Hitachi DCH340

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The Hitachi DCH340 series carburetor is larger than the stock Datsun 1200 Hitachi DCH306 carburetor, yet runs smoother and makes more power than a Weber 32/36 Carburetor. They came as standard equipment on mid-to-late 1970s Datsun L-series engine, and Jet Kits for the A12 engine were available. It was first used on 1973 L16 and L18, and on all the L20Bs that followed.

Overview

• Technical article comparing to Weber DGV and Hitachi DAF328 (L16) carburetors

  old articleᴬᴿᶜᴴᴵⱽᴱ

• DCH340 parts diagram
• Tercel Swap DCH340

  "The car has never run better, pulls strong (even with the AC on)"

Most 510s used a Nikki carburetor. But the last North American 510s used Hitachi DCH340, the 1973 model. Most 1973-1980 L-series L18 & L20B used them, like 1978-1981 510, 1977-1979 200SX and pickups.

1980 USA version photos

1980 720 Pickup with L20B

1977-1978 620 Pickup with L20B

Jet Kit for A12 engine
Album 15574

DCH340 retrofitted to A14 Engine
Album 1992

parts breakdown

Airflow

Venturis - total area
Weber 32/36: 26/27 - 1103
DCH340 L18 : 23/30 - 1122
DCH340 L20B: 24/31 - 1208

Jetting

1974 L18 DATSUN 620 TRUCK NORTH AMERICA 
venturis: 23/30
Main jets: 100/170
Air bleeds: 60/60
Slow jets: 45/90
Slow bleeds: 145/100
Slow economizer: 1.8 mm
Power jet: 41
Float level: 23mm

A12 CENTRAL TUNING KIT
venturis: unknown
Main jets: 115 or 117/155
Air bleeds: 60/60
Slow jets: 45/90
Slow bleeds: 140 or 150/100
Slow economizer: 180
Power jet: 48
?: 120

Hitachi Carb Lineage

Hitachi DCx Series

• better venturis than the DAF series it replaced
• vacuum operated secondaries
• Used on Datsuns and 1973-1976 Honda Civic 1200/1250

Models

• DCG286: 28 mm secondary bore - Datsun 1000, A10 engine
• DCA306: 1967-1969 520/521 with J13 engine (large bolt spacing)
• DCG306: 30 mm secondary bore - Datsun 1200, A12 engine, manual choke. Honda Civic.
• DCH306: 30 mm secondary bore - Datsun 1200, A12 engine, auto choke. Also used by A13, A14, A15
• DCR306: 1981-1982 A15, E15, E16
• DCH340: 34 mm secondary bore - Datsun 510, 610, 710, 620, 720. L16, L18
• DCH340 with high-speed enrichment system - L20B engine. Isuzu Chevrolet LUV
• DCR360: 1980 L20B, Z20
• DCR342: 1981 L20B, Z20 California, 1982 CA20 Stanza
• DCH342: 1981 L20B, Z20 non-California
• DCH328: 32 mm secondary bore -
• DCR384: 1983-1986 Z24 engine

DFx Series

• DFP306: 1981-1983 MPG Pulsur, MPG Sentra E15, E16
  • Also Geo 1985-1986 M/T 1.0 liter
• DFC328: 1983 Pulsur, Sentra E15, E16
• DCZ328: 1983 Pulsur, Sentra E15, E16
• DFE2832: 1984-1985 Pulsur, Sentra E15, E16
• DFP384: 1983-1986 Z24 engine

Hitachi DAF series - Solex-style primary venturi

• DAF328 - Most L16
  • Ford Courier
  • Also 1987-1988 Ford Ranger 2.0 (Mazda engine)