SU Carburettor

[Tiger]

Hello People
Has anyone used a SU with 30 degree angle body to float chamber.
The carb I have is AU 40
Looks like 1 1/8” bore

[John Cornforth]

Hi

This might be an H1 (1 1/8 inch) as originally fitted to a Morrris Minor.

SU list the AUC 704 or AUC 738 for the 1953-1956 Series II with the OHV 803cc 'A' series engine (30 BHP)

The same engine was used in the Austin A30, but this had a Zenith because SU were owned by Morris who were still a rival until the BMC merger of 1952.

You're unlikely to get full piston lift with the maximum airflow of an A7 engine (unless it's highly tuned), but this doesn't seem to matter greatly. I use an earlier type sidedraught H1 (Morris 8 Series E) with a GG needle as per the later application and it works well.

[Tiger]

Thanks John
Do you think it’s possible to adjust the float chamber to get it vertical?
With respect to lift possibly leave out the piston spring

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Sorry the number on the float chamber is AUD 40

[Steve Jones]

You will need a different float bowl . Fully interchangeable with the angled bowl. Look on Burlen's web site for the options.

Steve

[Chris KC]

I don't know what angle the carb on my Ulster is without measuring it, but it's a 1 1/4" (AUD 13 - 1098cc Morris Minor).
I have a cast aluminium inlet manifold which does the job - but which needs to be paired with an Ulster- style exhaust manifold. 
On my Nippy for many years I ran with a Reliant manifold (which takes a downdraft carb, but fits the A7 directly) and a short adaptor tube to give the requisite angle.

[John Cornforth]

Hi again

SU list the AUD 40 as an HS2 (1 1/4 inch) type as fitted to the 1961-1970 Austin A60 1622 cc and the similarly engined Morris Oxford VI. A GX needle was standard. An HS2 is a bit large for an A7 but people have used them in the past. Taking out the (Red) spring will give more piston lift for a given airflow, but you may still find that you are only using the first part of the needle so selection might be a bit more critical. Worth trying though.

[Belinni]

With the 1-1/4” a lot of people have found that changing to a blue spring and no.6 needle works for them. Others have good results with different needles.

[Charles Levien]

With the 1-1/4” a lot of people have found that changing to a blue spring and no.6 needle works for them. Others have good results with different needles.

My set up exactly — works well

[Tiger]

Many thanks for the replies Gents.
Probably not the best choice for my Ruby.
Going to have another look at 26 VA to see what that yields
Regards
Tim