su carbs

[andrew ford]

is there anyone near abingdon oxfordshire who can help me set up the carbrettors on it?

[Mike Stevens]

Hi Andrew,

I'm near Didcot if that helps. I've got SUs on my 2000 as I prefer them to Strombergs.

I would have thought that a '73 car would have had Strombergs.....

What needs setting up?

Cheers,
Mike.

[andrew ford]

yes it was fitted with strongburgs but i changed them to atually get it running as the old ones
took half an hour to get it to start. the sus are running very rich and has sooted up the plugs of whitch i ve replacements that i am going to fit. but i need somone who has the knolage to get them running less rich.

[Mike Stevens]

Hi Anthony,

First of all where did the SUs come from? If from a late 2500 the needles will be wrong, probably making it run rich. With the wrong needles you'll never get it to run right over the whole rev range. I spent some time looking at the needle charts when I put SUs on my early Mk2 2000, but these day it's all on the internet. A poster on here has got a website with the needle charts etc on. Can't remember his user name at the moment - must be old age!

If you get some late 2000 needles they'll be a good starting point. I assume they are SU HS6s?

Cheers,
Mike.

[andrew ford]

i think they are hs4 carbs but the nedles i ordered from burlens did not fit correctly so i had to put original ones back in. the choke does not seem to lock like you used to be able to on the old strongburgs? could the problem be an incorrectly set up choke?

[Mike Stevens]

HS4 are 1.5", HS6 are 1.75". Did you get a different inlet manifold too? The HS6s go on a longer inlet manifold that has a thin air 'box' and a flexible trunk to a single air filter down by the radiator. HS4's are probably on a short manifold with a separate air filter for each carb, but a different manifold than used by the Strombergs. If you measure the diameter of the carb where the air filter goes, that should be 1.5" for HS4s or 1.75 for HS6s.

If the needles you got from Burlen didn't fit, it would suggest that they are not for the carbs you have.

Here's a picture of the HS6s in my 2000. Sorry about all the dust!

You can see the long inlet manifold.

You can lean out the mixture by screwing in the adjustments, but although you could probably get it OK at idle, if the needles are wrong the mixture will be wrong at different engine speeds and loads.

If you take out a needle you can see it's type. The numbers/letters are stamped around the boss where it fixes into the air slide thingy. I have lists for the needles used in the big saloons and I can look them up, but will be away for a week so won't be able to until next weekend.

Where are you in Abingdon?

Cheers,
Mike.

[Alec]

Hello Andrew,

yes the choke(s) can stick, on the HS4 the choke is a link to the jet tube which is pulled down by the action of the choke cable (one on each carburettor, choke that is, not cable).

The needle for a 2000 is an ABL, fit the needle with it's shoulder flush to the bottom of the piston. Before refitting it to the carburettor, wind the jet tube up using the adjusting nut so it's flush with the carburettor bridge, then wind down again by two full turns of the adjusting nut, this is the datum position for the mixture and should be very close to optimum.

Alec

[andrew ford]

the carbs i have the short manifold as there is the big airbox, the needles i have are half the size of the orignal ones and when fitted dont seem to fit or let the engine run properly but when the original needles where put back in the car run the best it ever has it but was very smokey. and i am on audlett drive, sorry for all the writeing.

[mauvstag38]

Hi All,
I have a 71 mk2 is there any advantage to having SU,s over Stromberg,s, mine is just a standard 2000
by the way I live in Didcot.
Regards George.

[Mike Stevens]

Hi Andrew,

I'm now back in the UK!

It would be interesting and even useful to know the needles that were originally in there and the new ones from Burlen. Alec has already stated an ABL needle for a 2000 (is that for HS6 or HS4 Alec?).

You say the car smokes, but what colour is the smoke? When too rich, I would expect it to run badly before it smokes a lot. Black smoke is probably too rich mixture, blue smoke burning oil. There are other colours associated with other issues too!

I guess there is nothing wrong with Strombergs, I've run many 1000's of miles on them. I just prefer SUs and, as they are just a bolt-on change, it's a relatively simple mod.

Cheers,
Mike.