> "Carl Musson wrote
> Subject: TR3/4 Carbs
>
>
> My 3 has a '4 engine in it (about ct39000)
> I am going to rebuild a set of carbs over the winter, and wonder
> 1) which is standard for that motor (SU or Zeniths)
> 2) which gives better performance (SU or Zeniths)
> 3) which is easier to maintain
> 4) which is easier to rebuild
>
>- '58 TR3A
Carl,
Firstly don't dispair that you have the TR4 engine inside your TR3 ,
there is no real difference in the block other than for the TR4 block
having 87mm size pistons & sleeves and a breather cap over the breather
hole near the bottom left rear of the motor (which can easily be punched
out if you ever overhaul the motor).
My advice about the carbs.... Go with the 1 3/4" HSU's which were
original on the car. They are also about the simplest carb ever made and
require no maintenance unless they ever gum up.
As for rebuilding get yourself the Haynes "owners workshop manual" for
SU carburators. It's very detailed and easy to follow even for a
relative novice. The HSU carb only has two adjustments to it, the
throttle screw and the jet nut which raises or lowers the height of the
jet. The closest thing you can compare the SU's to is a toilet bowl, the
fuel bowl fills up and the fuel "flushes" through the carb, with the jet
needle, piston and throttle disk adjusting the air/fuel mix. The thing
to watch out for is air leaks which are caused by worn throttle bushings
and deep scratches on the piston chambers which will impead performance.
Buy yourself a proper overhaul kit and it's probably a good idea to
change your needle, jet, and float needle once your overhauling. If the
throttle bushings are worn you'll have to order a new throttleshaft &
bushing kit.
As for performance, most will swear by these carbs.
Good Luck
Barry Shefner
59 TR3A OTS 57675
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