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SU carburettor identification help


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#1 Catalina Park

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Posted 19 September 2011 - 09:40

A friend on another forum wants to know what sort of car these SU carbies are off.

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I am thinking British for obvious reasons but apart from that I have no idea. Can any of our experts help?

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#2 RTH

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Posted 19 September 2011 - 12:11

H1 or H2s from the 1930s ?

#3 Allan Lupton

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Posted 19 September 2011 - 14:02

Probably post-war with the distributor vacuum pipe. Tubular dowelled inlet ports, but only two of them, were what some BMC A and B series conversions used, and these look B series size.
If so, it's a conversion as Riley 1.5 used HD carbs (semi-downdraught); can't remember what the MGA used but the mixture control and air box are not MGA.
Actually, now I look a bit closer, the carbs are a bit unusual as the throttle spindle housing is integral with the mounting flange (normally well separate) and the flange shape is also unusual.

Edited by Allan Lupton, 19 September 2011 - 14:03.


#4 RTH

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Posted 19 September 2011 - 15:38

Not totally certain from the pictures are these in fact horizontally mounted i.e. the dashpots and float chambers in a vertical plane.
Is that a vacumn take off , some SUs had copper petrol drain pipes for excess petrol that lead away to under the engine just above the ground ?

These people certainly used to be very helpful

http://www.sucarb.co...lenHistory.aspx


http://www.sciperfor...ge_1822386.html

Edited by RTH, 19 September 2011 - 15:39.


#5 Allan Lupton

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Posted 19 September 2011 - 18:09

Not totally certain from the pictures are these in fact horizontally mounted i.e. the dashpots and float chambers in a vertical plane.
Is that a vacumn take off , some SUs had copper petrol drain pipes for excess petrol that lead away to under the engine just above the ground ?

The float chamber tops and the choke tubes look to me to be parallel which is why I agree that they are H as you wrote first, not HD.
The pipe starts as a tapping near where the throttle butterfly rests when shut which is the vacuum advance place. Overflows start between the float chamber top cover and the nut that secures it.


#6 cs3tcr

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Posted 19 September 2011 - 19:23

They're definately H type carbs, HD's had diagphragm jets, so didnt have the choke levers as pictured. They look like early post war carbs (pot metal bodies rather than aluminum), so i'm guessing they're off someting from around 1946-1951 or a conversion kit. The intake manifold looks like it may fit a side valve ford engine, but the air cleaner "box" looks like a mass produced item.

Edited by cs3tcr, 19 September 2011 - 21:47.


#7 Allan Lupton

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Posted 19 September 2011 - 23:08

Aaargh!
HS was what I intended to say they were not (semi-downdraught) rather than HD! Either way H type.
The short body, with throttle close to the mounting flange, was used for Triumph Heralds

#8 Wilyman

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Posted 20 September 2011 - 06:30

Aaargh!
HS was what I intended to say they were not (semi-downdraught) rather than HD! Either way H type.
The short body, with throttle close to the mounting flange, was used for Triumph Heralds




With the two bolt flange mounting they would not be bigger than 1.5", if that ? Certainly look Morris/Austin 90 Atlantic. Another thought could they have come off one of the "log" manifold bigger Austin/Morris Sixes?

Specialist literature on SU's insists that the float bowls be mounted to the front to avoid starvation under acceleration.
A theory that seems to be ignored by some manufacturers ie Triumph TR. Others ?

The contradiction to all this is the SU mounted Mini Coopers.

#9 Allan Lupton

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Posted 20 September 2011 - 08:32

Specialist literature on SU's insists that the float bowls be mounted to the front to avoid starvation under acceleration.
A theory that seems to be ignored by some manufacturers ie Triumph TR. Others ?

The contradiction to all this is the SU mounted Mini Coopers.

Yes, that's normal but with twin carbs on a small engine there is often insufficient space for the float chamber of the rear carb to be in the forward position.
Transverse engines, such as the Mini Cooper's, of course have the carbs parallel to the line of motion so the only "to the front" that can be achieved is built in by the offset between the float chamber mounting and the jet, plus the limited amount of angular movment in the mounting. Nearly as much as the conventional offset, but not quite.

Edited by Allan Lupton, 20 September 2011 - 08:33.


#10 ozdude

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Posted 21 September 2011 - 05:02

Triumph Herald 948cc for sure. The 'log' style manifold , and air cleaner box is the giveaway. Lots of pics on google to confirm.
Cheers, Ozdude

#11 kevinbartlett

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Posted 21 September 2011 - 06:40

Triumph Herald 948cc for sure. The 'log' style manifold , and air cleaner box is the giveaway. Lots of pics on google to confirm.
Cheers, Ozdude


Agree they are from Herald. The size of throttle is 1 1/8" I had a heap to do with SU's when they were the carb of choice for most Pommie cars. Flange shape is dead giveaway.

Edited by kevinbartlett, 21 September 2011 - 06:41.


#12 mikeC

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Posted 21 September 2011 - 06:56

I've only just seen this thread, but I agree, definitely Triumph Herald 948cc, standard fitting on the coupe and convertible 1959-61 (and also the twin-carb saloon!) :up:

#13 Catalina Park

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Posted 21 September 2011 - 10:21

Thanks everyone, I will let the owner of the carbs know what he has.

#14 Ray Bell

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Posted 21 September 2011 - 11:38

Better let him know the coupe had an advertised top speed of 98mph with these fitted...

Did they come from the same sort of place as I saw that Tempo Matador?

#15 GMACKIE

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Posted 21 September 2011 - 22:38

Ray, Graeme Snape told me a couple of weeks ago, that the Zephyr Special had a gear-box issue. I'm sure the trans-axle is from a Tempo Matador, so Graeme may be interested in knowing the whereabouts of that Matador.

#16 Ray Bell

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Posted 22 September 2011 - 03:21

Graeme has several Matador gearboxes and I told him already about this one...

Even so, the Zephyr's box is full of very special gears.

#17 Allan Lupton

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Posted 22 September 2011 - 07:55

Graeme has several Matador gearboxes and I told him already about this one...

Even so, the Zephyr's box is full of very special gears.

Is a Tempo Matador a locally built Ransomes Matador like this?
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#18 mikeC

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Posted 22 September 2011 - 18:43

Better let him know the coupe had an advertised top speed of 98mph with these fitted...


Good Grief! What did they do to the Aussie version? Here in the UK the 1600 Vitesse was claimed to do do 89mph...
From memory, the twin carb 948cc Herald would just about reach 80mph, up from 72mph for the single carb version.
Or do you have smaller miles than we do... :wave:

#19 Ray Bell

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Posted 22 September 2011 - 22:37

That year we were using US miles...

Maybe they found a nice downhill run? Or a tail wind?

As for the Matador, that was a German light truck with front wheel drive powered by a VW flat four. It dated from the early fifties, Allan, I'm sure you'll find it if you Google it. And I suggest you never make light of the Snapes' Eclipse Zephyr!