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Thread: Question about ignition wiring unique to 1980 MGB

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  1. #1
    Jedi Hopeful
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    Question about ignition wiring unique to 1980 MGB

    In the last few weeks I've burnt up two coils in my 1980MGB. Now that the hubby has had time to reflect he has came up with some conclusions, some thoughts, and of of course some questions. He is thinking that the last coil burnt up because my Brothers were going by the Bentley "1978 & Later MGB" and the Haynes electrical diagrams -- both of which he is sure is not correct for an 80 MGB when they replaced a coil for me.
    <span style="text-decoration: underline">
    <span style="font-style: italic">Interesting Fact and quote from Moss:</span></span> "The original Lucas "Opus" electronic ignition used from 1975 to 1979 featured the ignition amplifier mounted on the distributor body. As this system proved unreliable, <span style="font-weight: bold">it was replaced in 1980 with the CEI system, which used a remote amplifier".</span>
    <span style="text-decoration: underline">
    <span style="font-style: italic">What The Hubby Thinks: </span> </span>

    1. The green white wire from the starter solenoid does not come into play even though it was left over in the harness from the previous years. Not needed because the coil uses 12 volts all the time.
    2. No distributor resistor comes into play.
    3. The resistive ballast wire does not come in to play even though it was left over in the harness from the previous years.
    4. The coil positive side is fed from the whit wire at the ignition and not the ignition relay. If it is fed from the ignition relay there is enough voltage feedback when the key is turned off that the engine will continue to run.

    <span style="font-style: italic"><span style="text-decoration: underline">What The Hubby Knows :</span> </span>

    1. The ignition circuit is completely different that that shown in the late MGB schematics.
    2. There are only two wires feeding the electronic (amplifier) on the 80 and they are a white and a white/black wire.
    3. The 80 model year can be distinguished very easy because it has a remote amplifier with the coil mounted on top of it.
    4. There are two wires, a red and a green, which feed the distributor from the amplifier.
    <span style="text-decoration: underline">
    <span style="font-style: italic">Questions For You The Experts:</span></span> Is the hubby right with what he thinks and what he knows? Has anyone ever drawn a schematic to show correctly the ignition wiring of an 80 MGB? I hope this post makes sense and is not to long and boring.


    Your turn

    Naomi (Owner of a 1964 MGB and a 1980 MGB. Each repaired hundreds of times but still loved &lt;img src=&quot;/ubbthreads/images/graemlins/smile.gif&quot; alt=&quot;&quot; /&gt;

  2. #2
    Obi Wan
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    Re: Question about ignition wiring unique to 1980 MGB

    OK, Naomi....having just fought this battle with our 1980 B...
    WHen we got it the ignition had been bypassed and a push button start added...so....

    we added an electronic ignition and new ignition switch. We pulled the entire harness because we thought it was the wrong one for our car...it just needed some tweaking.

    The first picture is the solenoid...the red and black on the front are from the coil.
    The black and white and green and white are from the starter.

    We cut and taped off those other wires because they were no longer needed with the electronic igntion.

    I don't know if ours is "right" for an 80 B, but when I trun the key it fires up. We played heck getting any pictures that resembled what we had underr our hood.

    Maybe these will help
    Attached Images Attached Images
    &quot;Duct tape is like the force. It has a light side, a dark side, and it holds the world together.&quot;

    Previous LBC's
    1977 MG Midget
    1980 MGB
    Present cars.......
    1986 Alfa Romeo (Our B's Italian cousin)
    1986 Toyota MR2 (Young son's project car)
    2002 GMC Envoy (Young son's commuter)
    1998 Toyota 4-Runner

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    Jedi Hopeful
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    Re: Question about ignition wiring unique to 1980 MGB

    Thank you so much for the pictures and message! It is odd how the 80MGB is wired and I do hope others will pipe in and we can see the different ways the 80 model are wired and if anyone has a period correct one. Thanks again
    Naomi (Owner of a 1964 MGB and a 1980 MGB. Each repaired hundreds of times but still loved &lt;img src=&quot;/ubbthreads/images/graemlins/smile.gif&quot; alt=&quot;&quot; /&gt;

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    Yoda PAUL161's Avatar
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    Re: Question about ignition wiring unique to 1980 MGB


    If this is it,
    Hard to believe the cost is over $300.00

    Remember, Never Forget
    We Live In The Land of The Free
    Because of The Brave

    How good it feels, the hand of an old friend! Longfellow

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    Jedi Hopeful
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    Re: Question about ignition wiring unique to 1980

    That doesn't look exactly like it. I have pictures but when I try to post them I get a message that they are to large and I don't know how to downsize them
    Naomi (Owner of a 1964 MGB and a 1980 MGB. Each repaired hundreds of times but still loved &lt;img src=&quot;/ubbthreads/images/graemlins/smile.gif&quot; alt=&quot;&quot; /&gt;

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    Jedi Knight Dave Richards's Avatar
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    Re: Question about ignition wiring unique to 1980

    For what it's worth (IMHO):

    We just went through this mess with a '78. Take that piece of junk out of your poor car and replace it with the older style 25D distributor. It's simpler and it works.

    I wish someone had been bold enough to tell me this initially!

    Call Jeff at Advanced Distributors. You'll be glad you did, <span style="text-decoration: underline">AND</span> it will cost you less than the replacement electronic module
    Helping Billy (WillR) with his '78 MGB...ahh, the memories!

    Dave Richards

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    Jedi Knight Dave Richards's Avatar
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    Re: Question about ignition wiring unique to 1980

    Quote Originally Posted by Naomi
    That doesn't look exactly like it. I have pictures but when I try to post them I get a message that they are to large and I don't know how to downsize them
    Use this, it's free and was recommended by a fellow BCF'er.

    PixResizer
    Helping Billy (WillR) with his '78 MGB...ahh, the memories!

    Dave Richards

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    Great Pumpkin tony barnhill's Avatar
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    Re: Question about ignition wiring unique to 1980

    Hi, Na - glad to see you.....looks like you're getting lots of help...I don't have an '80 to take photos of but I can agree with contacting Jeff - or, as an option, install a new Pertronix distributor from Moss.

    {Oh, for those of you who don't know Naomi...she's a Virginia mountain girl who drives the 'you know what' out of her MG's &amp; who isn't afraid to get her hands dirty working on them...she's finally convinced Bill (who's retired &amp; just wants to fish) to help her out with her cars....we need to help her solve the problem so she'll stay over here!}
    <span style="font-weight: bold"><span style="font-style: italic"><span style="font-size: 14pt"><span style="font-family: 'Comic Sans MS'"><span style="color: #006600"> Tony &quot;theAutoist&quot; Barnhill</span></span></span></span></span>


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    Yoda kennypinkerton's Avatar
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    Re: Question about ignition wiring unique to 1980

    Hi Naomi, you still have the Fiat, or did you manage to sell it?
    I Drank What? -Socrates 399 BC

    Kenny Pinkerton
    1977 MGB, 1984 Alfa Romeo Spider, 2006 Ford F150,
    2015 sublime green Dodge Challenger R/T, 2016 Ford Edge

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    Jedi Knight
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    Re: Question about ignition wiring unique to 1980

    Just a tip for those with the 80 style ignition. If the amp fails (rare) if you open it up, there is a GM (General Motors) HEI "chip" inside. A good parts store can cross over the number for you and the new GM part is cheap!! I am told, but have never verified, that the original GM chips are best, with the correct dwell.... The last one I bought was for a Jaguar, and was less than 50 bucks.
    Jesse Bogan
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    '93 XJ6
    '89 XJS coupe V12
    '87 Audi Turbo Quattro Wagon
    '67 Chevy Corvair coupe
    Uh ohh 64 Chrysler newport hardtop wagon

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    Obi Wan
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    Re: Question about ignition wiring unique to 1980

    Naomi,
    After looking at that piece, I know that ours doesn't have one. so, I guess the pics aren't much help. It was such a mess when we got it that we pulled the harness and dash and steering column wiring and reworked it all by tracing wires with a wiring diagram, I guess I got lucky cause it may not be right, but it runs great!
    Can't wait to get some wheels and rubber underneath so we can get it out of the garage...November will be one year and I generally like to say,"it only took us a year to get it running."
    &quot;Duct tape is like the force. It has a light side, a dark side, and it holds the world together.&quot;

    Previous LBC's
    1977 MG Midget
    1980 MGB
    Present cars.......
    1986 Alfa Romeo (Our B's Italian cousin)
    1986 Toyota MR2 (Young son's project car)
    2002 GMC Envoy (Young son's commuter)
    1998 Toyota 4-Runner

  12. #12
    Jedi Hopeful
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    Re: Question about ignition wiring unique to 1980

    Hey thanks a bunch folks and sorry I didn't introduce myself in the original post. Tony is right about one thing --- I do drive the daylights out of my B's and have just returned from a real Virginia mountain trip. Our B's are wonderful cars and I've owned em for decades --- well ever since I was sixteen.

    Thanks again and I always know where to turn to for "expert advice and fun folks".

    Oh, the Fiat is history -- sold it - and one of the most happy days of my life whe I saw it being driven away !!!!
    Naomi (Owner of a 1964 MGB and a 1980 MGB. Each repaired hundreds of times but still loved &lt;img src=&quot;/ubbthreads/images/graemlins/smile.gif&quot; alt=&quot;&quot; /&gt;

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    Re: Question about ignition wiring unique to 1980

    This is an old thread but I just recently started to revive a 1980 rust-free barn find my son-in-law rescued. The car has been dormant for 8 years or so. So far I repaired the ignition switch wiring, that had been cut and poorly spliced, changed the oil and filter and spun the engine to 50 psi oil pressure. In checking the ignition, I found that the original 1980 only distributor has been replaced by a brand new points type distributor, It has apparently never actually worked. The interior of the dizzy is bright and shiny and the cam follower wiper is clean and oil free as is the shaft lubricator batting. All of this is to try to find the best way of making the retro distributor work. The PO apparently thought the enhanced spark amplifier should be connected to the neg post on the coil, so the neg post has two wires, one from the amplifier and one that goes to the points on the dizzy. After reading this thread, I've decided to disconnect the amplifier and give it a try. Any comments?

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    Re: Question about ignition wiring unique to 1980

    I removed the wiring between the coil and enhanced spark module. Achieved spark at the points.

  15. #15
    Great Pumpkin DrEntropy's Avatar
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    Re: Question about ignition wiring unique to 1980 MGB

    If you have trigger at the points, you should be good to go. Rig the coil and plug wires, static time the beast and go for a spin!
    '64 MGB, '67 Lotus Elan S-3 DHC,'69 Lotus Elan +2
    '78 Alfa Romeo Spider-undergoing surgery: O=\*/=O
    '84 300D Turbo-"Diesela"-Now my Daily: Oo|≣|oO
    '02 Toyota Camry- SWMBO's 'new-to-her' Daily. <sigh>
    Chaos & Mayhem PTY, LTD..C.I.O. & Floor Sweepervisor

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    Re: Question about ignition wiring unique to 1980 MGB

    Thanks, Just need to button-up the carb.

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