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How To Install The Holley Dual Sync Distributor with Sniper EFI

Holley’s dual sync distributors were designed
to work with the new Sniper EFI system. Sniper EFI has the ability to control ignition
timing. It’s an optional feature, not required for
the normal operation but by enabling timing control, you’ll get more precise timing and
a better idle quality, I’ll show you how to install it now. Holley dual sync distributors come with a
hardened steel distributor gear. It’s compatible with most camshafts with the
exception of billet cams. If you have a billet camshaft, we recommend
you use a bronze gear. If your unsure of your cam’s construction
I recommend you contact the camshaft manufacturer and follow their recommendations. Before we begin the actual installation, you
first need to configure the ignition settings using the start up wizard and your three and
a half inch touch screen. You’ll need to turn your ignition system to
the run position but don’t crank the engine yet. On the Sniper home screen go ahead and select
the wizard’s icon. Next you’ll need to select the part number
of the Sniper throttle body that your using. The wizard is going to ask how many cylinders
your engine is, we’re running a V8. Go ahead and select the engine displacement
by sliding the curser and then click next. Now the wizard would like to know the target
idle speed, we’re running a 4 speed so we’re going to go ahead and select 750 RPMs for
our target. The wizard would also like to know what style
cam we are running, whether it’s a stock, street strip or a race style. We have a stock cam. Sniper is capable of controlling Nitrous,
we don’t have Nitrous on this engine so we’re going to select the none option. Now the wizard would like to know what type
of ignition system we are running. The steps for both a magnetic and dual sync
option are the same, I’ll walk you through those now. The first thing it’s going to ask is whether
or not your going to control timing, in this senario, yes we are controlling timing. Now it wants to know what you want the ignition
timing to be at wide open throttle, we’ll be conservative and select 32, click next,
go ahead and click the start icon and the wizard will begin installing a calibration
based on the information you just provided. When prompted turn the key off and then back
to the run position to complete the calibration install. Once you’ve completed the ignition system
configuration, we can go ahead and begin removing our distributor. First you’ll need to remove the negative battery
cable from your battery. Disconnect the power and ground wires from
your inductive coil. If you have an HEI, remove the power wire
and the connecting harness from the distributor cap. Next you’ll need to rotate the crank shaft
until it reads 50 degrees before top dead center on the compression stroke of the number
one cylinder. You can verify that your on the compression
stroke of the number one cylinder by tracing the plug wire from the number one cylinder
back to your distributor cap. If you remove the cap, the rotor should be
pointed in the vicinity of the number one plug wire. Another way you can verify that your on the
compression stroke is to remove the spark plug wire and the spark plug from the number
one cylinder, put your finger into the spark plug hole and as you rotate the engine you
should be able to feel air being pushed out. Go ahead and remove the cap and wires that
way we can determine the rotation of the rotor as we rotate the crankshaft. You’ll need to know this later on. Although it is not required, removing the
spark plugs from the cylinder heads will make it easier to rotate your engine. If your harmonic balancer isn’t marked all
the way out to 50 degrees, you can use a tape measure to measure the diameter of your balancer
and determine whether it’s a 6, 7, or 8 inch. Use the chart included in the instructions,
from the 0 mark, measure the appropriate distance and make a mark on your harmonic balancer. Go ahead and disconnect any remaining wiring
or vacuum hoses that may be still attached to the distributor. You can loosen and remove the distributor
hold down now, and once that is complete, your distributor should lift out. Don’t forget to go ahead and check and make
sure the new distributor seats fully and doesn’t bind or bottom out on the oil pump drive. A quick way to check this is to instal the
new distributor without the gasket and make sure it seats fully on the mounting surface. If it doesn’t fully seat, your heads or engine
block may have been milled, you’ll need to do a little further investigation. Holley does offer a dual sync distributor,
part number 565-104, that has an adjustable slip collar. Follow the instructions to ensure proper gear
engagement. If everything checks out, you can go ahead
and remove the distributor and install the gasket. If your engine has been previously just apply
some oil to the gear. If the engine is new or has not been run for
a while, go ahead and coat the gear with paste or break in lube. Now we can install our dual sync. Remove the cap and position the rotor so it’s
pointed in the direction that you’d like to designate as the number one cylinder. The rotor will rotate slightly as you install
it so if the rotor is not pointed to the spot that you planned, you’ll have to lift up the
distributor and rotate it slightly until it points to the correct spot. You can designate any position as the number
one plug location but it may be necessary to rotate the oil pump shaft to get it to
mesh with distributor shaft. You can do this with a long flat blade screw
driver or wrench, be sure the distributor is fully seated before proceeding. Now you need to plug in the optional adapter
harness, part number 558-493, it plugs directly into the 10 pin connector coming from the
dual sync. The pink wire, needs to be run to a clean
12 volt switch source and you can connect the purple and green together from the connector
that comes from the Sniper wiring harness. If you plan on controlling timing using your
dual sync distributor, you’ll need to wire in the coil driver, the pink wire goes to
switch 12 volt ignition source, the black one goes directly to a ground and the white
one needs to be spliced in with the white wire thats included in the auxiliary harness. The gray wire, you can run directly to the
negative terminal on your inductive coil. Another way that you can control ignition
timing using our Holley EFI dual sync distributor is to connect it to a capacity discharge box
like an MSD 6AL. Using the included auxiliary 10 pin harness
connector, connect your white wire directly to the CD box. Once you finish making all these connections,
you can go ahead and reconnect the negative battery cable directly to your battery, but
you’ll want to leave the positive wire at your inductive coil disconnected for now. Now we’ll need to turn the key to the run
position and power up our Sniper and our dual sync. With the distributor cap removed, locate the
crank sensor as well as the crank and cam LEDs. Note that LED on represents digital falling
and LED off represents digital rising. Slowly rotate the distributor housing but
do not rotate the crank shaft. Slowly turn the housing clock wise until the
crank LED just goes off. Now turn the housing counter clock wise until
it just comes back on. For engines with a counter clockwise rotor
rotation, you’ll first need to turn the distributor housing until the block crank sensor lines
up with your rotor. Now slowly turn the distributor housing counter
clock wise until the crank LED goes off. Now you’ll need to turn it back clock wise
until the crank sensor just comes on. Go ahead and reinstall your distributor hold
down, and lightly tighten it. Once you’ve completed this step, you can go
ahead and verify that the rotor is pointed in the direction that you want it to designate
as the number one cylinder. You’ll also need to verify that the harmonic
balancer is still 50 degrees before top dead center. Make note of the rotor position as you install
the new cap, designate this as your number one cylinder. Starting with the number one terminal, install
the rest of the plug wires according to your engine’s firing order. If you are running an HEI distributor before
you installed the dual sync, you’ll need to install an inductive coil. Find a suitable mounting location, connect
the gray wire from the coil driver directly to the negative terminal on the coil, and
your switch power wire will go the positive side of the coil. Tighten these connections now and install
the coil wire from the coil to the distributor. We’ll now need to verify our static timing
using the three and a half inch touch screen and the timing light. Do this by selecting the tuning icon on your
home screen. Select system, then static timing. Now slide the curser to 15 degrees and click
set, verify that you have 15 degrees at timing before top dead center at your harmonic balancer
with a timing light. If the balancer does not read 15 degrees before
top dead center, it may be necessary to loosen the distributor and adjust it accordingly. Don’t forget to re-tighten it when you are
done. Once you have verified that you have 15 degrees
of timing, go ahead and click clear on the handheld. This completes the static timing verification
process and the Sniper ECU is now controlling the timing. Now that the timing has been verified, the
installation of your Holley dual sync distributor with Sniper EFI is now complete. To see the complete, step by step installation
of EFI on our 1967 Camaro, visit the Holley performance channel on Youtube. Thanks for watching, for more information
on Holley’s dual sync distributor or Sniper EFI, visit our webpage at

15 thoughts on “How To Install The Holley Dual Sync Distributor with Sniper EFI

  1. Any reason why after installing dual sync soon as I give the car throttle it instantly goes to total timing? 15° at idle touch throttle right to 32° what would cause that?

  2. Does this supersede the video last year showing the distributor lockout and etc..I am thinking of replacing the HEI for this if it is as simple as this plug & play or are there any Caveats to this I have my Sniper in/on a stock 350 700R and 373 Tru Trac old 64 C10. I have not done anything to the set up since I got my Air Fuel down pat I have not uploaded anything to the Sniper itself but I did have my trans shift points changed a bit by the trans guy its a non electronic trans

  3. My engine builder said if I start it at 50° btdc that it'll blow holes in the top of the Pistons, I'm thinking this is just the wide open setting, and the computer will adjust it to 15° , just want to be sure before I do it!

  4. How do you set the timing curve? What if I want to have my car idle at 12 degrees, 36 degrees at 5000 RPM and 32 degrees at 6000 RPM, can I do this? Will the electronics remember its setup if the battery cable is pulled?

  5. I am using this system on a small block Chevy 350. Has a street strip cam. I am getting popping through the sniper carb during acceleration. Timing is set to 15 degrees at idle and 30 at WOT. Cruise setting also 30. Do you have a setting that is close enough to start off with and adjust as needed. I don’t want to hurt the motor.

  6. I want to install this in a mercruiser 260. Is this distributor marine approved? Will in see a performance increase? Is the timing curve appropriate for a marine application?

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