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Thread: Would you use a dual sync on a fresh install?

  1. #1

    Question Would you use a dual sync on a fresh install?

    Hi. I'm having pretty much decided to ditch my MSD distributor for a Holley Dual Sync Distributor on my car build. The question is, would it be best to get the car running and Sniper Learned with my existing MSD vacuum advance distributor, or go straight in with the Holley Dual Sync and Sniper EFI install at the same time? The instructions say get it's best to get it running without timing control first, and then switch it on. Can the Holley Dual Sync Distributor operate as a normal distributor before adding timing control? Thanks for your help. Andy

  2. #2
    Join Date
    Dec 2009
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    Connecticut
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    Quote Originally Posted by andy302 View Post
    ...or go straight in with the Holley Dual Sync and Sniper EFI install at the same time?
    Yes, this has been discussed before.

    The instructions say get it's best to get it running without timing control first, and then switch it on.
    I don't agree with that. Using the Holley Dual Sync Distributor is just too easy.
    https://forums.holley.com/showthread...8495#post98495 (Read this thread for more info.)

    Can the Holley Dual Sync Distributor operate as a normal distributor before adding timing control?
    No.
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  3. #3
    Join Date
    Dec 2017
    Location
    Hollister, CA
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    Hi Andy. I was thinking the same thing. Stick with a known good ignition system first, then upgrade the ignition after the Sniper is for sure up & running. I was going to leave my Pertronix classic look distributor in, but changed my mind for a few reasons.
    As Danny has said, installing the dual sync distributor is very easy. I came to the realization that I didn't want to go back & add the ignition module and redo my wiring after the fact and increase my workload. I also didn't want to have to change vacuum lines around that I would ditch anyway when installing the dual sync distributor. I left the timing control off as the installation procedure suggests, and when I went to fire the first time, it started crisply in seconds.

    Due to a bonehead maneuver and deleting my configuration file, I had to re-first-start & self-tune all over again. This time, I set up my parameters with ECU controlled timing. It was definitely not the crisp start as with timing control off, but it wasn't any more difficult than a cold carburetor with no choke. Coming off idle and trying to hold 1200-1500 RPM, the engine couldn't stabilize and quit. It would restart fine. I drove it for half an hour or so, and didn't have any problem stalling at all.
    On the second cold start, there was no issue at all. The idle followed the RPM profile I had setup on my computer and uploaded to the ECU. My guess (and I'm not a rocket scientist) is that the ECU just needed to Learn what my engine needed. I have a bored out 302 with a somewhat lumpy cam, so your configuration may behave differently.

    If you feel the need to start it for the first time with timing control off, no harm there. It's easy enough to change to ECU controlled timing later. But as for leaving a different distributor in, I would say that it just isn't necessary.
    Hope that helps! Kevin

  4. #4

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    Thanks that’s all great info, and a bit more reading to do! This forum is a really good one. Cheers!

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