SU Carburettor Conversion

vern jones · Post by **vern jones** » Wed Jun 01, 2016 10:12 pm

Hi there I have just placed my order with SU for their triple carburettor conversion for my S2 2+2 69. Has anyone bought one of these kits from them and what did they reckon.
Many Thanks
Vern

Post by **1954Etype** » Wed Jun 01, 2016 10:43 pm

They are good, but, set them up on the bench first. (Centralise jets, ensure butterflies close, choke linkage is set up etc.

vern jones · Post by **vern jones** » Wed Jun 01, 2016 10:59 pm

And are they worth the expense, I am hoping so.

PeterCrespin · Post by **PeterCrespin** » Wed Jun 01, 2016 11:24 pm

Price/value. The first one is easy - it's a number. The second one, only you can decide. If the car is an auto I'd have done the transmission first. If it's a manual and a US car (and you already did the secondary choke mod but wanted more), then triples are not a bad call. Be sure to get a suitable Series 1-spec distributor to replace your Federal/Emissions jobbie.

Nickleback · Post by **Nickleback** » Thu Jun 02, 2016 6:29 am

Hi Vern,

Yes I did and am very pleased with them, the difference between the original out of tune OEM "Stranglebergs" and the new SU's was / is amazing and well worth it.

The disappointing part was the long wait to get them (about 3 months) and the quality control of the work on the manifold which is a known issue. Mine was supplied new with an apperture actually restricted - So check your manifold carefully when you get it.

Post by **1954Etype** » Thu Jun 02, 2016 7:34 am

As Pete says, its a number. Just don't think they are a bolt on and go extra. The transfer pipe has to be changed (or original modified), the original choke cable has to be swapped for a piano wire type and the distributor changed. The Distributor Doctor can rebuild your original unit and add the vacuum advance and retard. Finally, if you have the original style air filter assembly, the brackets have to be moved on the plenum to fit onto the joiner between carbs and plenum.

abowie · Post by **abowie** » Thu Jun 02, 2016 10:02 am

vern jones wrote:And are they worth the expense, I am hoping so.

Triple SU's vs twin Strombergs?

Win every time.

vern jones · Post by **vern jones** » Thu Jun 02, 2016 9:45 pm

Thank you all for your notes they are very helpful. The wait is the most annoying part I must admit. I feel I need to get these SU's fitted, the engine was rebuilt in the states a few years ago and some fast road cams fitted which do make it a little lumpy on idle but will love the extra flow the SU's will give. Well fingers crossed.
By the transfer pipe do you mean the coolant top hose.
Distributor wise it does appear to be a new unit fitted (no vacuum) so will have to look into that further.
Some people say the difference is amazing some you don't notice ny improvements. Odd

abowie · Post by **abowie** » Thu Jun 02, 2016 10:10 pm

vern jones wrote: Distributor wise it does appear to be a new unit fitted (no vacuum) so will have to look into that further.

It is possible to retrofit a vacuum canister to the standard distributor if you wish. I have done so on my 1.5.

It would be a good idea to get you distributor checked as the curves vary (yours may be a 41207). The correct dizzy for the Stromberg/Smog cars runs a maximum advance of about 40 degrees. This was to allow for the relatively lean mixture from the smog setup.

The 41060 is the dizzy for the triple SU non smog cars; it peaks at about 34 degrees.

With experience and the right equipment it is not hard to correctly calibrate a distributor for a particular curve, and any decent classic car mechanic should be able to do this for you.

Woolfi · Post by **Woolfi** » Fri Jun 03, 2016 7:32 am

" . . .he difference between the original out of tune OEM "Stranglebergs" and the new SU's was / is amazing and well worth it."
1. How would be the difference between two "Stranglebergs", which are well in tune with correct mixture and three SU's ?
2. Has anybody mounted two SU's instead of 2 "Stranglebergs" to the motor and checked the power ?
Regards Wolfgang Gatza

PeterCrespin · Post by **PeterCrespin** » Fri Jun 03, 2016 2:58 pm

Woolfi wrote:Has anybody mounted two SU's instead of 2 "Stranglebergs" to the motor and checked the power ?

Yes, Jaguar did.

The whole world got two HS8 SUs on their 4.2 XJ6, except America which got Strangled. The power outputs are probably in the brochures of the time.

vern jones · Post by **vern jones** » Fri Jun 03, 2016 5:20 pm

thank you some real good comments.
Think I need to get to some meets or find someone local to compare with.

Nickleback · Post by **Nickleback** » Fri Jun 03, 2016 9:09 pm

Vern,

Where are you based, can you update your general location so we know who is close to you ?

Post by **mgcjag** » Fri Jun 03, 2016 10:28 pm

Hi Vern....Im in Ludlow.....PM me... I have a UK spec 69 S2 2+2 if you need any help

Herzeg · Post by **Herzeg** » Sat Jun 04, 2016 9:14 pm

Pardon my ignorance, but what's the secondary choke mod on the strombergs?

I have a good running motor but think I have the wrong dizzy so that's no 1 priority. Second is to see if I can refurb and squeeze more power out of the carbs. I think they are in good nick as it starts easily but I think it's not tops on power.

John

PeterCrespin · Post by **PeterCrespin** » Sun Jun 05, 2016 1:33 am

Herzeg wrote:Pardon my ignorance, but what's the secondary choke mod on the strombergs....John

It was described again here recently and several reported back on the immediate improvement, but this is the original (?) thread I found:

viewtopic.php?p=23408

AussieEtype · Post by **AussieEtype** » Mon Jun 06, 2016 12:30 am

Hi Pete - just had a read through the references you put up and it talks about Federal cars and in the context of 6 cylinder cars.

Do you know if the fix will also apply the carbs on UK V12s?

thanks

garry

PeterCrespin · Post by **PeterCrespin** » Mon Jun 06, 2016 3:19 am

My mod only relates to the secondary throttle butterflies on 6 cylinder North American cars. Whilst all the carbed V12s do have Stranglebergs, the North American ones have lower compression etc. but no such secondaries, so the mod doesn't apply.

The carb plenums on S3 E-types ARE bored for 2" carbs as I recall, so at WOT it might pay to fit 2" SUs, but it's unlikely to be worth your while, even then.

AussieEtype · Post by **AussieEtype** » Mon Jun 06, 2016 4:22 am

Thanks Peter - just thought I would ask.

Cheers.

Garry

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