SU HIFF44 carb fit - with heated manifold adaptor

Nigel Head · Last edited by Nigel Head on Fri Apr 17, 2009 11:40 am; edited 3 times in total

This article is for conversion to fit a Vitara 1600 8v engine - 1300 is similar, see the link at the bottom of page 2

First, take one slightly shop soiled SU HIF44.
Ignore the muck, the throttle & choke spindles were a nice fit with no detectable sideways slop.

Pic1

Give it a really good clean up with petrol or carb cleaner and a tooth/paint brush.

I drill a new hole for the vacuum take off point to breakout on the air filter side of the brass butterfly and blank off the old take off point.
Look here for reference:
http://archive.difflock.com/discus/messages/8/66358.html?1108236668
http://archive.difflock.com/discus/messages/8/68036.html

Pic2

Strip it right down to individual components and rebuild with new gaskets/seals as appropriate. I got mine from Burlen Fuel Systems www.burlen.co.uk
If building for a 1300 engine a BDL needle works well, if it's for a 1600 Vitara, then a BFM is recommended. I've rebuilt mine with a yellow spring, which is slightly stronger than the standard red spring.

Pic3

New rubber seal on the float chamber, these tend to harden with age and not worth rebuilding with an old one as it will probably weep at the best.

Pic4

Damper, needle/bushing assembly

****

Damper, spring, carb assembly

Pic6

Don't forget the C shaped spring clip if you have an SU with bearing damper piston

Pic7

Standard 1300 manifold (cutting out the 2 holes)

Pic8

This manifold is a 1300 single point injection one

Pic9

Cut out the manifold to suit the single inlet of the SU (1600 8v Vitara manifold)

Pic10

More follows...

Nigel Head · Posted: Sat Nov 10, 2007 6:51 pm Post subject:

Here is where I detract from the normal adaptor plate.

On my Vit manifold there is a waterway that is used to flow coolant from the manifold up around the original Aisin carb and back out via a small rubber tube back to the water pump (it's pretty much the same for the 1300).
It's circled in red on the pic of the Vit manifold above (Pic10).
So, knowing the SU carb icing issues, I decided to make a little water jacket around the adaptor. Feed it from the manifold/adaptor and back out via the original tubing.
I don't think I've ever seen an adaptor made in quite this way before.
I've seen a jacket fed with 2 water pipes but not with just one pipe and the other feed from the manifold itself, which will allow normal water flow throughout the manifold, as original.

I made a jacket from a scrap of box section, drilled a couple of holes to allow water flow. I used an offcut of quarter inch brake hose to the adapter and 8mm for the original hose that normally gets capped off or short-circuited. Also capped the jacket and welded it on to the adapter, welded the 8mm connector and soft soldered the brake hose.

Pic11

Pic12

Pic13

Made a gasket to suit the adaptor to manifold with additional hole for coolant flow, connected the original water pipe to the hot water jacket 8mm pipe.

Pic14

If you make your own air filter adapter you need to make 2 slots into the inlet itself to allow the piston damper to draw air. This is a must, because with out them, the damper can't rise freely. If using a normal SU air filter connector then there is no need to worry.
I've circled in red the normal air flow passages.

****

Bolt on the SU to the adapter with new gaskets, connect up the throttle cable and choke cable. I bought a longer throttle cable and cut it to suit. Choke is a 'one size fits all' cable from my local auto factor, cut to suit.
Connect the fuel line. I used an inline fuel filter with stepped pipe sizes as it allows easy adaptation from 6mm to 8mm fuel hose sizes as the fuel pump uses 6mm and the SU takes 8mm.
Connect a pipe from the carb to your air filter/snorkel.
I cap off the big pipe on the carb that used to take the feed from the donor cars rocker cover.
Why put dirty air into nice clean air?
I run the original pipe from the Suzuki's rocker cover into the T piece that goes down to the PCV valve and on to the original air filter.
For safety's sake, run a pipe from the float overflow to a point somewhere near the bottom of the engine, the last thing you want is petrol running over anything hot should the float ever jam open.
Top up the damper with SAE20 grade oil (that is what is recommended by Burlen).

Pic16

Pic17

You will need to connect up an air filter any way that you can.
I've deliberately not shown mine as each case will be different, dependant on your own particular circumstance.

Pull the choke out, fire it up and as it gets hotter, progressively put the choke in and then set the mixture!
Don't forget, turning the mixture screw IN on an SU HIF44 makes the mixture RICHER (therefore, undoing it makes it leaner!).

How does it run?
Just fine, and if you've done it right it should fire up for the first time within a few seconds.
Video of mine running:
http://www.youtube.com/watch?v=F2D34y64SN4

The adaptor is nice and hot and so far, no signs of any icing !!!

Enjoy Laughing

I do need to test some more as I only fitted it up today and will aslo try a BDL needle as it is slightly richer than a BFM and on the test drive mine felt a little sluggish on the BFM with yellow spring.

If you are fitting to a 1300 engine, have a read of this as there are subtle but important differences !
http://forum.difflock.com/viewtopic.php?t=31430

Nigel.

Nathaniel · Posted: Sat Nov 10, 2007 6:54 pm Post subject:

Nigel..

Its Beautiful!

*Wipes Tear from eye*

Definately one to go in the sticky! Razz

Nat

jeepmadmike · Posted: Sat Nov 10, 2007 7:02 pm Post subject:

looking good Nigel, will you be down tomorrow for the springs? what was wrong with the asain carb my vit never gave fueling problems at any angle?

Nigel Head · Posted: Sat Nov 10, 2007 7:06 pm Post subject:

Nat,
Good, we regularly see SU questions on the forum, so I thought I would fully document this one.

Mike,
It had a Weber on it, OK on road, stalled every time when going up hill off road.
Won't be able to make it out this weekend, I'll be in touch as soon as I can.

Nigel.

Brettyboy · Posted: Sat Nov 10, 2007 7:29 pm Post subject:

Another excellent job Nigel Wink

Are you comin out next weekend ?

Tramp · Posted: Sat Nov 10, 2007 9:01 pm Post subject:

thank you,

(thought id better post while the printers busy overheating Rolling Eyes

)

luke

*Edit*
will you be making a batch of these to sell to the hopeless (and incompetent) suzuki owners? if you are i would be interested,

twozooks · Posted: Sun Nov 11, 2007 1:14 am Post subject:

Got to ask Embarassed

Having read the 2 threads to vac advance debate. What difference does it make if you have vacuum at idle? Confused

Kitesurf · Posted: Sun Nov 11, 2007 6:27 am Post subject:

Cracking write-up Nigel and what a great idea for the water jacket.

Nat, get it into the sticky at the top of the page.

Nigel Head · Posted: Sun Nov 11, 2007 9:13 am Post subject:

Luke,
Sorry, I don't intend to make any adaptors and sell them.

Twozooks,
Vacuum advance at idle is not good for a zook because the original Aisin gave no vac advance at idle either, the zook was designed that way.
Some SU's have the vac takeoff on the air filter side of the butterfly but most seem to have it on the manifold side of the butterfly, hence my little mod.
If you have vac advance at idle, it means you have already advanced the ignition timing and as you progressively rev the engine you apply even more ignition advance, which is not good for our zook that was designed to have none at tickover.
It would be safer to run with no advance and adjust the static advance a bit so you have an average amount throughout the rev range.
The SU mod is so simple to do it just isn't worth taking the risk or spending more time trying to get round it.
I pulled out the original bit of pipe in the carb, plugged it and drilled another hole just behind the butterfly and re-fitted the original pipe with a dab of Loctite, job done.

Does that make sense?

Nigel.

dunk · Posted: Mon Nov 12, 2007 8:59 am Post subject:

Top job there Nigel Applause

. Great idea to try to beat the carb icing issue. Wink

Zuk-D-Limit · Posted: Tue Nov 13, 2007 11:18 am Post subject:

Nice stuff. When I get to spain im going to rty an SU ive had enough of the webber Evil or Very Mad

Wont have to do a water jacket as its not cold enough in Malaga Cool

suzukishrek · Posted: Tue Nov 13, 2007 1:21 pm Post subject:

Top write up as always Nigel - you are Mr SU. Laughing

Rightly needs to go into the sticky and should just about answer any question on SU's.

It's good to see that "little hole" on the manifold being used for something useful. Laughing

4x4bigstu · Posted: Wed Nov 14, 2007 8:56 pm Post subject:

Nice Job mate,

Smart thinking on the heater, Was it a ****** to seal?

Nigel Head · Posted: Wed Nov 14, 2007 9:21 pm Post subject:

Cheeky Stu - my welding isn't that bad!
I soft soldered the bit of copper tube in with a torch and plumbers solder wire, when you've plumbed in your own central heating (in copper tube, not this modern plastic push fit sh*t) you get a knack for applying just enough heat to do the job properly Wink

It runs sooo much smoother now and I'll give it a good thrashing on Sunday and we'll see how good it is (or isn't).

Nigel.

teamtom · Posted: Wed Nov 14, 2007 10:43 pm Post subject:

it will be fine nigel!

There isn't a better carb to be honest! HIF is the best at what it does! Should be awesome. She'd run upsdie down given half the chance Laughing

Brettyboy · Posted: Wed Nov 14, 2007 10:49 pm Post subject:

Lookin forward to seein the lwb in action on Sunday Nigel,hopefully you won't have to prove it can run upside down or on its side Wink

mlines · Posted: Thu Nov 15, 2007 7:59 am Post subject:

For those of you SJ410 owners feeling left out.... Wink

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150182539795&ru=http://search.ebay.co.uk:80/search/search.dll?from=R40&_trksid=m37&satitle=150182539795&fvi=1

Blatant advertisement for the greater good of owners of 410 screamers

Martin

Tramp · Posted: Thu Nov 15, 2007 5:33 pm Post subject:

quick question, what size fiting did you use for the 'heater pack' inlet? and what size did you use for the vacccum takeoff point? im thinking of moving mine, but rather than drilling the carb, i was thinking of fitting it to the inlet manifold.

the other thing on the adaptor i have bought there seems to be a lip around the inside of the pipe , (where it is welded to the bottom flange, is it worth me grinding the lip back until its flush against the tube?

cheers
luke

Nigel Head · Posted: Thu Nov 15, 2007 7:15 pm Post subject:

Luke, the answer to your questions is already in my posts...

Tramp · Posted: Thu Nov 15, 2007 8:15 pm Post subject:

oh! i thought we were going the other way with the vac take off point! d'oh!

lol i couldnt understand why mine was so close to the butterfly valve! thanks for the pipe sizes i guess i should have looked abit closer, i might do something similar but with out the heater pack, and just run the water through the block manifold,

as for cleaning up, when i was looking at yours it looked like you had done some fairly extensive grinding work around the block manifold inlet, so ill do the same,

next on the shopping list, a dremel!

and another quick question about the air filter, how have you done yours? iv not fitted my su yet but i want to make sure ive got everything ready so that when the time comes it will fitt together nicely,

and finally, that pipe that usually gets crushed on the side of the su, although you wrote that you blanked it off there seems to be a rubber hose going to it, did you decide to use it in the end?

luke

Nigel Head · Posted: Sat Nov 17, 2007 11:28 am Post subject:

I did grind the manifold inlet a fair bit so as to get a reasonably clean airflow.

The carb big inlet tube from the original donor car is capped off in the pics above, but it was just temporarily done with a scrap of tube with a bolt pushed into it!
You could just crush it and hope for a good seal.
The finished article...

Pic18

I moved the original air filter from the O/S to the N/S wing and plumbed it up with an assortment of rubber tube/flexy hosing/68mm rainwater pipe bends !

Pic19

Yes, the bonnet does shut without it fouling anything.

I reckon a snorkel would be good now...

Nigel.

Tramp · Posted: Thu Dec 06, 2007 2:17 am Post subject:

as far as i can tell my vac take off point is on the air filter side of the butterfly valve,
and i was thinking about the spring, you said you upgraded to a yellow one, why? what difference does it make how strong the spring is?

Luke

Andy B · Posted: Thu Dec 06, 2007 2:34 am Post subject:

Hi Nigel,

Just a quick question since im thinking of giving my SU another go again...

What did you use for the accelerator cable? when i had my SU on, the standard one was far too short.. the one youre using looks spot on!

love the idea of the waterway... wish my adapter wasnt made of ali now... Rolling Eyes

Cheers,
Andy

Nigel Head · Posted: Thu Dec 06, 2007 9:44 am Post subject:

Luke,
Your vac take-off looks to be on the air filter side of the butterfly.
I can just see the small hole at approx 11 o'clock near the top of the brass butterfly.

Stronger spring is to prevent the dashpot rising too quickly and giving too much air and a 'flat spot' when you hit the loud pedal.

Andy,
I just made a new cable from something I got from my local auto spares shop, can't remember what they said it was originally for...but it was maybe a foot longer and I cut it to suit.
I just took in my old cable and they rummaged around and found one that was longer and had the correct pedal nipple.

Nigel.

twozooks · Posted: Thu Dec 06, 2007 10:11 am Post subject:

I would say that if there isn't a hole on the manifold side of the butterfly then the vac take off is in the right place Confused

My hif38 has 2 holes in the same place but the vac take off is still on the otherside of the butterfly.

Check the otherside Luke and post a pic Wink

Edit: (this is a hif38 btw, but you get the drift Wink

)

Although taken at an angle the right hand side hole is the vac take off here, the blackish line is where the butterfly sits when closed.

Tramp · Posted: Fri Dec 07, 2007 6:44 am Post subject:

okay well here it is,

and Nigel, i was thinking maybe your using the red spring because your engine is the vit and it has a bigger capacity so it will suck the dash pot and make it rise quicker, will i be okay using the standard one in mine (for a Sammy) or should i get a red spring to?

Luke

twozooks · Posted: Fri Dec 07, 2007 9:54 am Post subject:

Grief

That's a tiny hole compared to the 38, don't think i saw it on the first pic Embarassed

. Read Nigels 11 o clock as 1 o clock Embarassed

Should have gone to specsavers Sad

Modded mine yesterday as it happens Cool

Nigel Head · Posted: Fri Dec 07, 2007 10:06 am Post subject:

Luke,
You have the ideal SU as the vac take off is perfect Wink

I used a std red spring in my sammy and it was just fine.

I'd also solder up that little sprung loaded 'poppet' valve in the butterfly (as in your last pic above).
It may cause the engine to 'surge' a little when holding back on a steep slope etc by opening, shutting, opening, shutting......

Nigel.

Nigel Head · Posted: Fri Jan 04, 2008 9:36 pm Post subject:

I found a couple of YouTube vids on SU's - basic principle hasn't changed on all variants of SU carbs.

http://www.youtube.com/watch?v=7GRAcqDySog&feature=related

http://www.youtube.com/watch?v=60Bj_2cZQnc&NR=1

Nigel