SU HIF44 Questions

[ToolsnTrack]

Planning on hooking this onto my Vitara. I have a couple of things i need to clear up though...



I have a choke cam, but no hole in the casting for the choke cable (circled). Is this normal? Why is it missing?

Next up:



Am i right in thinking that...

1: Fuel in?
2: vacuum line? (but what vac?)
3: Fuel overflow?

[chairchild]

1: fuel in,
2: breather pipe connection (or most likely, just blocked off )
3: fuel overflow

If the choke connection isn't drilled, then it instead used an external bracket to hold the choke cable. Technically, it's better, as it's further away, meaning less bending on the cable. Really simple thing to make

www.plminishop.com/Carburetor/Fuel_Parts/977/CARB_HIF44_ABUTMENT_BRACKET.html

[ToolsnTrack]

Oh, i have one of those! I assumed that bracket was my throttle cable holder....

Hmm, where does the throttle cable go now....

[ToolsnTrack]

Also, that needle like barb to the above right of "2" in the second picture? That i deduced to be vac advance, but it looks to be pre throttle butterfly which would make it useless. Whats it for?

[sowen]

The throttle plate sits at an angle when closed so the small needle like port you're referring to is on the engine side of the throttle for the vacuum advance

[jrevillug]

Yeah, it's the vac advance take off.

That's what's called "ported vacuum" - the throttle shuts off the vac take-off at idle, which means that the engine burns the fuel a little less efficiently. Sounds like a bad thing, but allows the engine to warm up more quickly and maintain temperature in slow-speed cold conditions. So you can put the choke in sooner, and save fuel overall.

Some cars do run the vac advance straight from the manifold - AFAIK these mostly live in warmer areas and have bigger engines. Mercedes have used a temperature-controlled valve to shut off the vac advance entirely when the engine's cold.

[ToolsnTrack]

Interesting! I never looked into it with that much depth, but it makes sense. Cheers for the input!

[Ryannn]

That bracket shouldn't be drilled. I've got a HIF44 on my mini if you want me to take some photos of one "in situ"?

[ToolsnTrack]

Would certainly help if u don't mind?

[Ryannn]

The breather on a mini goes to the crank case breather pipes, it brings oily air into the carb



I struggled to get a good photo of the linkage side, my mini has no battery atm! lol



Basically the cables are on external brackets, front one is accel and the rear one is choke. The vacuum on mine is disconnected at the moment, but it goes to the dizzy.



Any good?

[ToolsnTrack]

I don't have my carb at hand, but I reckon that covers every base! It run ok with the vac advance port open to atmosphere like that?

Cheers for uploading, that's a massive help!

[Ryannn]

It runs fine yeah, tbh, I havnt had it running to the dizzy in over a year, I've usually got it plumbed into a vacuum dial on the dash.

[chairchild]

it'll run a bit lean (as it IS a leak) but on a well-running engine that's already setup, it shouldn't cause much more than a slightly lean running condition.


Obviously, not ideal though.

[Ryannn]

You can run them with a bit of rubber pipe on and a screw in

[ToolsnTrack]

So i got the neccesary needle to run my application, but the curse word is too large to fit in the jet.



Do certain needles need specific jets? I was sure it was only the needles that varied...

[jrevillug]

There are a couple of different jet sizes - 0.090" and 0.100" ring a bell.

[vitesseefi]

According to my Haynes SU book there are 3 jet sizes in the SU family. 0.09", 0.1" and 0.125". They need to have matching needles.

The HIF carb series only uses 0.09" and 0.1" so don't go buying 0.125" needles for it! If you know the needle code letters I should be able to tell you what size jet it needs. If you know what car you carb came from I can also tell you what size jet and which needle it was born with. Also what spring it had fitted - there are 3 or 4 different spring weights fitted (and two different diameters) and this also matters as the spring weight also affects the fueling profile.

Cheers

Nick

[ToolsnTrack]

Cant remember the needle code (it was A something) but the needle I've been recommended is a BDL. Would this be a radical departure?

Also, i do know i need a yellow top spring too, this will be ordered at some point.

[ToolsnTrack]

Like this then?

cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=251197632009&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en

[jrevillug]

Yeah. BDL is for a 0.100" jet.