Section : Carburettors

Change of carbs

Posted By : Tom Hall, 31-May-2003, 02:39pm

I have a Mk3 Spit on 1 1/4" SU's. I have recently aquired a dolomite 1500 engine complete with 1 1/2" carbs. Now, as my carbs need a overhaul anyway, I decided to fit the larger carbs. The manifold fits fine but the throttle linkages are different. They are the same as a Spit 1500. What needs changing? the whole pedal and cable, or can the old linkages be fitted somehow. Also the manifold has an extra water pipe - a T-piece as opposed to a single pipe, can I simply block up one tube or is there a better way of doing it.

Any advice received gratefully, Tom

Followups :

Change of carbs

Posted By : Josh Bowler, 31-May-2003, 09:56pm

i have come across this myself. you can use the linkage from the old 1 1/4 su's on your new carbs.
or get a pedal from from a later spit and convert to cable. the former option is least hassle
- Change of carbs
  
  Posted By : James Carruthers, 31-May-2003, 11:29pm
  
  On my new Mk3 (got it yesterday... woo hoo) I am getting used to the feel of the throttle pedal... I have to say I sort of prefer my old 1500's cable throttle... not entirely sure why...
  
  As I still have my old 1500 (with squished rear end) - I am considering changing over the HS4's (+K&Ns) and SS exhaust manifold from that to my Mk3... tell us how much of a difference you notice... I will be most interested...
  
  James
  - Change of carbs
    
    Posted By : Barry Huffer, 02-Jun-2003, 12:57pm
    
    Re: the T piece.
    
    I have just done the same carb conversion on my MkIV 1300 where there is a feed into the cylinder head that you switch to the T piece and then fit a blanking plug in the cylinder head.
    
    The blanking plug is a tapered fit, I took the pipe out to get a match for the thread and ended up at a Plumb Center because it is a BSP thread, cost 80p.
    
    Either the Moss or Rimmer parts catalogue has a diagram of the old and new cooling/heater systems that helped me get it right.
  - Change of carbs
    
    Posted By : Tom Hall, 02-Jun-2003, 10:00pm
    
    James,
    I am not sure if my observations would be of much use really. I am putting a full phoenix exhaust system + stage 2 needles +Air Trumpets and of course the new carbs themselves - all for the first time-, so if no difference is noticed I shall be very suprised!
    
    If its any help though, I believe that your engine will benefit from the larger carbs, although the difference will not be huge. I think the more modified the set-up the engine is as a whole, the larger the difference increase will be from the larger carbs.
    
    Oh well good luck,
    
    Tom