383 dual point dist

[bluefury361]

I was trying to figure out why the new dist cap I got from halifaxhops at Carlisle last July wouldn't fit my 67 383. I removed the rotor and took a good look at the dist.... Then had a "WTF" moment. My car has a dual point dist in it. I did not realize that until today.
The shop manual does not cover a dual point in the 383 and no points part numbers in the parts book.
Does anybody recognize this. I need points for it. And apparently the caps are different, need one of those too. I'm not ready to pull it out and look for numbers yet, that time is coming.

 

[detmatt]

@halifaxhops

 

[cbarge]

Must be either an early B (361,383) or aftermarket dizzy.
Typically cast iron housing and made by Prestolite.
They do take their own rotor and cap which as you found out does not interchange with the Chrysler dizzy.
Canadian built cars got Prestolite dizzy's right up until 1967--single or dual point,LOL!!

 

[PH27L7]

To my knowledge all mopar big blocks with Prestolite dual points uses the same contacts. You can find out exactly what distributor that is if it still has the aluminum tag under one of the clip mounting screws. It should have a 7 digit mopar # as well as the Prestolite number which starts with IBS-. They used Prestolites in various HP mopars until the early 1970's. For some reason (probably $) some HP motors / years had them and some didn't, also depended on trans.

That distributor is pretty crusty, might want to disassemble & lube / clean up.

 

[413]

Yes it has brown rust haze on everything inside. Maybe it’s not rust. Needs serviced, maybe mail it to the distributor guy halifafhops

those are to be lubed in the little cap on the side every 2000 miles, according to the FSM. And the point cam and under the rotor every 10,000 miles. Anybody ever do that?

it looks like a stock prestolite.

 

[bluefury361]

Yes it has brown rust haze on everything inside. Needs serviced, maybe mail it to the distributor guy halifafhops

it looks like a stock prestolite.

I'm going to get his input and perhaps send it to him to rebuild.

 

[Snotty]

I've never understood the purpose of dual points.

At at motorcycle shop once, when I was in my teens, I saw a guy tuning a Japanese bike: triple points!!! Whoa!!

But, why?

 

[PH27L7]

I've never understood the purpose of dual points.

At at motorcycle shop once, when I was in my teens, I saw a guy tuning a Japanese bike: triple points!!! Whoa!!

But, why?

Dual points allow the dwell to be increased, gives coil more time to charge. An old time way to increase high RPM hot spark capability. The bike triple points is a little bit of a head scratcher, my best guess would be 3 separate point circuits with 3 coils for use on a triple.

 

[furious70]

Does it have the tag? It's likely worth yanking to sell and buy a reman for yourself. RB ones are wortj a lot more but they are still valuable

 

[halifaxhops]

They definitely made them in the USA, Usually police packages. The points and cond are the same for all the big block dual points small block are a mirror image. Dual point caps are different they have a small tab on the cap that lock into the hold down, not a tab on the vac advance to the cap. That definitely looks like it was a long time since it was serviced. I would pull it and disassemble it and clean it the best you can. The oil cup on them is important to lube it keeps the shaft oiled, one of the reasons they have a higher bushing failure, never lubed. Hope it helps.

 

[Big_John]

FWIW, I rebuilt a Prestolite dual point. Pretty easy, including pressing in new bushings. The bushings are standard size Oilite bronze. I even found a new oil cup on eBay. Mancini (and probably others) have the vacuum advance. I converted to pointless electronic with a Pertronix ignition.

A video... His voice can put you to sleep, but it's good content.

 

[mr. fix it]

Dual points allow the dwell to be increased, gives coil more time to charge. An old time way to increase high RPM hot spark capability. The bike triple points is a little bit of a head scratcher, my best guess would be 3 separate point circuits with 3 coils for use on a triple.

Also understood that this was for high RPM situations where it was important to decrease point's bounce causing ignition break down & mis-firing.

The triple point setup on the bike was for the Kawwy' triple 400cc 2 stroke engine developed for the racing bikes then spilled over onto the street bike versions for a few years back in the 70's & early eighties before electronic ignition.
Screaming demons happiest at 7,000+ rpm's.This is where my Honda redlined...
Extremely difficult to setup and keep setup. Likely saved a few lives since the bike was in the garage more than the street LOL!

 

[PH27L7]

Also understood that this was for high RPM situations where it was important to decrease point's bounce causing ignition break down & mis-firing.

The triple point setup on the bike was for the Kawwy' triple 400cc 2 stroke engine developed for the racing bikes then spilled over onto the street bike versions for a few years back in the 70's & early eighties before electronic ignition.
Screaming demons happiest at 7,000+ rpm's.This is where my Honda redlined...
Extremely difficult to setup and keep setup. Likely saved a few lives since the bike was in the garage more than the street LOL!

Since point bounce would be a function of the contact spring tension & cam lobe ramp I would doubt that a single or dual point would have any advantage in that department. Some aftermarket point sets have really bad spring tension (too little or too much) so you have to be careful with what you use.

Interesting about the Kawis, I always lusted after those in the 70's but couldn't afford. They sounded wild & had crazy green paint jobs with a swoopy rear fender.

 

[CBODY67]

One KEY thing is that, at least in the later '60s when they were OEM on the HP dual-point distributor engines (as 440 6nnl and some 4-speed 383 Super Bee/Road Runner cars), the normal Chrysler distributor was ALUMINUM-bodied, the dual point models were CAST IRON-bodied. The distributor caps are unique to each one, as are the rotors, by observation. The cast iron/dual point units probably also have the outer, capped tube for bushing oil additions, too. The aluminum case single point units do not, with the OEM number stamped into a boss on their outer side.

AND, they all go into the same place, within the B/RB engine family. B models being a different length than the RB models. Mopar Perf used to have an adapter to put a RB distributor into a B engine, as the RB model's shaft is longer.

If there's a tag still on the outer case, see what the number is so you can know what the OEM application was.

Enjoy!
CBODY67

 

[PH27L7]

FWIW, I rebuilt a Prestolite dual point. Pretty easy, including pressing in new bushings. The bushings are standard size Oilite bronze. I even found a new oil cup on eBay. Mancini (and probably others) have the vacuum advance. I converted to pointless electronic with a Pertronix ignition.

I also rebuilt one recently, original 1965 383HP, not hard. My intent was to use it to trigger a CD multispark box but that was a fail. Kept on getting random misfires. After much frustration I found out that the distributor phasing was out of whack. I tried everything to make it work, switched from either point set, messed with gap, etc. Other than modifying the distributor (wasn't going to do), it was hopeless. Ended up going with an old Mopar Performance electronic for the trigger, fixed the problem.

Since the original poster's distributor is not original, I would just go with a cheap rebuilt single point or electronic. Might actually make some money selling the dual point.

 

[Quantum53]

Old school? I always ran dual points when I could. Big or small block. I now have a '69 Dart GT, 318. The P.O., installed electronic ignition. I had some problems and went back to original, well almost. It has a '56 Dodge, 315 hemi dual point in it now. All early small v8's will interchange.

 

[PH27L7]

The cast iron/dual point units probably also have the outer, capped tube for bushing oil additions, too. The aluminum case single point units do not, with the OEM number stamped into a boss on their outer side.

Have seen a few cases where the OEM aluminum cases have an external oiler similar to the prestolites. Definitely the exception to the rule though.

 

[Big_John]

I also rebuilt one recently, original 1965 383HP, not hard. My intent was to use it to trigger a CD multispark box but that was a fail. Kept on getting random misfires. After much frustration I found out that the distributor phasing was out of whack. I tried everything to make it work, switched from either point set, messed with gap, etc. Other than modifying the distributor (wasn't going to do), it was hopeless. Ended up going with an old Mopar Performance electronic for the trigger, fixed the problem.

Since the original poster's distributor is not original, I would just go with a cheap rebuilt single point or electronic. Might actually make some money selling the dual point.

No modification needed with the Pertronix. Bolt in.

 

[mr. fix it]

Since point bounce would be a function of the contact spring tension & cam lobe ramp I would doubt that a single or dual point would have any advantage in that department. Some aftermarket point sets have really bad spring tension (too little or too much) so you have to be careful with what you use.

Interesting about the Kawis, I always lusted after those in the 70's but couldn't afford. They sounded wild & had crazy green paint jobs with a swoopy rear fender.

And most careless riders were short lived...

 

[James Romano]

Dual point was a performance add-on and simply extended the dwell

No modification needed with the Pertronix. Bolt in.

Nice job cleaning it up! I should have done the same with mine.
Question.. does your rotor kinda float, meaning it's on, but easy to remove? My setup is exactly the same as yours in the collar height vs the module. I just feel the rotor is not secure with. I was thinking of grinding it, but taking measurements, it's only 1/32" from bottoming out anyway.