Big Healey S.U. Carburetor & Fuel System Details

Austin-Healey

Tech Data for 100/6 & 3000, Mk 1 – 2- 3

(information from AUSTIN-HEALEY: OWNERS WORKSHOP MANUAL, by Kenneth Ball, Autopress Ltd. 1973)


Dimensions are in inches unless otherwise stated

“A” refers to the 2639 cc engine with 2 port head
“B” refers to the 2912 cc engine 
“C” refers to the 2639 cc engine with 6 port head


While I have tried to be accurate as possible, it is very likely that there are typos and errors on this page.  Please note that no one associated with austin-healeys.com assumes any liability arising from the information presented here.  If you find a mistake, please let me know from the contact page and I will correct it.


 SU CARBURETOR & FUEL SYSTEM DETAILS

Fuel system:    
     Delivery:    
               A   SU electric type HP
               B Mks II and III SU electric type LCS
               Later MkIII SU type AUF 300
     Tank capacity:    
               A and B   12 gallons (54.5 litres)
     Fuel pipe outside diameter:    
               A, B and C   .375 (9.52 mm)
     Maximum flow per hour:    
               B   15 gallons (68.25 litres)
               C   12 1/2 gallons (56 litres)
     Suction head:    
               B   18 (457 mm)
               C   33 (810 mm)
     Delivery head:    
               B and C   48 (1219 mm)
     Cut off pressure:    
               B and C   3.8 lb/sq in (27 kg/sq cm)
Carburetor types:    
     A   Twin SU horizontal H4
     B and C   Twin SU semi-downdraught HD6
     Mark II   Triple SU HS4
     Mark II (series BJ7)   Twin SU HS6
     Mark III   Twin SU HD8
     Needle (normal):    
     A   AJ
     B and C   CV
     Mkll   DJ
     Needle (normal):    
               Mk II (series BJ7)   BC
               Mark III   UH
     Needle (rich):    
               Mark II   DK
               Mk II (series BJ7)   RD
               MkIII   UN
     Needle (weak);    
               B   DH
               Mark II (series BJ7)   TZ
               MkIII   UL
     Jet size:    
               A and B Mks I and II .090 (2.29 mm)
               Mk II (series BJ7) .100 (2.54 mm)
               MkIII .125 (3.18 mm)
     Spring colour code:    
               B  Mk II Red
               MkIII Red and green
               C   Yellow
     Float setting:    
               MkIII   .125 (3.17 mm)
     Venturi:    
               Mk II (series BJ7)   1.75 (44.45 mm)
               MkIII   2 (50.80 mm)
     Air cleaners:    
               A   Twin ‘pancake’ type
               B   Oil wetted

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