Dellorto

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Dell'Orto carburetors from Italy their DLHA series were fitted to the Datsun 1200 SSS model. Dellorto made other types, but the DHLA fit the common Weber DCOE carburetor intake manifolds.

Overview

Dellorto DHLA are similar to the Weber DCOE carburetors, but have their own unique parts and some say a better design and look better.

http://www.dellorto.com

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The DHLA & DRLA carburettors are widely believed to be the most sophisticated carburettors of their type, prompting David Vizzard to say in Auto Performance magazine, “Dell’Ortos produce truly excellent results...On engines where atomisation is a premium requirement, Dell’Ortos are superior to everything”.

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The last Dellortos were made for the Lotus Esprit Turbo. Production ceased in 1992 due to lowered demand for carburetors in the face of EFI.

Source

Dellorto DHLA may be purchased from Eurocarb at http://www.dellorto.com

Selection

As with any carburetor, the single most important specification is the venturi (choke) size -- not the barrell size. So a 40 or 45 is not the question. The question is which choke size should be used.

See main article: Carburetor Sizing

For a stock A12, 28 mm is the correct choke size. Which the DHLA series, you can use either 40s or 45s -- a wide variety of venturis are available for both.

Tuning

Tuning any carburetor is mythically difficulat. However, DHLA is no more complicated than Weber or the Hitachis that come stock on Datsuns. They are tuned basically the same way.

SSS DHLA40 jetting specs
Venturi: 28mm
Main jet: 115
Needle and seat: 1.50
Float: .01
Starter jet: 70
Starter emulsion tube: .01
Idle jet holder: .01
Idle jet: 50
Air corrector: 200
Emulsion tube: .01
Aux venturi: .01
Pump jet: 33
Pump delivery: 7.5

To suit SSS A12 engine with mild rally cam (see specs in SSS section) and 4-2-1 tubular headers

Also see: http://www.gruntled.com/Dellorto/

NOTE: When removing and re-inserting the Pump Jet, be sure to line up the passages. See http://www.gruntled.com/Dellorto/PumpJet.html

1. Choose DHLA 40 for A-series engines
   1. Or DHLA 45 for larger engines
2. Choose appropriate venturi size, perhaps 26mm is best for stock A12 engine
   • Available from 25 mm to 37 mm in increments of 1mm
   • Part number 8383.25 to 8383.37 at Eurocarb
   1. Auxiliary venturi from size 1 to 4
3. DHLA Starter -- tuning for cold starting
   1. starter jet sizes from 48 (3315.48) to 105 (3315.105)
   2. starter emulsion tube 1 to 4 (7482.1 to 7482.4)
4. Accelerator Pump
   1. Pump Jet sizes 33 to 60
   2. Pump rod adjustment. Screwing the nut tighter increases fuel delivery, turning it anti-clockwise reduces delivery.
      • Combination of Jet and tightness works 1) Time, shoot for 1 second 2) volume. Probably twin carbs will be within 1/2 turn of each other to deliver the same volume. Test this by actual measurement using a CC vial.