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Jetting a 32/36 for a 1600

Discussion in 'Modified Alpine' started by Arschbrand, Feb 15, 2017.

  1. Arschbrand

    Arschbrand Donation Time

    I have fitted a 32/36 DGV Weber to a 1600 as I am currently rebuilding the 1725. No need to say that it is way too rich. Has anyone an idea which sizes would suit?
     
  2. ceecpa

    ceecpa Donation Time

    I have a .040 over 1725 with a breathed-on cam and I'm running the original main jets in my 32-36 but I changed the idle jets to 0.60 on the primary circuit and 0.55 on the secondary circuit.
     
  3. pruyter

    pruyter Donation Time

    I have installed the so called Webcon conversion on my Rapier series IV which has an original 1592 cc engine. This conversion exists of a Weber 32/36 DGV 5A carburettor and the special manifold which is developped by both the Sunbeam Alpine Owners Club in the UK and Webcon. Also included in this set is a plenum, an air hose and a K&N air filter.
    The carburettor comes standard with the following jetting:

    Primary main jet 140. Secondary main jet 135
    Primariy air correction 165. Secondary air correction 160
    Primary idle jet 52. Secondary idle jet 50
    Primary emulsion tube F6. Secondary emulsion tube F6

    I guess you don't have the special inlet manifold and that means that the "bridge" which is a part of the this manifold is not needed with the Weber. In order to come a little bit closer to the special inlet manifold I advise you to remove this bridge. This bridge goes with the dreadful standard Solex carburettor but is not needed when using the Weber.

    Oh and by the way the engine of my Rapier goes like a dream with this set up!

    Regards,

    Peter
     
  4. Tom H

    Tom H Platinum Level Sponsor

    Arschbrand, Peter assumes you have the same jets as his, but it would help if you can confirm what jets you have in the carb now. It seems the numbers he describes as "standard" are about correct for a 1600.

    Tom
     
  5. pruyter

    pruyter Donation Time

    Hi Tom,

    in order to eliminate any misunderstanding: the jets in my Weber are the standard jets if one orders the Webcon conversion as offered by Jerome Senn (London UK) who acts as both a Webcon dealer and the representant of SAOC.
    When I asked Jerome what jetting was used with this conversion he nearly "bagged" me not to alter this jetting, because this jetting is the result of years of development of the inlet manifold.
    In developping this conversion the Alpine of Jerome, a series V with a 1725 cc engine, was used. So to be precise: this jetting suits a 1725 cc engine perfectly and as it has been experienced it suits the 1592 cc engine as well.

    Regards,

    Peter
     
  6. Tom H

    Tom H Platinum Level Sponsor

    Hi Peter, Thanks for the clarification. When your original msg said "standard" I wondered what "standard" this was. As I said, I think these jets you list should be good for Arschbrand.

    By the way, when you mention a "bridge" I am assuming you are speaking of the material in the center of the carb opening on a stock Solex manifold, the material that makes it two separate holes. So do you think it would help in some way to grind / cut away that bridge? My assumption has always been that it did not matter and that it was just a manufacturing simplification to make the manifold with a single oval hole.

    Tom
     
  7. pruyter

    pruyter Donation Time

    Hi Tom,

    The reason why I advised to remove the bridge is that this bridge is not existing in the special manifold and is in fact an obstruction. By removing this bridge the manifold resembles the new one a little more than now.
    I was informed that the bridge was implemented while it suits the standard Solex better, but perhaps I am mistaken....

    Regards,

    Peter
     
  8. RootesRacer

    RootesRacer Platinum Level Sponsor

    Also keep in mind that the main jets also have a direct relationship to the size of the venturies which varies from carb model to model since most 32/36 carbs were developed originally for manufacturer specific applications.

    Newer 32/36 carbs for the aftermarket usually have 24 and 27mm venturies.
     
  9. alpine_64

    alpine_64 Donation Time

    Peter, the original rootes manifold has the individual ports to match the throats in the solex carb. When people use the Weber on that manifold if they had a version with the same size throats as the solex it would be fine, but if, as often the case, the throats are slightly larger in the new carb you should port match to the carb or it will restrict flow.

    An easy solution is the total removal of the separation, no port matching and quicker/easier . The current webcon manifold has the single open intake throat as it allows for multiple carb options without restriction allowing greater selection for the purchaser.. same reason that in the 60's on the f4b edelbrock went from 4 throats to 2 then 2 with a notch to balance flow.

    All the aftermarket 2bbl manifolds for rootes motors in period, c/t , manglotesi, lynx etc and more recently Peirce have just a single throat .. so it's not a new thing introduced on the webcon product.

    Another thing to consider is a thermostat spacer , the original is a fibre type, but a plastic pholenic spacer would work well to prevent heat soak in the carb.
     
  10. pruyter

    pruyter Donation Time

    Hi Michael,

    Thank you very much for your information, I wasn't aware of the details regarding the separation.

    What interests me even more is what you say about the spacer. You mention a thermostat spacer i.e. a plastic plolenic spacer. I haven't heard about such a spacer before. Do you have any idea where I can buy such a spacer that suits the Weber 32/36?
    I am very interested in this item, because I noticed when the engine is very hot that the idle is affected in a bad way. The only thing I noticed that when I spray some brake cleaner near the top of the Weber that the idle increases and that gave me the idea that the topgasket could be leaking although the Weber is new and not more than about 500 or 600 km were driven with it.
    So do I have an air leak or is heat sucked up by the Weber? It could be worth trying such a spacer as you mentioned....

    Regards,

    Peter
     
  11. George Coleman

    George Coleman Gold Level Sponsor

  12. Bill Blue

    Bill Blue Platinum Level Sponsor

    I think "insulative" would be a more apt description of the spacer. A good substitute can be fashioned by making several gaskets from paper gasket material and stack them to a height of 1/4" or so. At a minimum, it would determine if heat is a problem.

    Bill
     
    Last edited: Feb 17, 2017
  13. alpine_64

    alpine_64 Donation Time

    Peter, George has given you a few sources for getting a spacer, as mentioned the originals were a fibre/ wood type. You could make one quite easily, from an appropriate platic or timber.

    I think they were primarily to deal with heat soak after shutting down so that there were not hot start issues which the cars can be prone too, but it would also help a little with idling in hot conditions.

    In regards to your specific case, if the idle gets tough when the engine is hot I would suspect heat soak issues, it could be from under the carb or your fuel line routing.

    However I'm a little confused by your comment about spraying near the top of the carb increasing idle speed. That is a sign of a vac leak BUT where are you spraying it? If you are spraying a controlled amount at the joint between manifold and base of the carb then yes it indicates a leak.. but I'm surprised it's not an issue all the time, unless the heat expansion is opening a small gap. If you are spraying round the top of the carbs near the throats inherently it will get in and increase idle speed.. can you be more specific?
     
  14. pruyter

    pruyter Donation Time

    Hi Michael,

    I have been searching for the cause of this idling problem a long time and just the day for the car went in the garage for a hibernation I sprayed the brake cleanerat the side of the carburettor just under the plenum to which an air hose is connected and then the revolutions of the engine rised.
    Spraying at the base of the carburettor had no effect at all.
    I have to investigate this problem better then I have done up to now.
    And yes the problem only occurs when the engine is very hot.
    I asumed an air leak (possibly the top gasket), but your idea of a special spacer against the heat made me think that heat could be the cause of this idling problem....
    Anyhow I appreciate it very much that you and the other forum members are coming with suggestions!
    Thanks you all!

    Regards,

    Peter
     
  15. Arschbrand

    Arschbrand Donation Time

    Thank you! That was helpful
     
  16. pruyter

    pruyter Donation Time

    You are welcome!

    Regards,

    Peter
     

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