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308 tach 'signal splitter', dual->single conv'n

Discussion in 'Technical Q&A' started by rufus, Oct 19, 2005.

  1. rufus

    rufus Karting
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    Nov 6, 2003
    150
    Toronto & St PetesFL
    Full Name:
    Pete Gorrell
    '82 GTSi dual distrib to single (Millermon) conversion. Distrib works great, but Ben's stunt box to fool my (4cyl) tach doesn't. I need a splitter that discards every second pulse. I may also need an amplifier (I'm using MSD 6AL, MSD has something but the descriptions I've found aren't very clear.)

    I know some folks out there have solved this, I even have a faint memory that someone sells a stunt box to do it, but that info probably died with the old archives.

    I did check the existing archives, but what I found was inconclusive.

    I'd be grateful if anyone can recall the answer.

    Pete G.
     
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  3. Doug

    Doug Formula 3

    Nov 13, 2003
    1,467
    Louisville KY
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    Doug
    I tried Millermons little homemade thing as well as the Dakota Digital splitter. Neither worked on my '76 308. I eventually sent the tach to Palo alto Speedo and it is recalibrated spot on. Cost was originally quoted $175, but then my tach needed a newer type circuit board that they charged me an extra $50 for. The later models I don't think need the board.
     
  4. Sean F.

    Sean F. F1 Rookie

    Feb 4, 2003
    3,003
    Kansas
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    Sean F
    The dokota has to be completely shielded from all signals in the engine bay. Some one noted that he could get it to work if he took it and laid in hanging on the fender near the rear wheel while the car was on. As soon as he put it back into the engine bay area it freaked out.

    Did you try mouting it right in front of your tach under the dash instead of under the hood?
     
  5. Matt Morgan, "Kermit"

    Matt Morgan, "Kermit" Formula Junior

    Nov 12, 2003
    405
    Ferndale, WA
    #4 Matt Morgan, "Kermit", Oct 19, 2005
    Last edited by a moderator: Sep 7, 2017
    According to one tech @ Dakota, the unit has very little tolerance wih outside electrical impulses. After mounting everything together, nice and neat, the tach would blip and go dead. So we moved it to the rear firewall, and got it away from any spark, coil, etc. Performs flawlessly now. In the pic, I pulled up the rubber sheild that went over it (inner tube piece), so it could be seen. The unit didn't want to work any where near an MSD box, or coil 'til we did this move.
    HTH
    Kermit
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  6. rufus

    rufus Karting
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    Nov 6, 2003
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    Toronto & St PetesFL
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    Pete Gorrell
    Doug, Sean, Kermit, thanks! PA quoted me $215 plus ship etc, I may end up there but I shy away from pulling the tach if there's any way to avoid it.

    Kermit, my MSD is in the same place as the old digiplex's... where did you mount the Dakota? And did you need an MSD amplifier?

    Tx!

    Pete G.
     
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  8. Doug

    Doug Formula 3

    Nov 13, 2003
    1,467
    Louisville KY
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    Doug
    The tach pull was really not that difficult, at least in the GT4. You can slide the whole dash face out and disconnect the 2 or 3 leads. Unscrew the 2 clamps and it comes right out with everything else intact. Put the dash back in and just drive without the tach until you get it back from PAS.
     
  9. Matt Morgan, "Kermit"

    Matt Morgan, "Kermit" Formula Junior

    Nov 12, 2003
    405
    Ferndale, WA
    #7 Matt Morgan, "Kermit", Oct 20, 2005
    Last edited by a moderator: Sep 7, 2017
    Pete,
    Here is a couple of pics that may help. The car is an 82 Mondy, but should be very close to the 308's. If you look below the MSD and coil, in the back, you can see the Dakota. I sheilded the MSD with SS to cut heat effects.
    In the second pic, it is pretty well self explanitory. The rear wall and drop down gears are good referance. I didn't need any other adaptor with this mounting. The tach is smooth, never missed a beat, and is a bit closer to real RPM than most compared to the dyno tach. I have seen stock ones off almost a thou.
    HTH
    Kermit
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  10. Sean F.

    Sean F. F1 Rookie

    Feb 4, 2003
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    Sean F
    Kermit was the one I was thinking of!

    Kermit, are you making a single dizzy conversion kit for the 308 series with Ford or Chrysler parts and the Dakota?
     
  11. Matt Morgan, "Kermit"

    Matt Morgan, "Kermit" Formula Junior

    Nov 12, 2003
    405
    Ferndale, WA
    Yes Sean, I am. but it is based on the Crane Digital Distributor, I believe the cap is the same as the Ford though. E-mail if you wish as I try not to get commercial on the forum, out of respect for the vendors who are paying.
    Kermit
     
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  13. JTranfield

    JTranfield Formula Junior

    Dec 29, 2003
    665
    NYC, London
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    J Tranfield
    I am in the same position and will eventually send mine off to PA. Out of interest is it easy to remove?
     
  14. Dave

    Dave F1 Rookie

    Apr 15, 2001
    2,722
    Little Rock
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    David Jones
    I removed mine, wasn't that big a deal, and sent it to PA.
     

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