Register now to get rid of these ads!

Technical Mallory Flat top Distributor - Correct Coil/Resistance

Discussion in 'The Hokey Ass Message Board' started by TimCT, Oct 29, 2019.

  1. TimCT
    Joined: Jun 6, 2017
    Posts: 169

    TimCT
    ALLIANCE MEMBER

    I've spent the last few days combing threads about Mallory dual point flat top distributors, and I haven't been able to land on a definitive answer. So sorry in advance if this has been covered and I just didn't see it!

    What I have is the vacuum advance version, which I think makes it a ZC-310, instead of the standard YC. Its going in the SBC in my '57 Chevy. I want to stick with points. The points in the distributor are in great shape, and it came with a brand new set of Mallory points as well, and I don't want to burn any of them up.

    So, do I need a ballast resistor? I've got the Bosch blue 00012 coil, which should have a primary resistance of 2.93 ohms, though I'll measure mine tonight. I've seen recommendations for a 1.5 ohm coil and a 1.5 ohm ballast resistor, but would a coil with almost 3 ohms of resistance do the same job without having to add a ballast resistor? Or am I thinking about this the wrong way?

    20191020_160854.jpg
     
  2. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 27,691

    Jalopy Joker
    Member

  3. TimCT
    Joined: Jun 6, 2017
    Posts: 169

    TimCT
    ALLIANCE MEMBER

    Thanks for the bump @Jalopy Joker !

    I measured the coil just now, got 3.2 ohms.
     
  4. TimCT
    Joined: Jun 6, 2017
    Posts: 169

    TimCT
    ALLIANCE MEMBER

    Maybe I'll ask a different way. Did all GM points systems call for a 1.5 ohm coil and 1.5 ohm ballast resistor/resistor wire? Is the Mallory a special case?

    I probably would have put it all back to stock, but the PO had an HEI, and what was left of the original wiring crumbled if you looked at it too hard. I got a new HEI ignition harness from AAW before I went down the points road, so I'm thinking that with this coil, I can just hook up the 12v ignition wire that was destined for the HEI to the + side of the coil and be done with it. Just wanted to check before I wrecked anything.
     

  5. Truck64
    Joined: Oct 18, 2015
    Posts: 5,211

    Truck64
    Member
    from Ioway

    It should work. @GMC BUBBA would be the guy to ask.

    It loses the extra jolt of juice at startup that a resistor divider provides. I don't know if that factors but they did it that way for a reason.
     
  6. Moriarity
    Joined: Apr 11, 2001
    Posts: 22,248

    Moriarity
    SUPER MODERATOR
    Staff Member

    yup, single point or dual point. 1.5 ohm coil and 1.5 ohm resistor. that is what I have on all of my cars, some single point and some dual point mallory.
     
  7. TimCT
    Joined: Jun 6, 2017
    Posts: 169

    TimCT
    ALLIANCE MEMBER

    Okay, thanks for tagging him for me!
     
  8. Moriarity
    Joined: Apr 11, 2001
    Posts: 22,248

    Moriarity
    SUPER MODERATOR
    Staff Member

  9. TimCT
    Joined: Jun 6, 2017
    Posts: 169

    TimCT
    ALLIANCE MEMBER

    Thanks @Moriarity ! I think I read that thread a while back but couldn't find it again. Must be the reason I got the Bosch coil. Sounds like either setup would work, that particular coil with no resistor, or a stock coil with a 1.5 ohm resistor. Stock setup has the slight edge because it divides the heat generated by the resistance into two places,instead of just the coil.

    I wonder if this is the sort of thing that I'm overthinking, and there are plenty of examples from both camps running around on the streets just fine.
     
    Moriarity likes this.

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.