Goldilocks needles - CV, WO or ?

[John Summers]

Hi all, my first Forum post so be kind to me!

A few years ago I was weighing up CV vs WO needles for my 4 1/2 - at that time general opinion was WO needles better at road speed, a bit rich and smokey on tickover but something you lived with.

Just wondering if anyone has looked at this recently - are there any needles with better profiles being used on WO engines? Is there much variance in requirement between 3l, 4 1/2l, 6 1/2l and 8l? Another angle could be to see if we could find someone with modern technology to see if they can produce something with an updated profile?

John

[John Murch]

Welcome to the forum.
I expect that you have already had a look round the forum, there are a number of discussions on needles, but these are probably aimed at wear. Eg. https://www.bdcl.org/forum/viewtopic.php?t=3887&highlight=needles
I tried looking into the subject a few years ago, speaking to a couple of the successful competing members, but they all seemed to use standard needles.
Most problems seem to be improved by renewing the jets, needles and cork seals, it’s surprising how much they wear.
I think the technical facts book has a table on the needles for the different models, I’d have a look but my copy is not to hand.

[John Summers]

John, many thanks for the comments. I'll check the Technical Facts as a starter . I guess what's needed now is some decent road miles road testing!
Best regards
John

[John Murch]

I don’t know if it makes much difference on needles, but which carbs does your car have? Also a session on a rolling road could be very informative regarding how rich you are running at what rpm.
John

[John Summers]

John, I managed to pick up a triple carb manifold a few years ago, and get a third HV5 to add to my existing two, will try to upload photo for amusement. General feeling was it wouldn’t make much difference, but in fact think it helps, presumably in general breathing. Surprisingly, I think the setup has even improved fuel consumption by between 5-10%. It’s just a bit smokey at Rickover, ideally would like to get better. John

[John Murch]

Looking forward to seeing a photo. I imagine there are not many people with a similar set up to advise on needles.
I seem to remember that there was a successful competition car with a 3 carb set up, but I can’t remember which. I’m sure you know!

[John Summers]

John, Have tried to upload photo repeatedly though ipad and laptop - it uploads the file, then on send resets to being blank! I understand my carbs more than this system. If you are in the book will email - maybe will call BDC on monday and see if I can resolve. The manifold looks a professional casting; it may not be original WO but certainly has some age to it. Cheers John

[John Murch]

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