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Re: carb differences?

To: "Bud Krueger" <>, "derfman" <>
Subject: Re: carb differences?
From: "Paul Hunt" <>
Date: Mon, 6 Dec 1999 08:31:18 -0000
HIFs are 'later' i.e. in theory they should be 'better' but a lot of the
changes were for emissions reasons which may affect performance.  The
throttle butterflies have those pesky overrun valves that can cause problems
with high idle speeds - but they can be soldered shut or the butterflies
replaced with plain ones.  It's a dismantle job to replace the HIF jets as
they are inside the float chamber.  The float chamber on the HIF has its
'lid' on the bottom hence the seal is below the surface of the fuel and can
leak, and again it is a remove and dismantle job to replace the float
valves.  One of the beauties of the HS is its simplicity, whereas the HIF
has a bypass jet and a choke jet in addition to the main jet - i.e.
potentially more to get blocked or otherwise go wrong.  You can't see what
the choke is doing on an HIF.  And in these days of emissions police you
could potentially run the with the HS jets held in a slightly lowered
position by a control separate to the choke for maximum performance, then
raise them if stopped by a roadside check to the 'ecology' position.  With
the HIF you can only alter the mixture with the mixture screw (much more
tricky to adjust from inside the car) or the choke - which would include
fast-idle but also richens progressively less as the throttle is opened,
unlike the HS choke.


----- Original Message -----
From: Bud Krueger <>
To: derfman <>
Cc: <>; MG List <>
Sent: Monday, December 06, 1999 12:20 AM
Subject: Re: carb differences?

> Hi Derf,
>       There is indeed another list that is predominately MGB but also has
> large contingent of MGA, Midget and T-series members.  Its called the
> list.  I seem to recall that this Spridgets list is a spinoff from a
couple of
> years ago.  I'm really a lurker from that list.  A friend asked me to find
a RB
> Midget for her and I'm just trying to bone up on such machines.
>      Hope you don't mind, but I'm going to forward your letter to the mgs
> where there are a number of knowledgeable folks who have discussed this
issue in
> the past.
> Bud Krueger
> 52TD
> 77MGB
> derfman wrote:
> > Hi,
> > Anyone on the list care to comment on the pros/cons or attributes of HIF
> > type carbs versus HS types?  This may be a question for the MGB list, if
> > there is one.
> > Cheers,
> > Derf

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