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Another silly Carb Question [piston spring?!?!?!]

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martyc

martyc

Jedi Hopeful
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Hmmmm...When I rebuilt my '52 TD carbs recently, there were no "piston springs" in them. The carb rebuild video that I used as a reference said that some carbs do not have piston springs (didn't mention which), so I just figured that my '52 didn't use piston springs. /ubbthreads/images/graemlins/thumbsup.gif

Anyway, I was browsing my local MG club's tech tips site this evening and found that there is a piston spring number (AUC4587) listed for the 1952 carb. See:

https://www.keystonemg.com/tech/carbs-year.html

/ubbthreads/images/graemlins/eek.gif Does this mean that there should be piston springs in my carbs? I'd hate to leave out a critical component since I've gone through the trouble of rebuilding them. And I'd rather get the springs in now if they're needed (while the carbs are on the bench).

Thanks for any insight!

Marty
 
Some guys remove the springs to quicken throttle response.It also slightly effects the piston height, thus the airflow and mixture, during operation. You can do the rebuild without them, they are easy enough to put in later. Test drive it and if it seems to stumble on takeoff no matter how much you adjust the carbs then add the springs (and you can play with the weight of oil in the dashpots).
I bet there is a TD guy in here somewhere that can give you a better answer. this is more of a general SU thing.
 
Depends on the carb. Early SUs had heavy pistons and no springs. The large diameter of the piston on the early springless kind is solid. Later models are recessed - like a bowl.
 
[ QUOTE ]
Depends on the carb. Early SUs had heavy pistons and no springs. The large diameter of the piston on the early springless kind is solid. Later models are recessed - like a bowl.

[/ QUOTE ]

My pistons are solid, not recessed. Thanks!
 
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