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Distributor rotors


Datsundude123

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Points generally need 3 Ohms, while electronics work great with 1.5 (factory Datsun coil.)  Some electronics will accept a lower Ohm coil, but some will fry in short order if you drop below the 1.5 ohms on a 4 cylinder.  For example, the same system is used on a 280Z, but since its a 6 cylinder you can run a .8 Ohm coil with no issues, as it has to fire 50% more often and you need more input voltage to pull that off without running out of dwell time (to put it in the simplest terms.)  

 

Plug wires work best in the 1k - 3k Ohm range.  NGKs are roughly 10k Ohms.  If you run points, you can use 0 Ohm copper core wires if you like, but the 1000 Ohms will actually force coil voltage up a bit, providing a hotter spark at the plug.  Also, stay away from precious metal plugs.  Basic copper plugs will run the best on a  carbureted car, and be less likely to foul if the choke isn't working perfectly or you pump the pedal one too many times when you start it.  

 

As for your brother's truck running better than yours, that has more to do with the timing curve than dual points.  It likely had more precise timing at all (each) rpm so it was in better tune throughout the rpm band.  This results in faster acceleration.  If your timing is 5-10 degree out of whack from 1000-2500 rpm, it'll result in poor acceleration off the line, but still feel good while cruising.  This is the standard "smog" formula for vehicles sold in the US from 1973-1980.  The 1980 electronic distributor had a little better advance curve (timing profile as drawn on a grid based by advance and rpm) which is why people think its better.  Put the same advance curve in a points distributor, and points will outperform electronics.  Better yet, modify a stock single point distributor to have optimal timing for your engine and you'll have some REAL throttle response!  That's what I get to do for a living!

 

 

Would it be worth recurving an electronic dizzy for an L20? It was recommended to be by Ztherapy. Not sure what would be optimal though..

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No kidding. Recurve my dizzy, smart guy.

???  I remap distributorless systems too.  I'm currently running Megaquirt Pro3 on my flathead Ford with 3 custom 2-barrel throttle bodies.  I have also had MS on my MG Midget, and helped tune MS systems on quite a few radical motors as well as playing with diesel pump timing on thee dyno. We tuned a 4BT Cummins to over 400 hp and 700 ft lbs tq by getting pump timing correct, which is surprisingly just like recurving a distributor.  

 

Sitting on the bench at the moment are 2 MGC distributors, 2 Jaguar V12's, a 280Z, a TR6, a Chevy V6 (conversion), and  Lotus for the Big Dog Garage.  There isn't much I haven't seen or done, other than Ford or John Deere because they're always trashed.  You think you can offer me a timing scenario I can't figure out???  I call BS.   :rofl:

 

My choice in the L20b is a single point factory distributor, recurved to suit.  Its the most stable and consistent with the fewest side effects.  Side effects exist in all distributors and yo have to pick your poison.  If you can learn to adjust points, its the best scenario.  If you can't, go with electronics and a very good set of plug wires, like Magnacore.  

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Not your thread bro!

 

You're lucky people are actually taking the time to read your thread. The more replies you get.. the more it shows up on people's radar. Sit back, relax, and enjoy the knowledge being dropped in here. Your questions will be answered. 

 

And to a point you're right.. but we are staying on topic.

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From what you have provided to us it appears that your distributor is working

 

So that should work for my 77 l20b but for some reason I'm not getting spark at my spark plugs but I'm getting great spark from my coil and I have no idea why.


If your engine is turning and you have spark at the coil then that part of the distributor operation is working. Now all you need is to time the distributor so that it is pointing at the correct spark plug at the right time. Setting it to 11:28 should get you close.

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From what you have provided to us it appears that your distributor is working

 

 

 

If your engine is turning and you have spark at the coil then that part of the distributor operation is working. Now all you need is to time the distributor so that it is pointing at the correct spark plug at the right time. Setting it to 11:28 should get you close.

Thanks man! And if I were to go pick up a distributor cap would I get the cap for a 77 or 79 620? Because someone else on this thread said I had the distributor out of a 79.

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OK I just cked this out with the Acell coil and the ballast resisitor set up you have.

that should work

 

you say you have spark. Great

 

now its fire order and putting the spark plug wires in the right spot.

 

put back to TDC  then go counter clock wise fire order.

 

where the dist shaft is position in TDC then install the dist till it locks down and that will be number 1 and go CCW 1 3 4 2

 

 

Look up Hainz L series vid part 5 or 6 on youtube

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