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Triumph Spitfire - Vacuum advance and DCOE carbs

I have a 40 DCOE 18 Weber and manifold that I want to fit to my 73 Spitfire 1500. What I should do with the vacuuum advance? There is no fitting on the carb or manifold for connecting the advance line. My engine is stock. I'm a novice at this and would appreciate any advice. Thank you.


As I understand that the DCOE Series carbs need a distributor with a mechanical advance like a Mallory dual point. I think the existing distributor can be re-curved but I can't tell you how this is done. If you have a Victoria British Catalog there is a short explanation in the ad for DCOE Carbs.There may be something in the archives regarding this subject.

I have a Weber DGV that performs very well on street and road. I was thinking of changing to the DCOE. Keep me posted.

Andy A
'79 Spit
Andy Anderson

Hi Michael,

I have never personally dealt with Webers, but I have been curious enough to research them quite a bit.

If you want to keep the vacuum advance intact, I believe you should drill a hole into the inlet manifold, tap it (use a tap to cut threads into the metal), and install a fitting to connect the vacuum line to. With a single DCOE, you should be able to just add the fitting and connect the line. It will behave just like the stock setup as far as how it operates.

If you are going for the best performance results, I recommend changing to an all-mechanical advance setup.

Distributorless ignition systems are the best way to go because they are the most accurate. They are also rather expensive.

Mallory dual point distributors with mechanical advance only, or a similar product will also yield excelent results. These are around $250.

The cheapest method of switching to mechanical advance is also very effective. Get a copy of the Spitfire Competiton Preparation Manual and follow the procedure to remove the vacuum unit and alter the distributor. It is not a very complicated job, and it is a great way to avoid drilling holes in wour new Weber manifold.

Just be sure not to simply remove the vacuum line and do nothing else. Your engine performance will suffer because your timing will always be a step behind in adjusting to changing rpm's.

If you have any concerns about this or anything else, feel free to contact me.

Good luck, and happy motoring,


You say you have A DCOE40. For a 1500 you NEED a single 45 or twin 40s. The size is very important and the car wont ever run well without those sizes.
The DCOEs do NOT require vacumm advance and no attempt should be made to start drilling things up.
The distributor is recurved by fitting different advance weights, its cheap and not difficult.
They are availible from Triumph Tune in the UK.
What jets, chokes & venturis have you got in it?
It must be set up correctly to run well.
Also you must get it set up on a rolling road.
Most of the horror stories you hear about DCOEs being fuel hungry and giving horrible running are from people who set it up wrong and never bothered getting them tuned correctly.

This thread was discussed between 28/03/2001 and 05/04/2001

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