Installation Instructions for 0-80586

Installation Instructions for 0-80586
COMPETITION CARBURETORS
MODEL 4500 HP DOMINATOR
Installation and Adjustment Instructions
WARNING! These instructions must be read and fully understood before beginning installation. Failure to follow these instructions
may result in poor performance, vehicle damage, personal injury, or death. If these instructions are not fully understood,
installation should not be attempted.
NOTE: These carburetors are not legal for use in California on any pollution-controlled motor vehicle.
INTRODUCTION:
Holley Performance Products cannot and will not be responsible for any alleged or actual engine or other damage, or other conditions resulting
from misapplication of the carburetor described herein. However, it is our intent to provide the best possible products for our customer; products
that perform properly and satisfy your expectations. Should you need information or parts assistance, please contact our Technical Service
Department at 1-270-781-9741, Monday through Friday, 7 a.m. to 5 p.m. Central Time; please have the part number of the product you
purchased when you call.
REMOVAL OF OLD CARBURETOR:
WARNING! Prior to and after installing your new carburetor, manually operate the throttle lever, checking for any sticking or binding.
Failure to do so may result in a runaway engine or a wide open throttle condition, which could result in engine damage
personal injury, and/or death.
NOTE:
Make a visual inspection of the carburetor, looking for any missing parts, bent levers, or any possible shipping damage.
1.
Remove the air cleaner.
2.
Label all connections to the carburetor such as: fuel line, PCV vacuum, and spark - distributor vacuum.
3.
After labeling all connections to the carburetor, carefully disconnect all hoses and lines. When removing the fuel line, slide a rubber cap
plug over the end to prevent fuel from running out, which may create a fire hazard. Use a clean metal container to collect any spilled fuel.
DANGER! DO NOT SMOKE WHEN WORKING AROUND GASOLINE OR GASOLINE VAPORS. EXTINGUISH ALL OPEN FLAMES. AN
OPEN FLAME, SPARK, AND/OR EXTREME HEAT COULD RESULT IN A FIRE AND/OR EXPLOSION CAUSING SERIOUS
INJURY, DEATH, AND/OR PROPERTY DAMAGE.
4.
Remove the throttle linkage and automatic transmission controls from the throttle lever. Disassemble and save the throttle return spring.
5.
Remove the two front and two rear attaching manifold flange nuts. Remove the throttle cable bracket, if so equipped, (located at the right
rear attaching bolt). Remove the carburetor by lifting it straight upward. Sometimes the carburetor can stick to the manifold gasket,
requiring it to be pried loose. Before prying, double check to make sure all the carburetor attaching bolts and connections have been
removed.
6.
Place clean shop towels or rags into the manifold opening to prevent dirt or debris from entering the engine. Keep exposed ends of
vacuum and fuel lines free from dirt.
WARNING! Failure to cover the intake opening with a clean towel could result in dirt or debris entering the engine. Dirt or debris in
the induction system can cause engine damage, which may necessitate in a complete engine overhaul.
7.
Remove the gasket from the intake. Remove any gasket material that may have adhered to the manifold. DO NOT gouge the intake
manifold sealing surface during removal of old gasket material.
8.
Remove the shop towels from the intake and vacuum out the intake channel to ensure no dirt or debris is left in the intake system. Place a
clean shop towel over the entire intake opening until you are ready to install the new carburetor.
FLUSHING YOUR VEHICLES FUEL LINE:
During fuel line installation, be careful to avoid introducing any dirt particles, which could enter the fuel inlet and jam open the needle and seat
resulting in the carburetor flooding, malfunctioning, and/or possible engine fire. To prevent contamination from entering your new carburetor, the
fuel line must be flushed of rust, dirt, and other debris.
1.
Disconnect the wire that runs from the ignition switch to the positive (+) side of the coil. DO NOT allow this terminal to contact any metal
surfaces causing a ground. Cover the end of the wire terminal with electrical tape.
DANGER! ALLOWING THE END OF THE COIL WIRE TO CONTACT A METAL SURFACE, CAUSING A GROUND, MAY LEAD TO A
SPARK ALLOWING VOLATILE GASOLINE VAPORS TO IGNITE, CAUSING AN EXPLOSION OR FIRE, WHICH MAY RESULT IN
SERIOUS INJURY AND/OR DEATH.
2.
Remove the shop towel placed over the intake manifold before cranking the engine.
WARNING! Failure to remove the shop towel from the intake manifold before cranking may result in the shop towel being sucked into
the engine resulting in serious engine damage.
WARNING! Wear eye protection when performing this step. Failure to wear eye protection can result in gasoline or other
contaminates entering the eye, which could result in permanent eye damage and/or blindness.
3A.
Mechanical Fuel Pump: Place the end of the fuel line in a clean metal container and crank the engine. When approximately 1 pint (16
ounces) of fuel has been flushed, examine the fuel for contamination, i.e. dirt, rust, rubber flakes, etc. Repeat process if necessary, until
the fuel is free of contamination.
3B.
Electric Fuel Pump: Place the end of the fuel line in a clean metal container. Activated the pump by turning on the ignition switch.
When approximately 1 pint (16 ounces) of fuel has been flushed, examine the fuel for contamination, i.e. dirt, rust, rubber flakes, etc.
Repeat process if necessary, until the fuel is free of contamination. The fuel pump may turn off after running for a few seconds. In this
case, turn the ignition switch off and on to cycle the pump and flush the line.
DANGER! DO NOT USE GLASS, STYROFOAM, OR PLASTIC TO CAPTURE FUEL. USE ONLY A CLEAN METAL CONTAINER. FAILURE
TO USE A METAL CONTAINER MAY RESULT IN FUEL SPILLAGE, WHICH COULD CAUSE A FIRE OR EXPLOSION
RESULTING IN SERIOUS INJURY AND/OR DEATH.
DANGER! FLUSH FUEL LINES ONLY IN A WELL-VENTILATED AREA AND AWAY FROM ALL SOURCES OF HEAT OR FLAME.
FAILURE TO FOLLOW THESE INSTRUCTIONS MAY CAUSE GASOLINE VAPORS TO IGNITE, RESULTING IN A FIRE OR
EXPLOSION, WHICH MAY RESULT IN SERIOUS INJURY AND/OR DEATH.
INSTALLATION OF NEW CARBURETOR:
WARNING! Holley Performance Products highly recommends that a quality fuel filter be installed with any replacement carburetor to
catch any dirt that may still remain in the system. Any dirt that may enter the carburetor can cause the carburetor to flood or
malfunction. A carburetor that has a malfunction caused by dirt in the system due to negligence of the owner will void the
warranty.
1.
Install a flange gasket on the manifold. If a spacer is being used the order will be flange gasket, spacer, and another flange gasket over the
manifold stud bolts.
WARNING! The carburetor should be installed directly onto its manifold without an adapter whenever possible. Sometimes an adapter
can create problems with hood clearance, airflow, throttle linkage, fuel line attachment, and/or fuel mixture distribution.
However, if an adapter is required one is available through your Holley distributor under P/N 17-9, which adapts the Model
4500 to AFB- Holley square flange manifolds. Adapter height is 2-1/4 inches.
2.
Place the carburetor in position over the four stud bolts and secure in place. Tighten in a criss cross pattern to 60 in-lbs. Be careful not to
overtighten the nuts.
WARNING! Overtightening the carburetor manifold flange hold-down-nuts may result in a warped or cracked carburetor throttle body.
The carburetor hold down nuts should be tightened down progressively in a criss cross pattern to 60 inch lbs., so that
vacuum leaks are prevented and to avoid causing damage to the throttle body. A carburetor that has been damaged due to
negligence of the owner will void the warranty.
3.
Connect the fuel lines, throttle linkage, and return springs. Operate linkage to assure correct travel by fully opening and closing the throttle
by hand.
4.
Attach all vacuum lines where necessary. Not all model 4500’s have vacuum connections, however some model 4500s are equipped with
two vacuum tubes. The larger tube at the base of the carburetor provides full manifold vacuum at idle. Use this for PCV, power brake, etc.
The smaller tube attached to the metering block is timed spark (vacuum provided anytime after off idle). The distributor is usually attached
here. Plastic “T’s” (available through the Holley Performance Catalog) may be used to complete the installation.
STARTING:
1.
Without operating the throttle, crank the engine. It may take 15 to 30 seconds of cranking to allow the fuel bowls of the carburetor to fill. If
the engine does not start, stop cranking, open and close the throttle twice and crank again, until the engine starts.
WARNING! DO NOT crank the engine for more than 15 seconds at a time. Cranking longer than 15 seconds can overheat the starter,
resulting in premature starter failure.
2.
After starting the engine, check fuel lines and inlet fittings for possible fuel leaks.
WARNING! If any fuel leakage or weeping is detected, shut off the engine immediately, and wipe up any fuel. Locate the source of the
leak and correct before proceeding any further.
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TUNING AND ADJUSTMENT:
Before you begin to tune your carburetor for your particular vehicle, you must get a “FEEL” for your vehicle’s performance, so that any changes
you make (Good or Bad) will be readily apparent. Be patient and make only one change at a time, so that only that change can be fully
analyzed. This cannot be overemphasized, as there are no “short-cuts” to peak performance. Recording each change and the resulting
performance increase or decrease will provide you with a “Handbook” of how vehicle performance is affected by individual carburetor
adjustments. This may be helpful in the future or on other applications.
FUEL LEVEL (Float Level):
Figure 1
Figure 2
The float(s) controls the fuel delivery, however if the float(s) is not properly adjusted a fuel starvation or a flooding affect could result. This
operation is difficult to do accurately on a rough-idling vehicle.
1.
For the mechanical fuel pump, remove coil wire and crank engine over
for 10 seconds to allow fuel bowls to fill. This procedure can prevent a
power valve blow out. Reconnect coil wire when finished. Electric fuel
pumps let the fuel bowls fill in stages by turning the ignition on and
then off. Let fuel pump run for a few seconds at a time. This
procedure can prevent the needle from being forced up at an angle,
not allowing the needle to seat properly.
2.
Remove the sight plug from the fuel bowl.
3.
Start the vehicle.
4.
Loosen the lock screw at the top of the assembly.
5.
Turn the adjusting nut while holding the screw in place, until the fuel
level is at the bottom of the sight plug hole even with the threads. A
slight trickle can be seen at the threads. Turn the adjusting nut
clockwise to lower the fuel level and counter-clockwise to raise the fuel
level.
6.
Tighten the lock screw while holding the adjustment nut.
7.
Replace the sight plug and finger tighten.
8.
Flush the fuel bowl by revving the engine a few times with the transmission in neutral.
9.
Remove the sight plug to confirm your setting. A slight trickle should be seen at the threads. Adjust, if necessary.
Figure 3
10. Replace the sight plug and tighten.
IDLE SPEED SCREW:
The idle speed screw in most cases is the only screw you should adjust. The Idle screw controls the throttle plate position at idle which in turn
raises or lowers the engine rpm by allowing more or less air/fuel mixture into the engine. It does not control the air/fuel mixture. Here are the
proper steps for setting the engines idle speed.
1.
Find the proper idle rpm on the underhood decal of your vehicle. If this decal is not available, find a service manual that references your
vehicle and engine, and find the recommended idle rpm.
2.
Start the engine and allow it to warm up.
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3.
Connect a tachometer, if your vehicle is not so equipped.
4.
Make sure the parking brake is on and the wheels are blocked. Place the automatic transmission in drive or the manual transmission in
neutral.
5.
If the idle speed is slower than recommended, turn the screw clockwise to speed up the rpm. If the idle speed is too fast, turn the idle
screw counter clockwise to slow down. This adjustment should be made to both the primary and secondary screws in equal amounts, so
that the throttle plates are opened the same amount.
Figure 4
Figure 5
IDLE MIXTURE NEEDLES:
Idle mixture needles control the air/fuel mixture at idle. The amount of
air/fuel mixture used at idle is controlled by engine vacuum. So when
tuning the idle mixture, you are actually tuning for best manifold vacuum.
Idle mixture needles are found on the metering blocks. Your carburetor
will have four idle mixture needles, one for each venturi, this is known as
four corner idle. If you change one idle mixture needle, you are required to
change the other idle mixture needles the same amount. Here are the
proper steps for setting the idle mixture needles.
1.
Attach the vacuum gauge to the manifold vacuum port, usually at the
rear of the carburetor and on the throttle body.
2.
Adjust each idle mixture screw the same amount to achieve the
highest possible vacuum reading without increasing the idle speed
screw.
3.
Now that the idle mixture is set, it may be necessary to go back and
reset the idle speed using the idle speed screw. Continue back and
forth between the tuning of the idle mixture needles and idle speed
screws, until little change is noticed in manifold vacuum and idle speed is correct.
Figure 6
ACCELERATOR PUMP:
The accelerator pump’s purpose is to make up for the lag in fuel delivery to enable the engine speed to increase in response to throttle opening.
Differences in vehicle weight, transmissions, and rear axle ratios affect the amount of fuel and the delivery rate that should be provided by the
accelerator pump. This may necessitate the customizing of your accelerator pump to your vehicle and its use.
NOTE: The old saying “if a little is good, a lot is better” does not apply to the proper tuning of the accelerator pump. Your car’s performance
can be just as bad if it receives “too much fuel too soon,” as if it receives “too little fuel too late.”
Two factors that affect the accelerator pump’s delivery is the pump cam and the pump shooter (discharge nozzle). The pump cam determines
the total volume of fuel and affects delivery rate; the pump shooter affects delivery rate and helps determine the duration of the shot.
The pump cams, purchased separately, Holley P/N 20-80 have two operating locations and Holley P/N 20-81 has one operating location. This
provides for several distinct delivery rates. The 20-80 pump cam is designed to give a quick early shot of fuel, but it does not empty the pump.
The 20-81 pump cam design delivers an early fuel shot and continues until the pump empties.
The pump shooters have a number stamped on their casting, which designates the shooter size in thousandths of an inch, i.e., a #25 shooter
has a .025” discharge orifice. The smaller diameter nozzles lengthen the pump shot duration and are used with heavier vehicles or with vehicles
equipped with lower numerical rear axle ratios. Larger diameter nozzles (.035 - .037) shorten the pump shot duration, but deliver a greater initial
volume of fuel. These sizes should be used on applications where engine speed will increase rapidly (vehicles with good power-to-weight
ratios). Best acceleration is achieved when the accelerator pump delivers the lean best power air/fuel ratio to the engine; not when the
maximum volume of fuel is supplied. Keep in mind when tuning an HP Dominator, the secondary accelerator pump must supply fuel for a
sufficient time, so that the secondary main nozzles can “start up” and deliver fuel to the engine after the secondary throttles are opened. If the
4
nozzles do not start by the time the pump shot expires, bogging will result. To apply the information above, follow these steps for tuning the
accelerator pump.
Figure 7
1.
Change pump shooters, until the smallest diameter nozzle, which
provides the crispest response is found.
2.
Then change the pump cams and locations, until the right cam is found
that provides even more response.
3.
Finally, change the pump shooter once again, until the crisp response is
maximized.
NOTE:
4.
Figure 8
If a nozzle size is desired that seems “in between” the nozzle sizes
provided, then the nozzle can be drilled to the desired size by using a
wire drill held in a pin vise.
At this point, there should be no bogs, flat spots, or black smoke
(indicating excessive richness) when accelerating at wide open throttle
from a standing start.
JETTING (MAIN JETS):
Figure 9
Due to varied applications that a universal performance carburetor will work with, no additional tuning jets have been included. However, a few
tips on jetting are provided to help you understand their purpose. Holley’s Quick Change Fuel Bowls P/N 34-24 are recommended, if repeated
changes or experimentation with the main jets will be performed.
1.
Out of the box jetting is extremely close for most applications.
2.
In most cases, it will be unnecessary to increase jet size more than four numbers greater than out of the box jetting. However, exceptions
could arise when the carburetor is mounted on a very large volume, plenum-ram manifold.
3.
Carburetors are calibrated at 70° at sea level. Decrease the jet size one number (approx. .002) for approximately every 2000 ft. increase in
altitude. Increase jet size one number for every 35° drop in temperature.
4.
Holley jets are broached, flowed, and stamped according to flow rate. Never drill jets, this seriously alters flow characteristics. Stamped
numbers are reference flow numbers and DO NOT indicate drill size.
5.
Spark plugs provide the best indication of proper jetting. Allow plugs to cool before jumping to conclusions.
AIR BLEEDS:
Experimenting with air bleeds is not recommended and should only be attempted by an expert carb tuner. Countless hours of testing have been
performed on expensive flow stands to obtain the proper bleed size for a given calibration. It is unlikely that a better air bleed calibration can be
obtained, however the 4500 HP dominators are equipped with removable air bleeds. Here is some basic knowledge of how air bleeds work.
The main or high-speed air bleeds affect the entire range of the main-metering-system. The purpose of the main metering system and main air
bleeds is to emulsify the fuel before entering the discharge nozzle to be outlet into the air stream in the venturi. The fuel/air mixture becomes
leaner as air bleed size is increased. Decreasing the size of the main air bleeds will decrease pressure across the main jet, which in turn will pull
more fuel through the main system creating a richer fuel/air mixture. The main or high speed air bleeds also act as an anti-siphon or siphon
breaker, so fuel does not continue to discharge or dribble into the venturi after airflow is reduced or stopped. At high speeds the fuel/air mixture
must be on the rich side to prevent damage to the engine.
The idle system supplies fuel at idle and low speeds. The idle system requires a richer mixture than at cruise speed. Unless the idle mixture is
richer, a slow and irregular combustion will occur know as a rough idle. Decreasing the idle air bleed size richens the idle mixture by increasing
the pressure drop in the system. Increasing idle air bleed size leans the idle mixture by reducing the pressure drop across the idle air bleeds.
The same conditions can be created by backing out the idle mixture screws, which will increase the pressure across the idle air bleeds, pushing
5
more fuel from the idle well creating a richer fuel/air ratio. The Idle mixture screw is the only adjustment recommended for controlling the idle
fuel/air mixture richness or leanness.
The intermediate idle system (if equipped) is designed to provide extra fuel between idle and the main system operation. As the throttle is
opened past idle transfer slot, the manifold vacuum that was being applied to the idle system is greatly reduced. Because of the large venturi in
these carburetors, air flow is not sufficient enough to start the main system, the intermediate system fills this gap eliminating any flat spots in
transition from idle to wide open throttle. One thing to note about the intermediate system is that it will continue to operate even at wide-open
throttle. This must be considered when tuning the main jets. Since the intermediate system is activated by pressure, changing the air bleeds
will adjust the richness of the fuel/air mixture. Decreasing the intermediate air bleed size richens the intermediate idle mixture by increasing the
pressure drop in the system. Increasing the intermediate air bleed size leans the intermediate idle mixture by reducing the pressure drop across
the intermediate air bleeds.
WARNING! ADJUSTMENT OF THE AIR BLEEDS IS NOT RECOMMENDED. AIR BLEED ADJUSTMENTS SHOULD ONLY BE
PERFORMED BY A COMPETENT MECHANIC WITH A COMPLETE AND THOROUGH KNOWLEDGE OF CARBURETORS,
FUEL SYSTEM AND ENGINE REQUIREMENTS. FAILURE TO FOLLOW THESE RECOMMENDATIONS MAY RESULT IN A
LEAN ENGINE CAUSING SEVERE ENGINE DAMAGE, PROPERTY DAMAGE, SERIOUS INJURY, AND/OR DEATH.
WARNING! AIR BLEED SIZES SHOULD NOT BE ADJUSTED MORE THAN SIX (6) SIZES IN ANY ONE DIRECTION FROM THE ORIGINAL
AIR BLEEDS AS SHIPPED FROM HOLLEY. AIR BLEED ADJUSTMENT BEYOND SIX (6) SIZES COULD RESULT IN A LEAN
ENGINE, CAUSING SEVERE ENGINE DAMAGE, PROPERTY DAMAGE, SERIOUS INJURY, AND/OR DEATH.
NOTE:
See Figure 10 for air bleed locations and identification. It is recommended that all jet sizes be documented before any tuning of the air
bleeds or main jets is started. Below is a chart for recording the jet and air bleed sizes for your 4500 HP Dominator carburetor as
shipped from Holley. Should you adjust the air bleed size or main jet size, this chart will allow the tuner to return the carburetor to the
original jetting. Please place this information in a safe place along with any other documentation for your carburetor.
Figure 10
Main
Idle
PRIMARY JETTING
Intermediate
High Speed
Main
SECONDARY JETTING
Idle
Intermediate
High Speed
GENERAL INFORMATION:
This instruction sheet cannot contain all of the information, which may be desired by some individuals. Further clarification is available in
HOLLEY CARBURETORS, published by H.P. books and available at your Holley distributor P/N 36-73.
1.
An in-line fuel filter should be installed between the fuel pump and the carburetor. Recommended fuel pressure should be set at 7-1/2 psi
maximum, 5 psi minimum. Fuel pressures above 7-1/2 psi can create severe fuel control problems and are not recommended.
2.
Fuel lines should be a minimum of 3/8”. A non-restrictive open element air cleaner, Holley P/N 120-102, can be used with the Model
4500’s.
Copyright © 2001
199R-9786-2
6
Date: 4-03-01
Holley
Performance Products Inc
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