su's on v8

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ew_topcat

Original Poster:

1,938 posts

256 months

Saturday 19th July 2003
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Can someone give me a good way to setup the carbs on my standard 3.5 v8. One of them seems to be running far richer then the other. Ive blanked off the emmisions nonsence as it has k+n's on it. thanks topcat.

GreenV8S

30,479 posts

291 months

Saturday 19th July 2003
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ew_topcat said:
Can someone give me a good way to setup the carbs on my standard 3.5 v8. One of them seems to be running far richer then the other. Ive blanked off the emmisions nonsence as it has k+n's on it. thanks topcat.


Assume you have identical springs and needles, and both dampers are filled with the same oil? In that case I would have thought the only thing to get wrong was the jet height adjustment. Should be the same on both carbs, obviously.

ew_topcat

Original Poster:

1,938 posts

256 months

Saturday 19th July 2003
quotequote all
thanks greenv8, I think they are the same neddles etc. Just checked oil and was very low/poor in both, which is the mixture screw on carbs, is it advisable to wind them both in and then out equally until it ticks over correctly?

GreenV8S

30,479 posts

291 months

Sunday 20th July 2003
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ew_topcat said:
thanks greenv8, I think they are the same neddles etc. Just checked oil and was very low/poor in both, which is the mixture screw on carbs, is it advisable to wind them both in and then out equally until it ticks over correctly?


The jet height adjuster is a recessed screw inside a boss sticking out the side of the float chamber near the bottom. Screw in to lower the jet. This is usually covered with a plastic blanking plug and once it is set up for a particular engine it is normally sealed for life, not user serviceable, don't fiddle with this bit. It is not at all easy to set this, and not really a good area for experimentation unless you're comfortable setting them up from scratch. If somebody has fiddled with it for you, you could be in trouble. Best hope the blenking plugs are still in place and the dampers are your only problem. Also, nearly forgot to mention, the two throttles should be balanced i.e. drawing similar flows. This makes more difference at idle than at power. Final point, idling is very sensitive to ignition timing.

Hope this helps.

No 1

225 posts

257 months

Wednesday 6th August 2003
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Topcat

Not really much use to you as you're in Devon, but I sent my V8 with twin Stomburgs in to a local carb specialist just outside B'ham and couldn't believe the difference. It was in for about an hour and half and cost about £65.00. Money well spent since unless you know what you're doing, it can all go very wrong and it was like a differnt engine afterwards.

Might be worth checking out any specialists in your area - particularly if they are prepared to talk you through what they do so that you can do it yourself next time.

SLiller

59 posts

265 months

Thursday 7th August 2003
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A tip I got years ago thats works well with SU's.
If you messing about with them or they run badly etc.
Undo the three screws holding the piston damper etc and lift off, now you see the jet on a raised bridge section across the carb. Wind the jet till its flat with the bridge then wind it back down two full turns of the adjusting screw and it will run!. It works well when you are trying things out and get lost.
Just remember if the jet is two turns down you have a good starting point with a running engine!.
Hope this helps.

>> Edited by SLiller on Thursday 7th August 15:30

ew_topcat

Original Poster:

1,938 posts

256 months

Thursday 21st August 2003
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thanks for the replies guys, will try and find a specialist soon as I am losing faith and thinking of selling the beast. Hope to have a more upbeat post soon.

eliotmansfield

11,727 posts

261 months

Friday 22nd August 2003
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>> Wind the jet till its flat with the bridge then wind it back down two full turns of the adjusting screw and it will run

2ba 355

166 posts

262 months

Friday 19th September 2003
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Try this website or ring them, apparently they are very helpful. www.gowerlee.dircon.co.uk/Tips.htmAlso try this there is a lot of info on V8's here and a good FAQ page.http://pub105.ezboard.com/boffroaderrantpage

>> Edited by 2ba 355 on Friday 19th September 14:39