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6 cyl Bristol cars Type 400 to 406 - restoration, repair, maintenance etc

Solex emulsion tube availibility

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Old 22-11-21, 08:47 AM
Join Date: Sep 2021
Posts: 18
Default Solex emulsion tube availibility

My previous Jetting post was prompted by my investigation into why I have a occasional spit back from the centre carb. when I dragged out all the easily accessable jets etc I found some differences. The biggest difference seems to be the emusion tube on the centre carb is vastly diffent from the F & R (centre marked 13 and F & R marked L24) the L24 have a row of holes (4?) down each side of the tube and the 13 only has 1 hole on one side and a few on the other. This makes me think that this may be some of the reason for the spitting back. All the other jets are pretty close (centre Main Jet -175, F & R 180. the rear has a smaller pilot jet than the F & centre - R - 44, F 7 C 55).
I ran the car in complete darkness whilst observing the distributor/HT leads etc and there was no sign of 'tracking' or wayward earthing at all.
SO, is there a supplier of emusion tubes out there?? I could find jets, repair kits etc, but not emulsion tubes.
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Old 22-11-21, 09:01 AM
Join Date: Jul 2008
Location: Meriden near Coventry
Posts: 72

We have discussed this here before, but the reason for different jetting was that the central two cylinders fire on alternate complete revolutions, whereas the outer two pairs are not evenly spread so one cylinder starts inducting before the other one has finished. There is a danger of a leaner condition due to the more intermittent nature of the air-flow, so slightly richer jet settings are used, e.g. 5 points up on the main and/or 5 or 10 points down on the air corrector. I have no idea why the emulsion tubes would be different. I suspect that any differences in emulsion tube are due to later experimentation, rather than a factory setting.
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Old 22-11-21, 09:14 AM
Join Date: Sep 2021
Posts: 18

Thor, many thanks for the prompt reply. So why the difference between early and late 405? surely the cranks are the same (I'm assuming here - dangerous!!) Also this seems to be the only example of differences in the cente v F & R on Bristol/ 328 engines that I know of.
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Old 22-11-21, 11:09 AM
Join Date: Oct 2009
Location: Melbourne, Australia
Posts: 26


See my reply to your other thread re the differences between early and late 405

Your current set up seems very idiosyncratic
Without putting the car on a rolling road dyno (or the engine on an engine dyno) I suspect it will be very difficult to make sense of that set up - unless the chap who set it up can tell you what specifically he did and why

different emulsion tubes is very very strange, unlikely to be necessary and will make the car very difficult to tune
the L24 was only used on some BS1 engines, the 13 emulsion tubes are also sports engine emulsion tubes (FNS and different BS1s)
The main jets are HUGE for a Bristol engine, and if you are doing different F/R and C then they are the wrong way round - the richer jet should be on the center pair not each end
Having said all that, you need to know and understand the air correction jet sizes (as that affects the effect of main jets and to some extent the emulsion tube) - what are they?

The mismatched pilot jets is also highly unusual (and i presume you mean 45 rather than 44 - those jets are sized by 5s) and again you need to look at the pilot air correction jets to understand what they are doing

The carb settings interact with the camshaft profile - what cam do you have in the car

Without further information it does look like someone was trying to do a "sports engine" set up (bits of BS1 with huge oversized main jets) but ran out of bits. The other (less likely) possibility is that this is actually an exquisitely well set up engine and the bits are all working together well - in which case the only real option is to take the car to the chap who set it up and have him sort it out

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Old 24-11-21, 06:50 AM
Join Date: Sep 2021
Posts: 18

'Carburettor Hospital - Specialists in carburettors and spares'
contact details via the web. They had all I needed to get my carbs similarly jetted. How it all goes will follow!
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