5.7 Hemi Engine swap on 70 RR (Project)

New Hemi Engine Swap

  1. 5.7 hemi

    5.7 hemi FBBO Gold Member FBBO Gold Member

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    Running a dead head system? The Gen 3’s need 58psi.
     
  2. Caterpillars

    Caterpillars Well-Known Member

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    Tachometer issues;
    Got my fuel issues solved and car is running good. I haven't had much time to work on the RR in a while but tinker when I can. One problem I've run into is my "tic toc" tach. not working and need some help deciding what to do before I throw parts at it. I bought a digital conversion board from "Real Time Engineering", https://www.rt-eng.com/index.php/RTE_67-74_Tach_kit.html This replaces the old analog board (which was fried) to a digital board. It wasn't a piece of cake to install but not bad. Problem is my tach. isn't working. I took the dash panel out again and check everything - seem to be good but tach only flutters when engine is running.
    I went back to my engine installation manual and they talk about providing a tach loop with the crate motor wiring harness - which is what I hooked into. The manual also says "The tachometer loop is provided for the user to add an aftermarket tachometer that is made for multiple ignition coils. It does not supply a standard tachometer signal". Bingo. So I call Realtime and told them my problem and ask for suggestions - "Our board was designed to work with the following;
    1. Points
    2. Electronic Mopar Ignition
    3. MSD electronic ignition using the "tach" output from the MSD box (This is a 12V square wave)
    4. Pertronix electronic ignition module.
    We have no knowledge of the multiple coils type tach signal."
    Ok, so the board is providing a "12V square wave" and the tach loop is providing a multi coil signal.

    tach1.JPG

    Their has to be some conversion and someone on this forum must of run into this.
    I found some stuff on Summit;
    https://www.summitracing.com/parts/msd-8920?rrec=true
    https://www.summitracing.com/parts/msd-8918?rrec=true
    https://www.summitracing.com/parts/atm-9117?rrec=true
    https://www.summitracing.com/parts/dak-sgi-8e?rrec=true
     
  3. 5.7 hemi

    5.7 hemi FBBO Gold Member FBBO Gold Member

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    MSD makes a tach adapter for the Gen 3’s. It taps off the #7 coil wire(forget which color) and then you can hook you tach to the wire off the MSD.
     
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    • Caterpillars

      Caterpillars Well-Known Member

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      Thanks for your suggestion 5.7. I'am looking at the MSD stuff and there is a bunch. Do you happen to know the number of the tach adapter you have had experience with?
       
    • 5.7 hemi

      5.7 hemi FBBO Gold Member FBBO Gold Member

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      MSD has 2 of them, I forget which one I used, also my dad had to use 1 for his FAST EZ EFI conversion. I do know one of them is list for the Gen3 Hemi swaps.
       
    • Caterpillars

      Caterpillars Well-Known Member

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      Well the tach. is still an issue and sometimes you need to move on to get away from frustrations. So I moved on to my alternator problem, now on my third alternator (thanks goodness for warranties). The new alternators are controlled by the PCM and as soon as I would plug my field (PCM) wires to the alternator you could smell it smoking. Have the main wire going to the starter which is linked to the starter relay which goes to the battery. The gremblems from the old to the new are coming out on this car. It's really neat to have everything power but the old systems weren't designed to handle the power fans, AC, computers, all driven by a 160 amp alternator. - and everything was running through my amp meter which was designed for about 60 amps. More than my alternator was melting - my bulkhead connects were frying and the wires were melting. Good new is I think it is savable. First I need to bypass the amp meter (wanted to keep the dash original - not happening). There is a blog that tell you how to bypass the amp meter;
      https://www.forbbodiesonly.com/moparforum/threads/bulk-head-connectors.177313/
      http://www.madelectrical.com/electricaltech/amp-gauges2.shtml
      I have it about half done - I think this may solve a lot of problems, especially future ones.
      From one frustration to another, but I love it....
       
    • Jeff Brundage

      Jeff Brundage Well-Known Member

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      I used the Dakota Digital adaptor for my 6.4 hemi swap. You can set it to work on a bunch of different outputs and inputs. SGI-8
       
    • Jeff Brundage

      Jeff Brundage Well-Known Member

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      I know it’s a big expense but git rid of the old wiring harness. If you have melted some wires that you can see, you probably have some melted you can’t see. All that old wiring is going to give you grief once you start driving it. At the very minimum carry a fire extinguisher!
       
    • Caterpillars

      Caterpillars Well-Known Member

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      First, I called Dakota and talked to their tech support. They don't know if their SGI-8 will do the conversion - they need to know what there products does! Still investigating but thanks for your input Jeff. Question, does the wiring harness on your 6.4 provide a tach. loop?
      Second, I think a fire extinguisher is a good idea in any of these cars - the design is bad. But I think getting rid of the amp meter is definitely a good idea. I hate the idea of adding aftermarket gauges, but the stock ones really do suck. I'll take some pictures of my damage and doing the conversion - will update shortly.
       
    • Caterpillars

      Caterpillars Well-Known Member

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      Ok so I bypass the amp meter and followed the directions given previously, some pictures;

      Hard to see but wires starting to burn inside the firewall

      IMG_5686.JPG


      Things were getting toasty - top 4 and bottom 2 are the same circuit. Goes in from the alternator and comes out using fuse-able link to starter relay.
      IMG_5706.JPG

      Drilled out the upper right on the top connector. These two are used for ac and are not going to be used for anything. Could of used the damaged ones but figured they had enough.
      IMG_5707.JPG
      Pretty simple, just used a drill bit and drilled through the firewall. Took out the gauge cluster and eliminated the amp meter by taking off the wires and connecting them together. I used a fuse here - know it's overkill but some added protection.

      IMG_5692.JPG IMG_5693.JPG IMG_5694.JPG IMG_5695.JPG

      I then connected the two wire going through the bulkhead to the damaged wire on the inside of the firewall.

      IMG_5705.JPG

      Finally I connected the black to the alternator and the red to the starter relay using another fused link.

      IMG_5708.JPG

      Now I need to reinstall my gauge cluster, but I think I will attempt to convert my amp meter to a volt meter following a person that has done it on a non rally dash. Just trying not to add gauges to the bottom of the dash. Will let you know how that works.
       
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      • Jeff Brundage

        Jeff Brundage Well-Known Member

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        Yes I had a tach output on the harness i got from hotwire
         
      • Caterpillars

        Caterpillars Well-Known Member

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        Converting amp to volt meter - wasn't that bad. Started with a cheap volt meter I found on Ebay;

        voltmeter.png
        Ripped it apart and ended up with;
        IMG_5868.JPG

        Attached it to the old amp meter face with the plastic type screws the came with the new meter. The rivets you drill out won't exactly match so you have to make a little wider space. Doesn't look great with the screws, but when you put the cover back on you won't see them. I thought at this point I may get lucky because the studs extended out the back about an inch - this is good because you won't have to chop up the old bracket that came with the original amp meter. The face plate and new meter is light and shouldn't require much to hold it in the housing.

        IMG_5870.JPG

        I drilled two holes in the gauge housing (carefully) and slipped the gauge in. I put shrink wrap on the positive stud and nutted it down with the existing nuts from new gauge (I put a rubber washer to keep the post from shorting to the housing).

        IMG_5871.JPG

        IMG_5880.JPG

        Cut an old gauge pin I had and JB'ed it to the pin that came with the new gauge (try not to get JB weld on the pin).

        IMG_5878.JPG

        There is only one place I could find a volt gauge facing for rally dash - couldn't find anyone that sells it so I had to make my own. Not done, but it's a close match. I gave my template to a friend who is good with a Circuit machine and he is going to make a dozen. Should have some extras for someone in need.

        IMG_5881.JPG


        IMG_5882.JPG

        Going to run a wire from the positive pin to the ignition switch wire. The negative is grounded to the base already.

        Other pictures;

        IMG_5869.JPG

        IMG_5867.JPG
         
        Last edited: Feb 21, 2020
      • Caterpillars

        Caterpillars Well-Known Member

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        Ok, received my volt gauge stickers and am excited to get this together;

        gauge stickers.JPG

        Came out great on the gauge. Note; when pressing on gauge pin make sure you connect a battery or charger to the new meter and measure the voltage with a volt meter, then put the pin on as close to the voltage as possible on the gauge.

        voltmeter gauge reading.JPG

        guage finish.JPG

        Was going to wire the positive side of the new voltmeter to the washer bottle switch, but the plastic melted and now my switch is bad - always something. Need a new switch. Will be back..
         
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        • Caterpillars

          Caterpillars Well-Known Member

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          Update; Well got my new windshield washer bottle switch and installed it. I put the dash cluster in and hooked up all the wiring (these big hand don't help). Turn on the ignition and the volt meter didn't work (what the F). Check everything and power was at the voltmeter. I felt I must of burn the meter while soldering the wire to an ignition source. Off with the gauge cluster again. On the bench I tested again and nothing. I took the face plat off and the meter started working - the face plate was hitting the pin which kept it from moving. Took a dremel tool and shaved off a little metal in front of the pin and put everything back together. The voltmeter works. While I had the dash cluster off I installed the solenoid and ran the hoses for the air grabber - the next nightmare to work on. Also going to work on the tach signal again. Need to get this running before my gas gets to old. When I first started doing this project a friend of mind told me put a 383/440 or 426 in this car and be done - beginning to think he was right. This car has me thinking of Tyson, “Everyone has a plan until they get punched in the mouth.”
           
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          • Caterpillars

            Caterpillars Well-Known Member

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            Going to try the Autometer Tach Adapter 9117;
            https://www.autometer.com/tach-adapter.html

            This should convert the muticoil signal to a standard tach signal so I can use my Tic Toc tach. Comes 4/11, will let you all know how it works.
             
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            • Caterpillars

              Caterpillars Well-Known Member

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              Ok, haven't been on in a while. This virus thing is scary for us older folks, and now that they are reopening Texas its really scary. I know there are a lot of folks suffering and no job, no money, equals no food. But for folks to ignore the threat without an available vaccine is dangerous. Anyway I installed my tach adapter tonight - couldn't believed it worked. After investigation I decided on the "AutoMeter" 9117. Someone was selling one for $80 on Ebay - guess they couldn't get it to work, or maybe they couldn't figure out the directions (terrible).

              tacha2.JPG

              For Mopar's AutoMeter said to cut each individual coil and rewire it through the adapter (shown above). I couldn't believe this setup so I called their tech. support and they told me it was the only way they could get it to work. I asked about the "tach. loop" that was on my wiring harness, and was told that mopars don't have a tach. loop or at least they have never seen one. I was ready to abandon ship but thought I would try to do something with the tach. loop. I cut the tach loop in half and measured the voltage on each wire with the ignition on - one wire had voltage and the other not. Connected the red wire to the loop wire with voltage and connect the red/green to the other. Hooked the grey to the "tic toc" tach wire and the black to ground. Turned the car on, presto.

              tacha1.JPG


              tacha4.JPG


              tacha3.JPG

              Look cool that both the clock and tach. is working. Now it's back to the alternator.

              Note: Talked to Jim from Autometer tech support and gave them the result of the 9117 install. Looks like they are going to review their directions.
               
              Last edited: May 8, 2020
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              • 70chall440

                70chall440 Well-Known Member

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                Excellent information, love it when crap works right. Hard to beat the looks of a functioning Tic Toc Tach.. I have a 68 Charger cluster for my 70 RR that has a Tic Toc Tach in it, no idea if it works but I am thinking about whether to keep it, source a 70 cluster or make a custom cluster.
                 
              • Caterpillars

                Caterpillars Well-Known Member

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                Ok, so I'm having trouble with my alternator and have done everything I can think to do and it's still overcharging. I bought two new alternators online and they both burnt up, so I went to O'Rieley's and bought one. I wired the battery to the starter and another wire from the starter relay to starter. I also have a wire from the ignition switch to the alternator but not used yet. The generation 3 wiring harness has field wires to a snap on plug that goes to the top of the alternator and have a wire going from the main alternator lead to the starter relay which in turn goes to the battery. When I plug in the field wires the alternator goes to 20 volts and start popping fuses. I then used a voltage regulator and wire it in (taking off the field wires from the wiring harness), same problem. I talked myself into thinking it was the alternator, so today I went and traded for a new one at O'Rieley's. Hook it up, same thing (WT****). What am I doing wrong????? Got to be grounded somehow. Confusing but any thoughts?
                 
              • 70chall440

                70chall440 Well-Known Member

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                Can you post a wiring diagram? It sounds like you are back feeding the alternator somehow. Where is the charge wire (main big wire) from the alternator going? I am not familiar with the wiring requirements of a new gen Hemi but I wouldn't think it would be all that different that older vehicles conceptually (but I could be way wrong)
                 
              • 5.7 hemi

                5.7 hemi FBBO Gold Member FBBO Gold Member

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                The factory computer controls the alternator output. You can bypass this setup by using the old school Mopar charging system. Give me a minute to find it.
                 
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