> I have decided to rebuild the SUs on my 60 TR3A over Christmas, as I
> am getting a little dampness in the area of the adjusting nut. I
> have not rebuilt SUs since the mid-70's when I rebuilt the H6's on my
> 58 MGA. I have ordered the rebuild kit from Moss & still have my
> copy of Tuning S.U. Carburetters (Speedsport, 1972).
>
> As I remember it, it was not a complex task. But I am looking for
> any words of advice or paths that should not be followed?
As long as you're not disturbing the throttle shafts, the rest of the
rebuild is straight forward. "Dampness in the area of the adjusting nut"
usually just means the jet seals are shot ... I find that the "high tech"
seals sold by Moss (which are just standard size O-rings, probably nitrile
rubber) last significantly longer in daily use than the replacement cork
seals do. (Don't know why, but replacement cork seems to be much lower
quality than original cork.)
One thing to look for while they're apart is wear in the piston shaft. If
light finger pressure will cause the piston to drag on the sides of the
cylinder walls (even just the sound of dragging) then you should find &
rectify the problem. Also check for any damage or high spots on both the
piston and the walls.
If you don't know how long it's been since they were rebuilt before, I would
suggest replacing the jets, needles, springs inside the jet housing and the
jet return springs. Not all of these parts are included in the rebuild
kits. (ISTR the "Master kit" has the jets but not the springs, while the
lesser kits don't have the jets either.) In theory the jets & needles will
never wear, but if the engine has been driven with the jets improperly
centered, the resulting wear in the jet will upset the mixture. But if you
know everything was fine before and it's just the jet seals are weeping,
then just replace the seals.
Randall
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