mgs
[Top] [All Lists]

HIF Throttle Shafts/Plates Leakage & Alignment

To: <ptegler@cablespeed.com>, "MG Digest (E-mail)" <mgs@autox.team.net>
Subject: HIF Throttle Shafts/Plates Leakage & Alignment
From: "Christian, Skip" <wellner.christian@navy.mil>
Date: Wed, 14 Apr 2004 09:48:23 -0400
Paul,

        Being an engineer, I'm embarrassed to say I don't completely understand 
what
you're saying below.  By "offset in the throttle plate", I assume you mean
that the plate to bushing distance is greater on one side.  Assuming no wear
in the bushing, I do not see how the throttle plate would be pulled to one
side - or is this a problem only when shaft/bushing wear is present ?  Does
this get bad enough that if there is leakage because of a misaligned plate, I
could see it without removing the carb(s) (using a mirror) ??
        I don't see how the grease would pull the throttle plate off to the 
side (or
even up).  The grease is filling the cavity formed by the outside of the seal
and the end of the carb body.  It is wiped smooth with the carb body and does
not come in contact with the linkage.
        I agree that if air was leaking in from the shaft end(s), the idle 
would be
lean.  On top of that, any air leaking from the air cleaner side of the shaft
shouldn't effect idle mixture or idle speed.
        For the plate alignment procedure you mention below, it would make 
sense to
me to do this with the linkage attached if it is the linkage that is pulling
the plate out of alignment.  Normally, I wouldn't think of trying to center a
throttle plate with the linkage attached (too delicate a procedure, too high a
risk of carb bore damage), but with these carbs, it seems like the right thing
to do.  What do you think ??

Thanks,  Skip
'74  MGB (still idling slow with the grease, not many miles though)


I've always found you really don't need to add a seal on the lever
side.  Since the real problem is an offset in the throttle plate
position on axis, as the shafts are what wear, the throttle
plates don't line up properly to seal the throttle bore.
So if you pack the lever side, you'll be pulling the throttle
disk up against the side wall of the throat, thus accelerating
the problem or air leaks as the butterfly digs into the wall
further adding to the air leak space.
Simply loosen the two screws holding the throttle disk, don't
remove just loosen.
Now turn your throttle shaft while repositioning the disk
to perfectly and completely seal the throttle bore.
Now snug the lever up against the body of the carb
and tighten the screws. With  the lever tight against the body
any rotary motion of the butterfly will only opens up a bit
of slop, but closed, and the lever against the body, the
butter fly will snug up to stop leaks when idling.





<Prev in Thread] Current Thread [Next in Thread>
  • HIF Throttle Shafts/Plates Leakage & Alignment, Christian, Skip <=