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SU HIF38 Plumbing/Pipes Diagram
Posted: Fri Oct 24, 2025 11:10 am
by svenedin
A diagram of the various pipe connections to the SU HIF38 carburettor courtesy of Declan Burns. This diagram is referenced but lost from many old threads on this forum.
As I understand it, there are left and right versions of HIF38s with the version with most connections opposite the exhaust downpipe being more desirable in a Minor.
Stephen
- HIF38 Vacuum advance.jpg.jpeg (356.19 KiB) Viewed 2356 times
- HIF38_plumbing_GB.jpg.jpeg (105.57 KiB) Viewed 2356 times
Re: SU HIF38 Plumbing/Pipes Diagram
Posted: Sat Oct 25, 2025 8:02 am
by Sleeper
Would help knowing what open/extended, A , B are?
John ;-)
Re: SU HIF38 Plumbing/Pipes Diagram
Posted: Sat Oct 25, 2025 8:19 am
by svenedin
The tube labelled open/extended is an overflow from the float chamber so it can be left open as a breather or extended with a drain pipe.
A and B are some kind of economy system that weakens the fuel mixture at constant motorway speeds.
Stephen
Re: SU HIF38 Plumbing/Pipes Diagram
Posted: Sat Oct 25, 2025 11:12 am
by Sleeper
I think B (A in red ) is the distributer vacuum advance
John ;-)
Re: SU HIF38 Plumbing/Pipes Diagram
Posted: Sat Oct 25, 2025 11:54 am
by panky
The inlet elbow can be kept as the Mini air box will fit with a simple modification. The vac advance port is shown in the first picture
Re: SU HIF38 Plumbing/Pipes Diagram
Posted: Sat Oct 25, 2025 12:18 pm
by svenedin
Sleeper wrote: ↑Sat Oct 25, 2025 11:12 am
I think B (A in red ) is the distributer vacuum advance
John ;-)
That's on the first picture on the top.
Stephen
Re: SU HIF38 Plumbing/Pipes Diagram
Posted: Sat Oct 25, 2025 5:01 pm
by Sleeper
Yes.
John ;-)