Results 1 to 7 of 7

Thread: Rebush SU Carbs Black Magic?

Discuss the Austin Healey Sprite and the MG Midget. Two different but similar cars sometimes referred to collectively as the Spridget.

  1. #1
    Jedi Hopeful 60Bugeye's Avatar
    Join Date
    Nov 2010
    Location
    Bainbridge Island
    Posts
    123
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Rebush SU Carbs Black Magic?

    SU carburetter rebuilds seem like a fairly straightforward thing a DIY shade-tree mechanic could handle. After all, the SU carbs seem mechanically pretty simple.

    In my research it seems that "re-bushing" requires professional "black magic."

    Forgive my ignorance (I just got my Bugeye project ), but what does "re-bushing" really involve?

    Is it THAT difficult to do?

    Does it require special tools or years of experience?

    Perhaps it does; just attempting to understand why.

    Cheers!
    - Chris

    1960 Austin Healey Bugeye Sprite project
    1997 Land Rover Discovery
    2004 Saab 9-3 Linear (Wife's car)

  2. #2
    Luke Skywalker
    Join Date
    Jan 2001
    Location
    Toms River, NJ USA
    Posts
    1,581
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Re: Rebush SU Carbs Black Magic?

    I have rebuilt many SUs over the years and have never found one that needed to be re-bushed. Most will need new throttle shafts which will be obvious as soon as you pull them out. The shafts wear in the carb body. Rarely do the bodies wear.
    I am not saying the bodies do not wear, and larger throttle shafts are available for worn bodies. It is a matter of matching the new larger diameter shafts to the carbs. Any machine shop can do it or anybody with a steady hand and a good drill press can do it at home.

  3. #3
    Yoda glemon's Avatar
    Join Date
    Jun 2007
    Location
    Nebraska, USA
    Posts
    3,450
    Thanks Thanks Given 
    14
    Thanks Thanks Received 
    17
    Thanked in
    17 Posts

    Re: Rebush SU Carbs Black Magic?

    Excellent choice, I noticed you said you didn't know quite where to dive into the big project on another thread, they are pretty straightforward and easy to rebuild, and it is a nice job because you just take them off the car and you can do all the work on a nice table or workbench rather than on your back or whatever for some jobs.

    Take one apart at a time, then you will have the other for reassembly reference.

    There are prerry good exploded diagrams in the manuals, I think you had the Clymers, that is a good manual and reference for your work on the carbs and the rest of the car.

    Oh, yes another reason to take one apart at a time, the pistons and top piston housings a matched sets, often doesn;t work to try to mix and match certain parts from different carbs.

  4. #4
    Great Pumpkin JPSmit's Avatar
    Join Date
    Nov 2004
    Location
    Toronto, ON
    Posts
    18,773
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    60
    Thanked in
    57 Posts

    Re: Rebush SU Carbs Black Magic?

    To be completely correct (and I am pretty sure this is right) HS2 Carbs never had bushing for the shafts, HS4's did. I am fairly certain that you can now get bushings for HS2's but, mostly it refers to spritenuts description - redrilling the body for a larger shaft. there is a description somewhere on these boards (May be the MG forum). I can't usually find stuff like that.
    John-Peter Smit
    1976 MG Midget
    1969 Vauxhall Viva GT
    1958 Fiat Multipla (Barn art)

  5. #5
    Jedi Hopeful 60Bugeye's Avatar
    Join Date
    Nov 2010
    Location
    Bainbridge Island
    Posts
    123
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Re: Rebush SU Carbs Black Magic?

    Quote Originally Posted by glemon
    Excellent choice, I noticed you said you didn't know quite where to dive into the big project on another thread, they are pretty straightforward and easy to rebuild, and it is a nice job because you just take them off the car and you can do all the work on a nice table or workbench rather than on your back or whatever for some jobs.

    Take one apart at a time, then you will have the other for reassembly reference.

    There are prerry good exploded diagrams in the manuals, I think you had the Clymers, that is a good manual and reference for your work on the carbs and the rest of the car.

    Oh, yes another reason to take one apart at a time, the pistons and top piston housings a matched sets, often doesn;t work to try to mix and match certain parts from different carbs.
    Yep, I think this will be a good first sub-project after I go through the lot and photograph everything.

    Also, I have 4 SUs and them are in a box, so will have a lot to practice with.
    - Chris

    1960 Austin Healey Bugeye Sprite project
    1997 Land Rover Discovery
    2004 Saab 9-3 Linear (Wife's car)

  6. #6
    Jedi Hopeful 60Bugeye's Avatar
    Join Date
    Nov 2010
    Location
    Bainbridge Island
    Posts
    123
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Re: Rebush SU Carbs Black Magic?

    Quote Originally Posted by spritenut
    I have rebuilt many SUs over the years and have never found one that needed to be re-bushed. Most will need new throttle shafts which will be obvious as soon as you pull them out. The shafts wear in the carb body. Rarely do the bodies wear.
    I am not saying the bodies do not wear, and larger throttle shafts are available for worn bodies. It is a matter of matching the new larger diameter shafts to the carbs. Any machine shop can do it or anybody with a steady hand and a good drill press can do it at home.
    Good to know that replacing bushings is not necessarily obligatory. Thanks!
    - Chris

    1960 Austin Healey Bugeye Sprite project
    1997 Land Rover Discovery
    2004 Saab 9-3 Linear (Wife's car)

  7. #7
    Jedi Hopeful 60Bugeye's Avatar
    Join Date
    Nov 2010
    Location
    Bainbridge Island
    Posts
    123
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Re: Rebush SU Carbs Black Magic?

    Quote Originally Posted by JPSmit
    To be completely correct (and I am pretty sure this is right) HS2 Carbs never had bushing for the shafts, HS4's did. I am fairly certain that you can now get bushings for HS2's but, mostly it refers to spritenuts description - redrilling the body for a larger shaft. there is a description somewhere on these boards (May be the MG forum). I can't usually find stuff like that.
    I think these are HS2s since they measure 1.25, so this may be a non-issue for me. Thanks!
    - Chris

    1960 Austin Healey Bugeye Sprite project
    1997 Land Rover Discovery
    2004 Saab 9-3 Linear (Wife's car)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •