Carburettors
With regard to SU needles they are all identified by a combination of letters and numbers stamped onto the base.You sometimes need a magnifying glass to see these as they can be quite faint.
There were a huge range of needles manufactured by SU of differing lengths and for the three different sized jets.
If you have the code for your present needles I recommend going to the "MintyLamb Compare - o - rama" web site ( I kid you not!) where you can compare them with others to get the profile that you are looking for.
http://www.mintylamb.co.uk/suneedle/
Most needles are still manufactured by Burlen services who took on all the SU tools and designs etc.
https://burlen.co.uk/
Do make sure that the float levels are correct before making any needle changes and apparently altitude where you live can make a difference to mixture once you get above a few 1000 ft or so.
C Plain-Jones
There were a huge range of needles manufactured by SU of differing lengths and for the three different sized jets.
If you have the code for your present needles I recommend going to the "MintyLamb Compare - o - rama" web site ( I kid you not!) where you can compare them with others to get the profile that you are looking for.
http://www.mintylamb.co.uk/suneedle/
Most needles are still manufactured by Burlen services who took on all the SU tools and designs etc.
https://burlen.co.uk/
Do make sure that the float levels are correct before making any needle changes and apparently altitude where you live can make a difference to mixture once you get above a few 1000 ft or so.
C Plain-Jones
Carburettors.
Standard equipment for a VA's is 2 Skinner Union (SU) type H3. Easily recognised by the casting number 3251 in the main body. Most parts apart from the main body are ready available from most carburettor parts suppliers. Typical modern VA carburettor parts numbers as supplied by Burlen:
Part name Part number
Standard needle AUD 1105 CO
Weak needle AUD 1105 CP
Rich needle AUD 1105 BK
Jet AUC 8182
Float needle valve WZX 1101
Float WZX 1303
Throttle spindle WZX 988
Throttle disc AUC 2300
Gasket pack AUA 25
Fuel pump kit EPK 700
Fuel pump new AUA 25
Biggest problem with VA carburettors is the weakness of the main body made of some kind of Mazac. At the bottom of the main body, in the area where the float chamber is attached develops a crack which can not easily be repaired.
Point of attention for regular maintenance is the hollow bolt with which the float chamber is attached to the main body. This bolt tends to work loose and creates a fuel leak. On the other hand will overtightening of this bolt lead to an early fracture of the main body. Good condition sealing rings and a little LockTite on the thread will help. Another point for improvement is the matching of the carburettor outlets to the carburettor manifold. In most cases the inlet ports of the manifold are much smaller than the carburettors. As there is sufficient material in the manifold they can easily be opened up to improve the gasflow and efficiency.
Running Rich.
Sometimes when you have overhauled your carburettors, new needles, jets, spindles etc it can still happen that one of the carburettors does not respond well to tuning.
In that case it is worth checking the float levels again, but this time in a different way. Switch off the engine after it has been running for some time. Take off the covers of both float chambers and take out the floats. Now measure the exact distance in between the top of the fuel level and the rim of the float chamber. Quite likely there is a difference in between the two levels. This can be caused by two different matters.
One is that your floats may be different in weight. Just put them together in a bowl of water and compare. If the weights of the floats are equal, then they both have the same portion above the water level. If one is floating lower then you have found the culprit.
If both floats are equal then it may be that although you thought that you have adjusted the float levers according the book; one is slightly different adjusted. So if both floats are equal but the fuel levels different adjust the higher level one to closing the float needle earlier.
In the above picture are two genuine unmolested floats at the front and two "overhauled" ones at the back. The back ones (supplied by an expensive MG parts company) are heavier and unstable. Although the back ones should be a straight fit gave much trouble and a not understood far too rich mixture.
BdV
VA SU Carb choke support bracket. Some cars have the choke support bracket which is attached between the carb and the inlet manifold. A few of us believe its purpose is to take the strain off the side lug on the rear SU carb body which is known to snap, and that is probably why this was introduced.
My VA did not have that but Ric copied one for me and I am getting one made and as that involves getting it water cut out and on a computer, the machinist can make more as necessary.
If anyone would like one let me know, it is not complex for I expect NZ$80-NZ$100 as a guesstimate. I attach a photo and also Ric's plan of what will be done. A 3/8" bracket will be supplied, shaped and also the same 3/8" compensating distance piece for the other carb. Will also have a cable clamp.
Side offset is 8cm.
Elmar Galitis
My VA did not have that but Ric copied one for me and I am getting one made and as that involves getting it water cut out and on a computer, the machinist can make more as necessary.
If anyone would like one let me know, it is not complex for I expect NZ$80-NZ$100 as a guesstimate. I attach a photo and also Ric's plan of what will be done. A 3/8" bracket will be supplied, shaped and also the same 3/8" compensating distance piece for the other carb. Will also have a cable clamp.
Side offset is 8cm.
Elmar Galitis