Old Buick Carburetors : BUICK MODELS 50 60 70 90 1941Previous | Home | Next |
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Form 6469A—Canadian
BUICK 490S-491S-509S-510S
January, 1941
Reprinted June, 1944
MOTOR NUMBERS
"50"—54075704 and up "60"—64085001 and up "70"—74085003
and up
CAR NUMBERS
"50"—1 3880525 and up
"60"—I3880493 and up
"70"—I3880494 and up
(U. S. Production)
491S-5105 (Rear) 490S-509S (Front)
BUICK MODELS 50 60 70 90 1941
Imported and Tourist
Cars Only
(Compound Carburetion Optional on Model "40")
Casting Number on Face of Flange: 4905, 509S—324; 4915, 510S—346.
COMPOUND WCD DUAL DOWNDRAFT CARBURETERS
Model "50"—Front, Climatic Control Carbureter, No. 509S—List
$44.10. Rear, No. 510S—List $23.50
Models "60-70-90"—Front, Climatic Control Carbureter, No. 490S—List
$44.10. Rear, No. 49I S—List $23.50
(Carbureters 509S-510S, Optional Equipment on Model "40")
Exchange Allowance on Nos. 490S and 509S, $10.00; on Nos. 4915 and 510S, $5.00
CARBURETER SPECIFICATIONS
WCD 509S-510S—For "Buick "50" (Optional "40")
8 Cylinder Engine: 3-3/32" Bore, 411/6" Stroke
WCD 490S-49IS—For Buick "60-70-90" 8 Cylinder Engine: 3-7/16" Bore,
4-5/16” Stroke
Dimensions: (All Models) Flange size, I in. dual, 3 bolt type. (All Models)
Primary venturi, 1 1 /32 inch I. D. (490S-491S) Secondary venturi, 21 /32 inch
I. D. (4905-491 S) Main venturi, 1-1/16 inch I. D.
(509S-510S) Main venturi, 7/8 inch I. D.
Float Level: (All Models) Distance from seam of float (both sides—at
top center) to lower edge of bowl cover, when needle is seated, to be (early
production) 9/64 inch; (late production) 3/ 16 inch.
Vents: (4905-5095) Inside (balance vent tube) 7/32 inch inside diameter.
Gasoline Intake: (All Models) Square vertical needle. Size No. 42 drill hole
in needle seat.
Gas Line Connection: (All Models) 5/ 16 inch Weather-head elbow.
Low Speed Jet Tube: (All Models) Jet size, No. 70 drill. By-pass, size No.
55 drill.
Economizer, size No. 65 drill.
Idle bleed (Early Production), size No. 56 drill; (Late Production), 58 drill.
Idle Ports: (All Models) Upper port, slot type, lengths, .100 inch. Width,
.030 inch.
Idle Port Opening: All Models) .067 to .073 inch above upper edge of valve
with valve closed tight.
Lower Port: (For Idle Adjustment Screw) (All Models) Size .0615 to .0655 inch
diameter.
Set Idle Adjustment Screw: (All Models) 1/4 to 11/4 turns open. For richer
mixture turn screw out. Do not at-tempt to idle engine below 8 m.p.h.
Vacuum Spark Port: (490S-509S) .065 to .067 inch diam-
eter. Bottom of port .035 to .039 inch above valve.
(SEE PAGE 4 FORMain Nozzle: (All Models) In primary venturi, closed tip angle
40° from horizontal. Nozzle installed permanently. Do not remove.
Metering Rod: (Vacumeter Type) (4905) Economy step .0675 inch diameter. Middle
step tapers to .063 inch diameter. Power step .054 inch diameter. Length 3-9/64
inches.
(509S Economy step .072 inch diameter. Middle step .070 inch diameter. Power
step .060 inch diameter. Length 3-9/64 inches. This rod is designed with idle
stabilizing flat on economy step.
Metering Rod Jet: (490S-509S) .086 inch diameter.
Metering Jet: (491S) .053 I inch (1.35 mm) diameter. (5105) .0492 inch (1.25
mm) diameter.
Metering Rod Setting: (490S-509S) Use gauge, Part No. T 109-152 (2.440 inches).
Accelerating Pump: (490S-5095) High pressure type (spring operated lever).
Discharge jet (twin) size, No. 73 drill.
Relief passage to outside, through slots in bowl cover. Intake ball check size,
No. 40 drill.
Discharge (needle seat) size, No. 50 drill.
Pump Adjustment: (490S-509S) 21 /64 inch (8.33 mm) plunger travel (full throttle
position). Use gauge No. TI09-I17S.
Choke: Climatic Control, set at index, butterfly type, off-set valve. Choke
heat suction hole in bowl cover. (490S) Size, No. 36 (.1065 inch) drill. (509S)
Size, No. 40 (.098 inch) drill.
MOTOR TUNE-UP)