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Technical Magneto on street drivers

Discussion in 'The Hokey Ass Message Board' started by 8ntsane, Sep 22, 2021.

  1. 8ntsane
    Joined: Jul 14, 2021
    Posts: 9


    Hello All
    I have a few questions for you magneto guys. I have a Scintilla magneto I picked some time ago. I was intending using it on my 383 SBC engine. I currently have a HEI dist now. First off, this mag has no advance, its locked. I have in the past ran a locked Vertex on my old race car without issues, but Im sure on the street is different world. So , can a mag without advance be converted to have advance? The next thing Im wondering about is running the tach. The mag I have has tach drives on it. But not wanting to use cable drive. Years ago with the Vertex , autometer used to sell this item that screwed into the tach drive, that a couple terminals that you could hook up to a regular tach. But not seeing them around now. Could be looking in the wrong places too.
    Any advice to running a locked mag on a street car, Im all ears.
    Also the tach, without punching a hole in the firewall for the cable would be a bonus as well.
    I was intending switching over to a 2x4 carbs and that HEI is too big to fit.

    Thanks Guys
    Deuces likes this.
  2. oldiron 440
    Joined: Dec 12, 2018
    Posts: 2,406

    oldiron 440

    I've only use a locked distributor on engines with plenty of duration and a loose converter. Starting with a smaller cam you might need a switch for ignition and one for crank. Crank it over then hit the ignition so your not fighting the starter.
    Deuces likes this.
  3. Have you removed the base and checked it out .
    Some have no advance,,,,and some are locked out .
    If it’s locked,,,you can change it to work.

    Also,,,,Autometer made a generator that screwed onto a tach drive and operated a tach .
    I’m not certain if they are still available ,,,,I haven’t seen one in years .

  4. What @Desoto291Hemi said about the Mag

    you can get an alternator off a diesel with a W terminal to get a signal to an electric tach and avoid the cable .
    Truckdoctor Andy and 427 sleeper like this.

  5. bchctybob
    Joined: Sep 18, 2011
    Posts: 3,252


    Hey VP, care to elaborate on the alternator/tach connection? What vehicle is the alternator from? How to calibrate alternator rpm to crankshaft rpm? Inquiring minds, Yada, Yada……
    VANDENPLAS likes this.

  6. I know vw used them in the 80’s for sure and caterpillar diesels have them as standard as well .
    Dodge Ram diesels can be modified easily to get a w wire as well.

    You would have to use a diesel tach that is calibratable ? Calbratied ? Calibraterized ?

    Is Adjustable !!:oops:

    I have installed a couple of these on diesel caterpillar engines and my shop has one of those nifty timing light gizmos where you stick a bit of silver tape to the crank pulley and point the light flasher tool at it snd it gives you an rpm reading .

    could use a hand held tach to do the same thing.

    stewart Warner makes a tach that looks pretty traditional.
  7. G-son
    Joined: Dec 19, 2012
    Posts: 826

    from Sweden

    I'm thinking that fuel economy would be very bad running with locked advance. It's an okay compromize for racing, as you generally keep the engine on high rpm & lots of throttle most of the time where the optimum adcance doesn't change much, and low rpm and off throttle performance doesn't really matter because you don't use that.
    On the street where high rpm and full throttle would be the rare exception from cruising power I suspect it will be rather horrible.
  8. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,301

    from Indiana

    I run a Magtech Mag in my SBC 383. Locked at 34 degrees. It runs great. I have the starter on the key with a mag ground toggle switch. Gotta get it rolling over before hitting the spark. Also, this way it gets oil pressure before firing.
    My tach went crazy with the mag. I called Autometer and they didn't have a solution. I ended up with a Tel-Tac. It works with mags.
    They were just cheap gauges, so I gutted the tach and mounted the Tel-tac inside it.

  9. 8ntsane
    Joined: Jul 14, 2021
    Posts: 9


    Sounds like you have had success running a locked ing timing. Maybe worth trying it out and see how it works on my engine. I will google Tel-Tach as well. Just cant see putting a hole for a cable drive. Thanks for your input.
  10. mohr hp
    Joined: Nov 18, 2009
    Posts: 364

    mohr hp
    from Georgia

    I think I have one of those tach drive generator things with matching tach. have to look at my inventory.
    VANDENPLAS likes this.
  11. I know you stated you don’t want to use a cable, but for those who do Ford tractors had an alternator or generator with a tach drive as well.
  12. cfmvw
    Joined: Aug 24, 2015
    Posts: 748


    I'm almost certain Dakota Digital has some sort of alternator signal converter to drive a tach.
  13. moparboy440
    Joined: Sep 30, 2011
    Posts: 713

    from Finland

  14. It don't need to have vac advance to run on the street. I have run vertex mags on cars and bikes on the street for years. My bikes were all kick start and I started running magnetos on bikes when i only weighed about 135-140.

    Now all the internet experts are going to give you a ton of reasons why it cannot be done. I have done it and they have read about it. Not that my experience makes any difference.

    Drop the bitch in time it and run it until you have to replace the magnets then rebuild it and run it some more.
  15. 8ntsane
    Joined: Jul 14, 2021
    Posts: 9


  16. 8ntsane
    Joined: Jul 14, 2021
    Posts: 9


    If you want to sell it, let me know.

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