,d say it was made like that. For when it got a certain speed. It would run on certain cylinder to save on gas.

 

[Tiha]

I ,d say it was made like that. For when it got a certain speed. It would run on certain cylinder to save on gas.

I am sure the engineers and probably someone here knows why it was like that.

I was kind of thinking it was for emissions. Like an attempt to reduce emissions by burning in the exhaust ****** of the cylinders. But I could be thinking of some completely different vehicle.

 

[johnnyreb]

I am sure the engineers and probably someone here knows why it was like that.

I was kind of thinking it was for emissions. Like an attempt to reduce emissions by burning in the exhaust ****** of the cylinders. But I could be thinking of some completely different vehicle.

I remember reading one time. Where it --this motor---I think it was in the 80,s----and they were talking about a 8 or 10 cylinder worked off of a car back in the 30,s--a LaSal or something. They had it figured out when 4 or 5 cylinder ---worked like a regular v-8---but at a certain speed --say 40 mph ---4 cylinder would kick out and only 4 cylinders would be working. It was to save gas and I guess they had a way for 4 cylinders would stop getting gas.-Does that make sence?

 

[Wishmeluck]

So heres what Ive found out so far...apparently this distributor setup was used on certain 81-83 ford vehicles that had EEC III. One type was for carboreted models and the other type (this one) was used on vehicles that had Ford's central throttle-body fuel injection system. I know Chevy had TBI, but cant recall ever hearing about Ford vehicles having it. Anyone else have any input on this??

 

[willdy]

I started pulling apart a 351w out of an 82 Bronco to rebuild and when I pulled off the distributor cap I noticed the rotor looks veeeeery different from any other I've seen (image below).
Anyone have any input on what's up with this dual Contact rotor?

I had this in my '81 carburated 351w. The spark fires alternatively from one contact to the other. If you follow the plug lines, you'll see the firing order seems wrong because of this. I discovered it when replacing the distributor with an HEI style and had to look up the firing order since the cables were going to the wrong cylinders. BTW -the HEI really woke up what seemed to be a tired motor. Very easy starts now in all weather and dramatic power response improvement.

 

[L\Bronco]

I remember reading one time. Where it --this motor---I think it was in the 80,s----and they were talking about a 8 or 10 cylinder worked off of a car back in the 30,s--a LaSal or something. They had it figured out when 4 or 5 cylinder ---worked like a regular v-8---but at a certain speed --say 40 mph ---4 cylinder would kick out and only 4 cylinders would be working. It was to save gas and I guess they had a way for 4 cylinders would stop getting gas.-Does that make sence?

Caddy did that one in the 70's, they called it the 4-6-8, It didn't work well at all (too soon they needed technology to catch up)

 

[L\Bronco]

So heres what Ive found out so far...apparently this distributor setup was used on certain 81-83 ford vehicles that had EEC III. One type was for carboreted models and the other type (this one) was used on vehicles that had Ford's central throttle-body fuel injection system. I know Chevy had TBI, but cant recall ever hearing about Ford vehicles having it. Anyone else have any input on this??

Ford used TBI on a few, plus a couple feedback carb systems as well. Lincoln Mark, T-bird 5L, Mustang 3.8L, F150, 5&5.8L ect...
Some of them used an early attempt at "distrbutorless" ignition, They still had a distributor, but all it has in there is a shaft and a rotor, no pickup or advance mechanisms. The earliest I saw was a 79 Lincoln Town car with TBI and that distributor. Most of them got replaced with carbs and duraspark3 up here.
I believe that's what you have there. I've never had one apart and I haven't seen a live one in 30 yrs.
I see there is no center electrode to connect to the coil tower, could you post a pict of the cap and wires?
Just curious now.
Cheers

 

[L\Bronco]

Caddy did that one in the 70's, they called it the 4-6-8, It didn't work well at all (too soon they needed technology to catch up)

My bad, It was 1981
Sorry

 

[johnnyreb]

Caddy did that one in the 70's, they called it the 4-6-8, It didn't work well at all (too soon they needed technology to catch up)

I saw a International v-8 work off of 4 cylinders. The parts guy sold was the wrong gasket. We got it together and it started and ran smooth, We couldn,t figure out how it was firing through all the plug wires. and not the plugs-----then we figured out it wasn,t getting compression and figured they sold us the wrong gasket--tore it back down and sure enough. Hear they guy sold us a gasket for a 4 cylinder motor. Eventhough we told him the sizeI think it was a 395--4"-been 40 years.

 

[Wishmeluck]

Here's the cap and wires.

Also a different angle of the rotor. There is a small metal electrode in the center, but talk about tiny.

 

[L\Bronco]

Here's the cap and wires.

Also a different angle of the rotor. There is a small metal electrode in the center, but talk about tiny.

Thanks for the picts Wishmeluck.
If I am correct here, your windsor has a sensor on the timing cover kind of behind the balancer and 4 reluctor pegs on the back of the balancer with no electronics in the distributor.
If so, this is fords early attempt at waste spark. They fire both running mates at the same time, the one on compression fires and the one on exhaust does nothing. (wasted) this eliminates the need to sync to the cam like the pip sensor does in the regular distributor. All of the timing advance is handled by the EEC3 module and the ign module. It was horribly over complicated and un reliable. (another example of the manufacturers being a little ahead of their time.) Still pretty cool though.
Cheers

 

[Wishmeluck]

Huh, thank L! And yes, you're spot on with the sensor and balancer.

My plan is to go through this 351 and swap it into my bronco with a 302. The po already did away with emmisions and converted everything to DS2 so that's one less thing. But still, I can't believe what a snake pit the engine compartment looks like with all the emmisions stuff on my donor rig. Talk about a MESS!! No wonder people want to get rid of all their early emmisions stuff.

 

[L\Bronco]

Wildly is correct, in studying it closer, it doesn't simulate waste spark, it just alternates between the 2 sets of conductors in the rotor, like he said. Which totally explains the weird wire placement.
I can't for the life of me figure out why they would do this rather than run a standard cap and rotor though. It makes no sense to me. They might be trying to control arc-over between cylinders. (I believe they started using a higher voltage coil on these.)
Oh well, sorry for the mis-information.
Cheers

 

[L\Bronco]

Huh, thank L! And yes, you're spot on with the sensor and balancer.

My plan is to go through this 351 and swap it into my bronco with a 302. The po already did away with emmisions and converted everything to DS2 so that's one less thing. But still, I can't believe what a snake pit the engine compartment looks like with all the emmisions stuff on my donor rig. Talk about a MESS!! No wonder people want to get rid of all their early emmisions stuff.

Nice, That one has the VV carb, Please tell me that is going away too! I rebuilt my share of those when I was on the bench (The engineer that did that one should be shot with a ball of his own sh-t!!)

 

[L\Bronco]

Huh, thank L! And yes, you're spot on with the sensor and balancer.

My plan is to go through this 351 and swap it into my bronco with a 302. The po already did away with emmisions and converted everything to DS2 so that's one less thing. But still, I can't believe what a snake pit the engine compartment looks like with all the emmisions stuff on my donor rig. Talk about a MESS!! No wonder people want to get rid of all their early emmisions stuff.

I'M going the other way with mine.