Well, I don't think I'm confused on whether they are HIFs or HSs. Only the
HIFs can leak from the float chamber cover as the seal is perpetually below
fuel level, of course. On HSs it is above fuel level and so highly unlikely
to leak, except possibly in Australia :o)
I've never used them but I have heard enough bad things about Grose jets
(never understood why they are called 'jets' and not valves, which is what
they are) to say that if you don't have them but the original needle valve
and they are not leaking then leave them alone. Even when replacing mine
I've stayed with the needle valves.
I don't know if GKs make a difference but the UK always had the high
compression engine with both HS and HIF carbs. For the UK these were always
AUD616 with AAU needles. For North America there were AUD493 with AAU
needles, then AUD550 with ABD needles, but Clausager says the changes were
minimal. Looking at the profiles there is a 0.4% difference at station 4,
1.9% at station 5 and 0.7% at station 6, the AAU being the richer of the
two, otherwise they are identical. The AAL has a similar *richening* in
that area, but a marked weakening starting from station 7 and going up to
25% at station 16.
PaulH.
----- Original Message -----
From: "d williford" <williford@verizonmail.com>
To: <mgs@Autox.Team.Net>
Sent: Tuesday, October 05, 2004 3:47 AM
Subject: "Upgraded" carb needle question
> This 71 is not fitted with twin HS4 carbs as standard, but 72-spec HIF
carbs (AUD 493s). The carbs appear to be in excellent shape, however, the
front (left) carb is leaking from the float bowl, prompting at the very
least removal and replacement of the cover plate sealing ring. While inside,
I suppose I should at least confirm fitting of Grose jets and proper
functioning of the carb internals.
>
> Heres the question 72 carbs spec an AAU needle Will this affect
performance on a higher-compression 18GK engine (8.8:1 vs. 8.0:1 on 18V
engines)? The original 71 HS4s spec an AAL needle. Are there any issues
that I need to be aware of regarding this upgrade to the carburetors
(carburetters) that may affect performance and/or reliability?
Check out the new British Cars Forum:
http://www.team.net/the-local/tiki-view_forum.php?forumId=8
|