Section : Carburettors

replace cd150's with SU HS6 on agt6 mk2

Posted By : Paul Bennett, 05-Aug-2004, 05:35pm

I have a mk2 GT6 with I assume mk3 cd150's & mk3 acc cable & Linkage.

I am thinking of changing them to SU HS6's.

I have done some research and found that you need to fit HS6's from a dolomite sprint as they have shorter dashpots to allow adequate bonnet clearance in a gt6.

Does anybody know if these are the correct version to fit onto a gt6 without doing any bonnet modfications.

I also found that you need adaptor plates to connect them to the original inlet mainfold which can be purchased from Moss.

Does anybody know what linkage you need to connect the 2 carbs and acc cable for a gt6

Many Thanks

Paul

Followups :

replace cd150's with SU HS6 on agt6 mk2

Posted By : David Rumens, 05-Aug-2004, 08:09pm

Paul,

The Dolly Sprint carbs are the correct carbs to fit. They JUST fit under the bonnet.

The linkage you will have to make up ourselve.

The Spitfire cable is the best to use as this can be directly coupled to the throttle linkage. Think of the 1500 Spitfire linkage with the cable connected directly to linkage arm.

The needles should be BAE and the Springs Green if you use full flow air cleaners. If the air cleaners are not full flow types then use Yellow Springs.

Dave
- replace cd150's with SU HS6 on agt6 mk2
  
  Posted By : Tim Bancroft, 06-Aug-2004, 01:11pm
  
  I have ran 1.75SU's from a sprint for years on my mk.2.
  I have fitted a mk3 spit throttle pedal and cable arrangement c/w a quadrant brazed onto the link tube between the carbs. The quad. has a hole through it for the return spring that locates onto a bracket bolted onto the suspension tower. To retain the cable end I have fitted a bracket onto the inlet manifold under the servo take off.
  
  I used the TT adapters, but recently got Jigsaw to gas flow them.
  
  Instead of using free flow filters why not adapt the std. airbox to get cool air into the carbs. Also consider heat shields between the carbs and the inlet manifold.
  These carbs will start to pay dividends when c/w mod.head, camshaft and exhaust manifold.
  Or otherwise why not consider triple 1.5 Su's or Strombergs?
  - replace cd150's with SU HS6 on agt6 mk2
    
    Posted By : James Carruthers, 06-Aug-2004, 01:44pm
    
    1500 Spit throttle pedal is cable... Mk3 is an evil lever system...
    
    James
    - replace cd150's with SU HS6 on agt6 mk2
      
      Posted By : Nigel Gibbins, 06-Aug-2004, 03:09pm
      
      I think what James is trying to say is that the Spit MK3 has a pushrod throttle system. So Tim's must've come from something else... he suggests a 1500 spitfire....
      
      ... hmm why doesn James need a translator all of a sudden ... and more importantly.. why is it me?
      - replace cd150's with SU HS6 on agt6 mk2
        
        Posted By : James Carruthers, 06-Aug-2004, 04:16pm
        
        Why did that need translating? I thought it was most straight forward...
        
        If not, I blame the heat...
        
        James
        
        replace cd150's with SU HS6 on a gt6 mk2
        
        Posted By : Paul Bennett, 18-Aug-2004, 03:43pm
        
        I have now purchased a pair of Dolomite sprint hs6's on a GT6 mk3 inlet mainfold with K & N filters.
        
        Its was stated in a previous message that you need BAE needles & yellow dashpot springs, does anybody know the best
        place to purchase these items if required.
        
        Does anybody know what size bolt is required to plug the servo / emission hole on the inlet mainifold as the SU's seem to
        connect straight to the rocker cover connection.
        
        Also there seems various methods of connecting the throttle cable to the Su's, I currently have a throttle cable & linkage from a
        GT6 MK3, could anybody recommend which cable / linkage should be used and if possible provide a photo.
        
        Many Thanks
        
        Paul
        
        replace cd150's with SU HS6 on a gt6 mk2
        
        Posted By : Van Hamlin, 18-Aug-2004, 05:11pm
        
        Burlen Fuel Systems is a good place to buy needles etc. I would also recommend you buy a service pack for the carbs. This includes new seals which are unleaded-proof. If the pipes to the jets have been unscrewed from the float chambers they often do not reseal properly. You won't know if this has been done or not on a 2nd hand pair of carbs so it is better to be safe.
        I use the needles specified by Triumphtune (BAE sounds familiar but I can't be sure). I believe the springs they specify are the same as standard Sprint. I use 20W50 oil in the dashpots and cable/linkage/pedal from a 1987 Metro.
        The blanking plugs you need for the manifold are probably a BSP thread and should be available from a Triumph breakers or from an little industrial unit selling hydraulics if you have one handy.
        Regards
        Van