BXUV-3 carb details.pdf

Stromberg Carburettor model BXV-2

Stromberg Carburettor model BXV-2 single barrel downdraft, used on L6 engines for 173 cu.in. & 202 cu. in. variation being the size of the Venturi and the Main

Metering jets

Stromberg Carburettor Model BXV- 2 Single Barell Downdraft

Stromberg Carburettor model BXV-2 Single Barrel Downdraft, looking up from the bottom:FLOAT NEEDLE VALVE AND SEAT: Controls the fuel that is admitted

into the float chamber.

Throttle Valve: Controls the quantity of mixture of fuel and air that is admitted into the intake manifold, and thereby governs the speed of the engine. Main Metering JET:

Meters the fuel that is used in the range of normal speed operation. ACCELERATING PUMP CHECK VALVE: Admits fuel into the pump cylinder. also is a drain plug

for the fuel bowl, f

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Stromberg Carburettor Model BXV- 2 Single Barrel Downdraft

IDLE NEEDLE VALVE: Controls the quantity of fuel that is discharged from the primary idle hole at closed throttle,

also mixture ratio. FLOAT NEEDLE VALVE AND SEAT: Controls the fuel that is admitted into the float chamber.

Date: 24/11/05 Owner: Jacks Bedford

Size: 640x480

Full size: 1600x1200

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Main jet and drain plug

Under the Drain Plug is situated the. ACCELERATING PUMP CHECK VALVE: This admits fuel into the pump

cylinder, the Main jet and drain plug: Delivers additional fuel momentarily while accelerating to provide smooth and

rapid acceleration, next to it is the MAIN METERING JET: Meters the fuel that is used in the range of normal speed

operation. The Accelerating Pump behind it delivers additional fuel momentarily while accelerating to provide smooth


Size: 640x480


and rapid acceleration


The Vent Valve

The Vent Valve: Admits atmospheric pressure admits atmospheric pressure to the float chamber when the throttle is

closed. NOTE:Do not attempt to conduct this check unless the accelerator pump stroke adjustment procedure has been


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carried out,the vent valve seting is .60"- .50", make sure that he engine idle is between 480 - 520 rpm, this is important

as its the correct setting for the closed throttle.


Inside the Float Chamber

There on the right, is a small gauze, to filter the fuel before it gets sucked up to the Accerating Pump Check Valve:


Admits fuel into the pump cylinder. as the Accerating Pump By-Pass Jet: Meters the fuel that is used in the range of

normal speed pump discharge, on the left is the Main Metering Valve:Meters the fuel that is used in the range of

normal speed operation. The Accelerating Pump behind it delivers additional fuel momentarily while accelerating to

provide smooth and rapid acceleration

Size: 640x480



Inside the Float Chamber

There on the right, is a small gauze, this to filter the fuel before it gets sucked up to the Accelerating Pump Check

Valve: Admits fuel into the pump cylinder. as the Accelerating Pump By-Pass Jet: Meters the fuel that is used in the

range of normal speed pump discharge, on the left is the Main Metering Valve:Meters the fuel that is used in the range

of normal speed operation. The Accelerating Pump behind it delivers additional fuel momentarily while accelerating to

provide smooth and rapid acceleration


Size: 640x480



The Accelerator Assembly

The Accelerator Assembly laid out


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Lay out of the parts of a Stromberg Carburettor Model BXV- 2 Single Barrel Downdraft

Exploded view of the component, with some details Float Chamber Vent (The Internals): Vents chamber to

atmosphere.

Choke Valve: Restricts the air supplying to enrich mixture for starting and during warm up period.

High Speed Air Bleeder: Meters the air that is bled into main discharge system


Size: 640x480


Idle Tube: Meters the fuel for the idle system.

Accelerator Pump: Delivers additional fuel momentarily while accelerating to provide smooth and rapid acceleration.

Float: Maintains the fuel level in the float chamber at a definite level.

Float Needle Valve and Seat: Controls fuel that is admitted into the float chamber.

Vent Valve: Admits atmospheric pressure to

the float chamber when throttle valve is closed


Stromberg Carburettor Model lay out

lay out of bits for a Stromberg Carburettor Model BXV-2 Single Barrel Downdraft, used on L6 engines for 173 cu.in.

& 202 cu. in. variation being the size of the Venturi and the Main Metering jets


Size: 640x480



The Float Level Setting

the float level can be checked while the engine is running, make sure that the vacuum passage is blocked,(tape over

slotted hole) if you need to adjust the level bend the float arm, be careful doing it, don't forget to remove the tape over

the vacumm passage after the fuel level is set.


Size: 640x480



Lead Balls

Here are 4 Lead Balls used to plug up the holes, after the machinery has been finished with in the production of the

Carburettor. Tip:make sure that the Lead Balls don't work loose or crack, if they look suspicious, then just re tap them

with a small Punch to re spread the lead out to re seal . if they leak air the Carburettor will not perform correctly,


Size: 640x480

Full size: 1280x960


The Vacuum Piston Machine Seat

The under side of the Air Horn Body, this part here is were the Vacuum Power Piston fits, and seals off on The

Vacuum Piston Machine Seat at the bottom of the chamber, it allows extra fuel when required, the action of the piston

works in conjunction withe the vacuum from the manifold and the opening of the throttle, this moves with the help of

the spring on the Piston assemble.


Size: 640x480

Full size: 1280x960

See "Holdenpedia" and search for "Stromberg" for more in depth details by "T" and myself


The Vacuum Piston Assembly

The under side of the Air Horn Body, showing the Vacuum Power Piston Assembly, which consists off a Shaft, Spring

& Piston, the piston fits inside thee small chamber there, and seals off on the machined face seat at the bottom of the


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Full size: 1280x960

chamber

The Piston can be screwed off the shaft, to remove the spring, and seting the depth to suite the chamber by turning the

piston L/R on the shaft.

The piston works off the manifold pressure, when max power or high speed running is required the spring and Piston

assembly which is controlled by the manifold Vacuum, it operates the power jet, When the throttle is closed , a high

manifold Vacuum is present and the Vacuum Power Piston is held up against the tension of the spring, and retains the

Power Jet in a Closed position, then when the throttle is opened the manifold Vacuum is decreased sufficiently, then

the spring on the Piston Assembly, moves the Piston down, allowing the power Jet to feed additional fuel into the main

discharge jet system, Quite a simple solution to an important act,


Working parts inside the Carburettor

Working parts inside the Carburettor,:Jets and Valves etc


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main discharge jet workings


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Diagrammatic view of Variable Main Jet

Diagrammatic view of Variable Main Jet.

(1)main discharge jet, (3) variable main jet in position,(4)the variable main jet,(5)main metering jet,(6)plug housing

union,(7)leather gasket,(8) housing nut for the leather gasket,(9) adjustable needle shaft,

This mod is easy to do, remove the metering plug and fit the Variable main jet in its place, wind the needle back, then

screw it in,then tigthen the gasket housing nut to squeeze up the leather gasket to stop fuel leaking up the needle shaft,


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don't over do it, then wind in needle shaft till it bottoms, then come back about 1 1/2 turns, and fiddle till you have it

right, good luck.


Float System

Float System

The fuel entering the carburettor flows via the Needle and Seat Valve , into the float chamber, there it is kept at a

constant level by the float, the chamber is vented by a passage in the the air horn and the proportion of air and fuel

mixture remains substantially the same, further venting is achieved by incorporating an adjustable spring- loaded type

valve, in the horn assembly, throttle opening permits the valve to remain closed. however, when the throttle is returned

to the idle position, the machined end of the accelerator pump plunger contacts the stem of the valve assemble and

forces the valve off its seat, so this ensures positive atmospheric ventilation of the float chamber during engine idle.

Needle and Seat Valve


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Full size: 1017x842


Idle System First Stage

At idle speed (480-520 rpm)the throttle is held slightly open by the throttle Stop screw, by turning it will increase air

flow to the engine and regulate the the engine idle speed, turning the needle vale in weakens the mixture, turning it out


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richens the mixture


Idle System Second Stage Date: 23/04/06

When the throttle valve is open, it uncovers the idle Discharge holes located above the the throttle valve, thus giving

more suction ,so this then delivers more fuel from the Idle Discharge Holes.

Owner: Jacks Bedford

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Full size: 1002x854


Main Metering System

The Main Metering System controls the flow of fuel during the intermediate, fuel flows through the Main Metering Jet

and enters the base of the that jet, it's then by-passes through the two Small Drilling's in the lower square section of the


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jet, and there it flows up the tubular section of the jet. The velocity of the carburetor throat draws the fuel up the Main

Discharge Jet, it's then mixed with the air coming in through the High Speed Air Bleed ,and this mixture is then

discharged down the throat of the carby. One of the features of this set up, is that the fuel vapor bubbles which forms

in a hot carburetor, follow the outside channel around the main discharge jet, there it collects and condense in the

dome-shaped high speed air bleed, there by Percolation is eliminated


Accelerating System Date: 24/03/06 Owner: Jacks Bedford

Accelerating System

To obtain a smooth and rapid acceleration, momentarily, the Accelerating Pump is directly connected to the throttle,

when closed the Accelerating Pump Piston is drawn upwards, and draws fuel from the float chamber via the Inlet

Check Valve into the pump cylinder, when throttle is open, the Accelerating Pump Piston moves down, this creates a

pressure and closes the Inlet Check Valve. and discharges a metered quantity of fuel through the discharge jet, the

pump duration provides a a follow-up action, so that the discharge carries on a over a period

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Full size: 911x878


Power System

Power System

For maximum power or high speed running you need a richer mixture, than at normal opening, the Piston and Spring

assemble is controlled by the , operates the Power Jet, when the throttle is closed, then a high vacuum is present, thus

the Power Piston assemble is held up against the , when the throttle is open to a point were the vacuum has decreased

sufficiently, the spring on the piston assembly move the piston down, thereby allowing the power jet to feed addition

fuel into the Main Discharge Jet System


Size: 640x601

Full size: 912x856


Choke System

Choke System, when starting a cold engine richer mixture is required, the increase in fuel to air ratio is done by

closing the Choke Valve, this shuts off the entry of air into the carbby, when the engine fires slowly open the the

valve, when the engine is hot the valve must be fully opened gain for even running of the engine


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Full size: 985x888


Diagrammatic View Date: 28/03/06 Owner: Jacks Bedford

Diagrammatic View showing what's what and a brief description of the workings.

The original diagram was done by "T" and taken from the "Holdenpedia" section on Stromberg Carburettor,for more

information <a href="

http://gallery.oldholden.com/Jack_s/Stromberg+Carburettor+model+BXV-2/ Jacks sheds "></>here</a>

Size: 640x450

Full size: 1207x849

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BXUV-3 carb details.pdf

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