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#1 Stromberg Carburetor rebuild V12 S3

Posted: Thu Feb 16, 2017 10:16 am
by Nomisblue01
Morning All

Well spring is on its way, and car is getting close to MOT.

However carbs are misbehaving with one spitting fuel out. So going for a fettle and rebuild.

Which is the best book to purchase to assist in the job for a novice. have seen a few

Suggestions please.


#2 Re: Stromberg Carburetor rebuild V12 S3

Posted: Thu Feb 16, 2017 10:38 am
by vee12eman
Hi Simon,

There is a Haynes manual for Strombergs, I think it's no longer in print but can be found on eBay etc. The carb described in the section on CDSE & Cd-2SE is the E
V12 E-type unit. It doesn't cover everything as most manuals don't cover pressing out the jets. This is quite important to get right, measure the depth of the jet so you can get it back to the correct depth with the new jets.

ISBN is ISBN 1 85010 060 8 or ISBN 1 85010 019 5 (US).

Float height is important too as is making sure that they don't leak afterwards. The worst leak point is the large O ring at the bottom of the float chambers. Make sure you replace these and clean up the seal mating surface too. I actually used a sealant very carefully too but this must be fuel proof and don't get it inside the carbs. The choke assemblies also can leak, make sure you tighten these well.

Biggest issue is actually reassembling the carbs and associated air pipes. Make sure they are air tight as vacuum leaks cause havoc.



#3 Re: Stromberg Carburetor rebuild V12 S3

Posted: Thu Feb 16, 2017 10:59 am
by vee12eman
Hi Simon,

Just remembered this site: ... content.36

Interesting reading and the rest of the site is great too.

I also remembered that you can strip the bimetallic bypass valves and reset them to open at (from memory) 45 degrees Centigrade by adjusting the nuts and using warm water at the correct temperature Search the net to confirm the temperature.



#4 Re: Stromberg Carburetor rebuild V12 S3

Posted: Thu Feb 16, 2017 11:08 am
by Nomisblue01
Thx for info Simon.

Have also just been quoted about £600 to outsource the job.

so weighing up best option.



#5 Re: Stromberg Carburetor rebuild V12 S3

Posted: Thu Feb 16, 2017 6:03 pm
by Whitact
Most if not all the information you need to rebuild your carbs is in the knowledge base on the forum.
Its a relatively straightforward job if you follow those guides.

#6 Re: Stromberg Carburetor rebuild V12 S3

Posted: Thu Feb 16, 2017 9:44 pm
by vee12eman
Hi Simon,

As pointed out by Adrian and forgotten by me, look in the knowledge base…


Scroll down a bit for lots of info on Stroms.


#7 Re: Stromberg Carburetor rebuild V12 S3

Posted: Sun Feb 19, 2017 7:29 pm
by Adamski
Be very careful on the outsource. I paid £600 to a well known Carburettor company in the 'Southern' part of England. Their work had left me spending hours and hours of tracking a fault that they should never have done. I have spent so much time trying to find out why my car was running awful when hot and after virtually replacing the complete ignition system I eventually found that the temperature compensators had not been set and were open at ambient. The result was that my car was running so weak that the valves were clattering and it was backfiring. It was only when I eventually targeted and adjusted them to start opening at about 50 deg.C that some kind of order was restored. I so wish that they were just screwed shut but they should have been calibrated in water or other means. I addition the overrun valves were never dismantled and were leaking vacuum through the gasket joints at diaphragm. They also were opening too early and having an effect on the mixture. My learning curve was exponential and I'm still working on the car with much better results.
My advice if the car is behaving itself self then send them away at your peril. The above two items are misunderstood and too many myths and inexperienced specialists are actually causing problems.
You might get back shiny and clean minefield of trouble.
I will do a follow up to my post of misfire when hot when resolved.