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  • Fiat Engine Carb upgrade

    The carb on my 2.0 Fiat engine is the original 34 ADF with electric choke, I have found a new 32/36 DGEV (with electric choke) available in the USA delivered for around £250 which I believe should just fit the current inlet manifold; has anyone done this & if so what potential teething problems / headaches might I encounter?

  • #2
    Re: Fiat Engine Carb upgrade

    Hi
    I have replaced the carb on my 1800 Fiat twin cam with the 32/36 DGV carb. An upgrade recommended to me by the Fiat twin cam guru Guy Croft.
    You need to also replace the spacer between carb and manifold. The DGV has a different shaped hole through it compared to the ADF. The spacer is thinner than the original so you also need shorter studs. You will also need to manufacture your own throttle cable arrangement (which is what I did) or get one of the special kits from someone like Webcon. http://www.webcon.co.uk/shopexd.asp?id=10491
    I fitted the carb with the fuel inlet forward facing. I am not sure if this matters so you can experiment with orientation.
    You say you have an electric choke. This was never standard fit on the ADF (Water choke) so I am assuming that someone did some sort of retro fit in the past. The ADF has a fuel shut off valve (solenoid on the side) which the DGV does not have so make sure you isolate the power cable to this properly or it could short when ignition is turned on causing sparks next to a carb which could be very dangerous.
    I chose the DGV because I wanted the manual choke as I never trusted the water based choke. You can get the 32/36 DGAV which has a water based choke. If you go electric or manual choke then you will need to remember to replumb the pipe work.
    Hope this helps
    Jon
    Mk2 SWB Marina Roadster with a 1800 Fiat Twin Cam engine and 5 speed Abarth gearbox built in 1987
    - I have no idea what I am talking about........ but my advice is always free! -

    Comment


    • #3
      Re: Fiat Engine Carb upgrade

      Aha, right, thank you Jon. Plenty to mull over there. I had assumed the ADF had an electric choke - I think my Dad told me so (he built the car back in 2001) but you may very well be right & it might have a water choke; whatever it is - it isn't manual. I was advised by 'Sporting Fiats' that the best upgrade without going to a twin carb set up was the 32/36 DGEV and that it would fit without much modification required. The change from one downdraught carb to another I think I could probably handle. I'm not that familiar with carbs myself, most things but they are a grey area atm.
      I have got a twin carb sidedraught intake manifold for the engine - from eBay last year when one came up and I knew it was a worthwhile investment but once I had it, I discovered the cost of twin carbs So just decided to keep it for a time in the future when I could afford a 2 set and then modify the side louvre wall to site twin carbs as others have done. Meanwhile the prospect of a simple change from one downdraught carb to another seems not too daunting a task & just about affordable shortly.
      However, I won't rule out a 2 set if it did come up over the winter; it'll be either or - and I'll just take my time over the cold months. The cold air feed is a problem I am dealing with atm; making a custom built air chamber out of brass sheet to fit snug beneath the bonnet and take air in from down below instead of the current set up where the current air filter sits over the ADF carb and under load it sucks the bonnet down over it so there's poor air input. Again this wouldn't be an issue if I were to move to twin carbs.

      The water based choke 32/36 DGAV; would it maybe closely resemble my ADF and make the transition simpler (assuming it is water based and not electric choke fitted)?

      Tony
      Last edited by element; 22-08-18, 09:42 PM.

      Comment


      • #4
        Re: Fiat Engine Carb upgrade

        Hi Tony
        I actually moved from the ADF to twin carbs. In my case though I went for the IDF's because they fit under the bonnet with no need to cut the body work up. I am very familiar with carbs so for me it was not a difficult job to do. Just a case of relocating the dip stick tube and fitting an oil catch tank to take the breather hose and cobble together a new throttle mechanism and job done. Had it all set up on a rolling road near me at Castle Combe race circuit (Circuit Motors - great guy, proper old school). On my 1800 twin cam I saw an extra 8-10 bhp but the fuel economy almost halved. Coupled with the issue of constant maintenance I soon (they seem to need balancing regularly) got fed up and swapped them for the DGV. Best move I ever did. You will still need to have it set up on a rolling road as the settings for the Ford Pinto (standard out the box for this carb) are all wrong. The Twin Cam is so much more efficient than the Pinto it needs totally different air jets, emulsion tubes and mixture jets to make it run well. Still produced the same amount of power as with the IDF's but with much better fuel economy and reliability. My engine has not been modified so is totally standard. I think the twins would come into there own if the engine had modified head and cams etc.
        Mk2 SWB Marina Roadster with a 1800 Fiat Twin Cam engine and 5 speed Abarth gearbox built in 1987
        - I have no idea what I am talking about........ but my advice is always free! -

        Comment


        • #5
          Re: Fiat Engine Carb upgrade

          Hi Jon,

          Out of interest what sort of fuel economy do you get? I regularly get around 25mpg from my Alfa 1750 on twin webers and had an average 32 mpg on a sedate 2 day run to Mull and back.

          Derek
          Stumbling around in the dark
          Marina based SWB roadster
          Alfa Romeo 1750 with 5 speed box

          Comment


          • #6
            Re: Fiat Engine Carb upgrade

            I looked at this:
            Genuine Weber, made in Spain, not a cheap Chinese copy This carburettor is fitted with a water operated cold start mechanism (choke), but can be supplied with electric choke unit. Please specify which type you require when ordering. Note:- Water choke unit shown in picture. Would suit Ford 1.6 / 2.0 Cortina, Capri, Escort, Sierra, […]


            ... and I emailed the site to ask if they had set one up for a Fiat Twin Cam. They say that they can set up their carbs for any specifications relative to the buyers requirements.

            My email:

            I have a kit car with the Fiat 2.0 Twin Cam engine (from a 1983, Fiat Argenta) and it is equipped atm with the original 34 ADF carb. I have been advised that the DGAV 32/36 would be a good and simple upgrade. However I am also led to believe that it needs totally different air jets, emulsion tubes and mixture jets to the standard set up (for a Ford Pinto for example) to make it run well. Is this something you are familiar with? Have you set up a carb like this for this engine type before and might you still have the record of its different components & could you do so again?

            However, the reply I got was:

            "The standard setting for a Ford 2.0 should be a good starting point".

            Given the differences Jon had talked about earlier, I decided not to bother the communication any further as the guy either didn't read my email - or he just ignored what I was saying...

            Once I have removed the 34 ADF & fitted the 32/36, how difficult would it be to get it running right myself in my garage? What would I need and is a rolling road completely necessary?

            Tony

            Comment


            • #7
              Re: Fiat Engine Carb upgrade

              Hi
              I would get the carb set by somebody who knows exactly what he is doing on a rolling road - if your "expert" says he does not need one then he is an idiot not an expert

              You can get it sorta rightish without one but compared to getting it properly set up....

              Comment


              • #8
                Re: Fiat Engine Carb upgrade

                I don't have an 'expert'.

                Comment


                • #9
                  Re: Fiat Engine Carb upgrade

                  If you do need a rolling road you could try AVA turbo. Not too handy as they are beside Glasgow airport but he is " old school " and knows his stuff.

                  Derek
                  Stumbling around in the dark
                  Marina based SWB roadster
                  Alfa Romeo 1750 with 5 speed box

                  Comment


                  • #10
                    Re: Fiat Engine Carb upgrade

                    Originally posted by element View Post
                    I looked at this:
                    Genuine Weber, made in Spain, not a cheap Chinese copy This carburettor is fitted with a water operated cold start mechanism (choke), but can be supplied with electric choke unit. Please specify which type you require when ordering. Note:- Water choke unit shown in picture. Would suit Ford 1.6 / 2.0 Cortina, Capri, Escort, Sierra, […]


                    ... and I emailed the site to ask if they had set one up for a Fiat Twin Cam. They say that they can set up their carbs for any specifications relative to the buyers requirements.

                    My email:

                    I have a kit car with the Fiat 2.0 Twin Cam engine (from a 1983, Fiat Argenta) and it is equipped atm with the original 34 ADF carb. I have been advised that the DGAV 32/36 would be a good and simple upgrade. However I am also led to believe that it needs totally different air jets, emulsion tubes and mixture jets to the standard set up (for a Ford Pinto for example) to make it run well. Is this something you are familiar with? Have you set up a carb like this for this engine type before and might you still have the record of its different components & could you do so again?

                    However, the reply I got was:

                    "The standard setting for a Ford 2.0 should be a good starting point".

                    Given the differences Jon had talked about earlier, I decided not to bother the communication any further as the guy either didn't read my email - or he just ignored what I was saying...

                    Once I have removed the 34 ADF & fitted the 32/36, how difficult would it be to get it running right myself in my garage? What would I need and is a rolling road completely necessary?

                    Tony
                    Hi Tony
                    Firstly, there is no carb supplier in the world that will guarantee that the product is perfect out of the box. There are just too many variables such as exhaust system, air filter, engine condition, fuel used, ignition system, modifications etc.. These will all make a difference to the way a carb will need to be configured. Remember this carb was originally set up to run with leaded fuel with a much higher RON value.
                    If you are going to go ahead with the conversion, which I have already done, then as I said before you will need to factor in a rolling road to get the best out of it. I do not see the point of going to all the expense and effort of changing the carb and then just "making do" with the out of the box result. You may as well stick with what you have already got. Also, you will not see that much difference in performance or fuel economy between the 2 carbs so make sure that in you own mind you are doing this for the right reasons.
                    I changed to twin IDF on mine because the original carb was knackered so I needed to do something. I did not get on well with these as I said in my earlier post so changed to the DGV (Manual choke because the water chokes will fail eventually). This was because I could not revert to the original carb. In my case I bought a cheap eBay special and a complete rebuild kit and did all the work myself. It was jetted for the 2.0 pinto which in my case was not optimal for the 1.8 TC but ran OK.

                    There is a very specific way you need to set these carbs up, so as long as you follow this then there is no reason at all why you can't set it up yourself. However, if you need to adjust outside the set up parameters then you will need to change the jets, it is just the way it is designed to be done. You can get new jets very easily but it will be trial and error and there is no way to check the fuelling under load. This is the job of the emulsion tubes to control the mixture under different driving conditions so unless you have an exhaust analyser and a good friend to sit in the passenger seat and take readings as you drive around performing these different scenarios then the rolling road is the only way.

                    Hope this helps.
                    Jon
                    Mk2 SWB Marina Roadster with a 1800 Fiat Twin Cam engine and 5 speed Abarth gearbox built in 1987
                    - I have no idea what I am talking about........ but my advice is always free! -

                    Comment


                    • #11
                      Re: Fiat Engine Carb upgrade

                      Ok, thanks for the information Jon, I'll have a think about it. I know of 2 rolling road places now, one quite local and the other down Glasgow way thanks to Derek above. I also heard about someone in Perth that does a lot of work with classic cars and carbs but don't know whether he has a rolling road set up; I imagine so. I had expected to be looking at the carb change in October but atm, it's more likely to be a 'over winter' project; if not in the Spring next year.

                      Comment

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