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31 Jul 2007, 14:50 (Ref:1977314) | #1 | ||
Racer
Join Date: Jul 2006
Posts: 244
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SU Carb Needles/Jets
Hello all. I considered posting this in racing technology but it didn't seem terribly technological and I thought I might find more expertise here! I've finished the engine build on my Spitfire and driven it about 100 miles on the road. I upsized to 1.5" SU's from 1.25" that were on the car. It has a 280 degree cam, full 4-2-1 manifold & exhaust, fan replaced with electric, head skimmed to give 10:1 compression and 3 angle valve seats. I'm concerned that it is running too rich and needs different jets and needles. Not being a rich man I can't afford to take it straight to a rolling road and pay them for an hour of their time, although I will have to pay someone to set the ignition timing correctly. Does anyone have any practical tips for setting up the carbs and getting the right needles/jets?
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Alias - Stuart Dickinson. I am serious, and stop calling me Shirley. |
31 Jul 2007, 16:27 (Ref:1977415) | #2 | ||
Veteran
Join Date: Sep 2006
Posts: 12,853
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It would help to know what needle/jet sizes you have now. To spend ,say 60 quid now could possibly save a rebuild in a few races time.
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Living the dream,Chief instruktor and racing on the worlds best circuits-The Nordschleife and Spa.Getting to drive the worlds best cars-someone has to do it, so glad its me. |
31 Jul 2007, 21:10 (Ref:1977639) | #3 | ||
Racer
Join Date: Jul 2006
Posts: 244
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Is there anywhere in the London/SE area that I could go? I think its worth spending a little bit but I don't want to drop the car off and come back later to find that I'm getting billed for 4 hours time. I just want to get the right needles & jets put in and have it set up properly.
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Alias - Stuart Dickinson. I am serious, and stop calling me Shirley. |
1 Aug 2007, 10:46 (Ref:1978077) | #4 | |||
Veteran
Join Date: Jul 2002
Posts: 3,499
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SU Needle Selector
Quote:
Don't forget to check the springs as well. A useful site for selecting and comparing needles is http://www.mintylamb.co.uk/suneedle/ The needle matching program is called "WinSu" - do a google search. |
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The good old days sure seem like a long time ago!! |
1 Aug 2007, 12:09 (Ref:1978162) | #5 | |
Rookie
Join Date: Aug 2007
Posts: 83
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Southern Carburettors in Wimbledon are very good and have a rolling road. Unit 6, Nelson Trading Estate, Morden Road, Wimbledon SW19 3BL - 020 8540 2723. Not sure of costs but I have always found them very sensible and competitive.
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1 Aug 2007, 13:19 (Ref:1978234) | #6 | ||
Racer
Join Date: Dec 2006
Posts: 394
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Hey Brendan - have you finished my father's old Elite yet???
I'll be racing the 18FJ at Combe this weekend, and John will be racing it at the Gold Cup! Will you be there? |
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Sarah Hutchison Track Days, Motor Race Events Management, ARDS Racing Instructor, Land Rover Off-Road Instructor, Wine Taster, Gardener, Domestic Engineer! |
1 Aug 2007, 15:33 (Ref:1978320) | #7 | ||
Veteran
Join Date: Apr 2004
Posts: 3,820
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Another well-satisfied customer of Southern Carbs
Give them a call to check the hourly rate, Dave is the r/r operator so ask for him, mention me if you like, he sets up my Midget. If you ask nicely and sign the visitor's waiver book, they will let you stay in the workshop and watch. Don't forget to take a notebook and write down all the settings, needles, etc, so you know the spec when it's finished. |
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a salary slave no more... |
1 Aug 2007, 15:35 (Ref:1978322) | #8 | |||
Racer
Join Date: Dec 2006
Posts: 394
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Sarah Hutchison Track Days, Motor Race Events Management, ARDS Racing Instructor, Land Rover Off-Road Instructor, Wine Taster, Gardener, Domestic Engineer! |
1 Aug 2007, 16:15 (Ref:1978352) | #9 | |
Rookie
Join Date: Aug 2007
Posts: 83
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TorqueWench, Elite is in the paint shop, most of the major components are on my garage shelves, rebuilt and waiting to be fitted and the engine was collected by the engine builder at S'stone, so hopefully making real progress at last. Been sharing Steve Hill's car this year.
Will be at Castle Combe spectating whilst my wife and children visit Granny! See you there! |
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1 Aug 2007, 16:38 (Ref:1978365) | #10 | ||
Veteran
Join Date: Apr 2004
Posts: 3,820
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where's the Mod when you need one ? |
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a salary slave no more... |
1 Aug 2007, 19:40 (Ref:1978509) | #11 | ||
Race Official
Veteran
Join Date: Mar 2003
Posts: 13,226
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I'm here, I'm here ...... and trying to show tolerance!
On the other hand .... |
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1 Aug 2007, 20:04 (Ref:1978534) | #12 | |||
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Join Date: May 2004
Posts: 1,479
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did anyone find my 3/4-7/8 GEDORE ringspanner at SPA? |
1 Aug 2007, 20:17 (Ref:1978546) | #13 | ||
Race Official
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Join Date: May 2003
Posts: 11,143
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You could get the Burlen Fuels book on SUs or the Veloce book on tuning SUs, both very helpfull and not too expensive. Dont forget the jets will be the same, you only change the needles and springs.
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2 Aug 2007, 09:05 (Ref:1978879) | #14 | |||
Racer
Join Date: Dec 2006
Posts: 394
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Sarah Hutchison Track Days, Motor Race Events Management, ARDS Racing Instructor, Land Rover Off-Road Instructor, Wine Taster, Gardener, Domestic Engineer! |
2 Aug 2007, 15:52 (Ref:1979156) | #15 | ||
Racer
Join Date: Jul 2006
Posts: 244
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Thanks for the advice guys.
I've contacted Southern Carbs and they said £150-225 for a rolling road session + £20ish for needles if they are needed. Does that sound reasonable? Sarah, I'm definitely hoping to race it. Considering a few places but the CSCC is definitely one of them - I might have a few friends along to have a go with me. In fact, I think you know my friend Jamie Harfoot? |
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Alias - Stuart Dickinson. I am serious, and stop calling me Shirley. |
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