Dual point distributor

[reborn55]

Wife's coupe has dual point distributor in it, I came to find out.  Does it need to have the resistor block in the circuit to function properly.  right now the resistor is being bypassed.  Car runs good, but afraid I mght burn the points up.  Will probably upgrade to electronic later on down the road.  Any one had any experience with the Accel point replacement setup--Little less expensive than the Pertronix.  
Thanks

[WZ JUNK]

I would think that it would need a by pass resistor but I can not say for sure.  I know the one that I removed recently had a by pass resistor.

I have an opinion based on my experience with dual point distributors.

I would remove the whole unit and replace it.  You are flirting with ancient technology that did not work well even in its time.  Replacing the points with the electronics gadget is okay but it is like putting a new clutch in a car that the tires are falling off.  Today you can buy a complete HEI distributor cheap and give the old dual point the heave ho.  Take it to a swap meet and let somebody else have your problem.

John

[reborn55]

agree with that, but will have to do for now.  Other things are more pressing on the car.  Will wire the way the old Chevies used to be and go from there.
thanks

[enjenjo]

Check to be sure there is not a resistance wire in the harness.

[38HAULR]

Simple check for ballast wire is to measure the volts at the coil with points closed.
Trying by memory here .If higher than  around 7 or 8volts you can bet that there is no  inbuilt ballast or resistance in the feed wire.
Next is the coil,it should be stamped on it,s base "use with ballast" or will have 8v.
If just marked 12v then it is designed for a non ballast system.
Frank.

[reborn55]

Coil says to use external resistor--is stuck up under dash and a little hard to get to.  Wiring is marked for starter wire, hot wire and resistor to coil.  Wired it like that and started and ran goo.  After I rebuild carb will remount the coil, wire it and take for a drive.  thanks

[cr55]

Ken, I had a dual point in mine when I first got it running. Used it about a month and replaced it with an HEI, best thing I ever did...I remember going into a major autoparts store and asking for points! The guy kept looking at them for a long time, then he asked me...Are these points?........Too much aggravation!! Ran way better with the HEI anyway..Go to the junk yard, I'll bet they're really cheap!..CR

[reborn55]

Got 2 HEI on the shelf--but they are the big ones and there is not enough firewall clearance for the big ones.  I eventually will replace either the distribut0r itself or go with Pertronix(have in my 55 and does real well) or Accel unit.  Got a couple of swap meets coming up--will see what is there among the vendors.  
I don't mind points--fun to mess with young guns at the auto supply.

[Mr Cool]

Theres nothing wrong with twin point dizzys, I used one on the race car (my racing rules stated that I had to use what was fitted from the factory) and NEVER had a problem with it, even at the 7500rpm rev limit also set by the rules.
If you set them up properly, and stagger the operation of the points so one set controls the opening and the other controls the closing (like theyre supposed to) then they work very well.
Too many people set them up so both sets of points work in direct parallel, which achieves nothing, and actually adds to the problems.

[cr55]

Theres nothing wrong with twin point dizzys, I used one on the race car (my racing rules stated that I had to use what was fitted from the factory) and NEVER had a problem with it, even at the 7500rpm rev limit also set by the rules.
If you set them up properly, and stagger the operation of the points so one set controls the opening and the other controls the closing (like theyre supposed to) then they work very well.
Too many people set them up so both sets of points work in direct parallel, which achieves nothing, and actually adds to the problems.

I'm not sure what you mean, can you explain? I've never heard of this before...thanks,  cr

[Mr Cool]

Well heres the basics. Its been a couple of years now since Ive had to do it, so Im only going by memory on the numbers.
Points should be open for around 35 degrees dwell angle, to achieve this with dual point you set the 1st points to open earlier than the 2nd, only when the 2nd opens does the coil collapse and the ign cycle is started, then 1st closes before 2nd does, at 35 deg after 2nd has opened. Then of course the 2nd closes shortly after that.
From memory the point gap on a V8 should be about 22thou instead of the usual 18.
The points are less likely to "bounce" and more accurate timing is possible as you dont alter both open and closing when setting up the timing angle.
Does that make sense?
Its not the easiest thing to explain, but I hope you can figure it out.

[38HAULR]

Just an observation.
My understanding was that dual point set ups were initiated for high performance applications to help overcome point bounce at high RPM.
Today we have electronic systems ,either that simply eliminate mechanical  points in a conventional system ,such as the Pertronix conversion.  Or full electronic HEI which is another improvement giving higher spark voltage.
Both systems will leave you with a timing "set and forget" situation as you do not have the issue of points pitting./ mechanical gap/ dwell change.
Unless you are nostalgic ,going dual points today would be akin to searching for a generator to fit a small block Chev or Ford.
Frank.

[chimp koose]

My old accel dual point needed the dwell on the first points set at 28 and the combined set at 32 or 34 ( cant remember) They will do ok but as others have said a stock HEI will outperform a dual point. Dual points allowed longer coil saturation which increased secondary circuit output. A stock HEI will put out more secondary voltage than any dual point I know of and there will be no points bounce.