single or dual points distributor?

[Dirttrack510]

I have both a single & a dual points dizzy. I'm not interested in electronic ignition, so which is better? Back in the old days racing distributors were all dual point. Both my distributors are in good shape, so which would be better in a race engine?

[josh_t]

dual for sure

[datzenmike]

Dual points increase dwell time and allow the coil to better reach saturation for a full spark at high revs. One set closes, then the second set closes, the first set opens but nothing happens because the second set are still closed, finally the second set open and the coil fires. Most dual points are only 4 degrees different but you may be able to increase that. Spark timing is set for when the second set open.

 

EI matchbox dizzys have maximum dwell built in, there are no points to replace, no points to set or file or adjust every 5K miles and draw more current through a special coil for higher output secondary voltage. In fact you have to open up the plug gap wider and never have to set the timing. I had one in my 620 for over 13 years and would drive it until it started acting up and then realize I hadn't even looked at the ignition in over 5 years and the rotor and cap needed replacing. Really, .... install it and forget it.

[Dirttrack510]

Very cool, thanks for the info... It's kinda what I expected, but I figured I'd double check before I bought new point and stuff and put the time into cleaning it up. Thanks again ;)

[Jesse C.]

All SSS distributors came with single points. The dual point where more of an emission setup. Unless you know points distributors and like messing with them, go with the electronic setup.

[mklotz70]

Yep...the dual point dizzy was an emissions item. It was setup to retard the timing in certain conditions....3rd gear decelerating I think. A lot of guys simply pull the second set of points out and run a single set. A couple of advantages I would see to the dual....if it's the stock dizzy for your car, then you don't have to try to remember which year/eng the other dizzy came from when you're trying to get a cap and rotor for it. Also...if you disconnect the wiring to the second set, you basically have a back up set of points in the dizzy already. You could simply move the coil wire on the side of the dizzy from the primary set to the other set in an emergency(although it will run a bit retarded, but should get you home).

 

Personally, I'd run EI like Mike said :)

 

You probably already know this, but I'll put this info here for the benefit of others running points. Once you tune your engine up and having it running perfectly....points set correctly with a dwell meter, timing set...yada, yada....you should NEVER need to adjust your timing again!!!!! If your timing changes or wanders, it's your points wearing out!! Replace the point, reset with a dwell meter and your timing will go right back to where it should be. Timing is a physical relationship between the hard parts in the engine, which doesn't change. The wear on the soft parts, ie...points....does change and that's all you need to mess with.

[pocket rocket]

why would you want dual points?? - twice the chance of problems for an almost un-measurable gain

 

Personally I would run a single point system over dual point anyday. But If given the choice I wouldn't use either.

 

Electronic is light years in front of any points set-up, both in performance & reliability.

 

either a factory electronic system or a luminition or similar conversion is by far & away the best option.

[john510]

If you dont use EI go with single points.

[banzai510(hainz)]

why would you want dual points?? - twice the chance of problems for an almost un-measurable gain

 

Personally I would run a single point system over dual point anyday. But If given the choice I wouldn't use either.

 

Electronic is light years in front of any points set-up, both in performance & reliability.

 

either a factory electronic system or a luminition or similar conversion is by far & away the best option.

 

 

 

 

EXACTLY!!!!!!!!!!!!!!

 

 

Put a pertronix in the single point dizzy.

[Dirttrack510]

For those that keep asking why I wouldn't want electronic ignition. It's a race car and my racing class dictates use of the stock ignition system, so points are my only option for my car, but my car was offered with both single or dual point ignitions, so I can use either, besides... I find points to be more reliable for me. If I burn up an electronic ignition I'm done for the night, if I burn up a set of points, I can be fixed for $10.00 in ten minutes.

[DanielC]

I would suggest you go with the single point distributer. The dual point can be wired to have a longer dwell time, but single point distributer on a V-8 engines have no problem running at 5000 to 6000 RPM. the amount of dwell that occurs with a V-8, at 5,000 is about the amount of dwell you have in a 4 cylinder at 10,000 RPM.

 

In the 1970's there was a crank fire ignition system available from Nissan competition. It would be hard to find now, but is that an option?

 

Found some old part numbers.

22100-U2800 SSS distributer, Hitachi D409-54K Single point

 

9/6-D2100 L-16/18 Crankfire ignition system.

 

9/6-D2101 L-20 Crankfire ignition system,

 

Part numbers are from a Nissan competition catalog, dated 3/82.

[banzai510(hainz)]

single point sss

[Ooph!]

Do your rules state "stock for year, make and model" or do they say something like "must be stock OEM?

If it's the latter use the electronic, most V8 stock car classes are using HEI distributors because the rules are interpreted to mean stock OEM for that generation of engine.

I'd use it unless it states otherwise.

[pocket rocket]

electronic is stock... maybe not for your model, but it is/was available from OEM.

 

You may burn up a set of points, and replace them, then a few nights later another set.... mean while the electronic distributor will continue to perform as should, night after night after night - there is a reason why just about every racing car now uses electronic ignition.

 

 

If you didn't tell your tech guys, I doubt they would know what your car/motor came with. I wouldn't regard that as cheating, that is simply exploiting the rules to your advantage.:cool:

 

You won't be able to run an MSD or similar, but I can't see why you wouldn't be able to run a factory stock Datsun electronic ignition

[Z-train]

Points belong in a museum or a garbage can.

 

If you have points,they "bounce".When they "bounce"-dwell changes.No way around this.Your call.

[zed]

one advantage of points over electronic - you can run maximum amps through points: if you run a Pertronix Ignitor, you must run a resistor, to limit the amps through the module to 4 amps - otherwise it blows. I know this from my own experience. This means limiting total spark energy to 4amps x 12volts=48watts total. Whereas with points the calculation is: 8amps (for 1.5ohm coil)x 12volts=96watts spark energy. Or have I got it wrong here?

[banzai510(hainz)]

ZED

Or have I got it wrong here?

 

 

 

You forgot the ballast resisitor of 1.6 ohms also in the circut.

 

pertronix is a electronic trigger not truely a FUUL EI system.

 

 

 

many a Unilite or pertronix system break due to not reading the instructions. Say to use with stock system. meaning with ballast resisitor or resisitive wire and stock OHM coil.

 

 

some people get away with it for awhile but they will break.

I havent had one go bad in the 10years of first installing one. Have 3 now and installed one in a Jeep.

Got few others from work to install on there cars. A Mustang and a Corvette.

 

Cost of a pertronix is the same as cost of a Matchbox on the used market. Take your pick.

 

 

Getting rid of points was the best move I had ever made in reliabilty in a Datsun!!!!!

This should be a datsun owners first move before wheels and other bling items.

Save alot of trouble shooting time.

[datzenmike]

The EI modules can easily handle a 0.76 - 1.1 ohm coil. This is the stock EI coil resistance values. When the motor is revved up and making a full 14.2 volts this works out to

 

C = V/R Voltage divided by Resistance = Current OR 14.2/1.1 = 12.7 amps. More if the coil resistance is lower.

 

Naturally this is not a steady draw of that amount as the module is turning on and off.

 

I can't think of any advantage to using points that a matchbox does not blow away. I've had one in my truck for 13 or more years of use including at least 6 x 2,800 mile and back trips across Canada, often compressed into 3-4 days of hard running. A minimum of 100K miles at least... so how many sets of points is that, the time to go get them and install, possible filing/adjusting them @5K miles intervals, re-setting the timing every change??? ... and I have a system that has about 30% - 50% more spark voltage?

 

 

 

You forgot the ballast resisitor of 1.6 ohms also in the circut.

 

pertronix is a electronic trigger not truely a FUUL EI system.

 

 

many a Unilite or pertronix system break due to not reading the instructions. Say to use with stock system. meaning with ballast resisitor or resisitive wire and stock OHM coil.

 

Absolutely! Pertronix simply removes the points and the bother of having to change or work on them.

[josh_t]

This should be a datsun owners first move before wheels and other bling items.

 

i'm way ahead of you. i plan on getting a matchbox dizzy right after i get all the parts necessary for it to run properly (new fuel pump, intake gaskets)

[Laecaon]

i'm way ahead of you. i plan on getting a matchbox dizzy right after i get all the parts necessary for it to run properly (new fuel pump, intake gaskets)

 

Yes but A series matchbox dizzys are easy to find. I mean last time I was at the junkyard both the 210's in the yard had it still there. But All the 620's had their dizzys ripped out. I have never even found one at a junkyard for a L motor.

[josh_t]

for the benefits, i would pay the 80-ish dollars you suggested for the matchbox if i had an l series. how much would you think is a good price on an a-series matchbox? is 35 too low for one in good shape?

[mklotz70]

Last time I compared the A series with the L series, the pin that hold the drive end is in a different place....just keep that in mind if/when you try to follow L series timing advice about where the rotor should sit at top dead center.

[racerx]

It depends, if you already have dual points and you are content with gapping them then that's okay..if you are thinking of pertronix later on then single...

[banzai510(hainz)]

I only suggest a Pertronix as I see alot of single point dizzys get thrown away when matchboxes are installed.

The matchbox is a Very good system.

 

L16 single points are getting harder to find but the later L20 ones can be fitted with a Pertronix if the meatal ring above the point lobe is machined off. Mishibishi single point dizzy will also work

 

I hear Troy Ermish at the "510 outlet" will take the single point dizzys if you have a stack of them gve them to him. He retrofits them for customers.

It better than seeing them stacked up outside in the rain rotting. Like I have seen with some 510 horders

[Z-train]

one advantage of points over electronic -

Points have NO advantage over elctronic.