Club126UK
Fiat 126 Chat => Tuning & Customising 126 Models => Topic started by: Rusty's Uncle on April 23, 2015, 06:36:59 PM
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After years of planning and a few disasters along the way , not to mention the cost , I finally got to the stage where I could try a Weber 30DIC twin choke carb on the 126.(http://images.tapatalk-cdn.com/15/04/23/09e0f7171333761e89598a52418e9e5a.jpg)
Lots of problems to solve but where there is a will there is a way.
(http://images.tapatalk-cdn.com/15/04/23/c205ad40d686ca51ed2e13f3b952ac0e.jpg)
I seem to have got my jet size calculations a bit wrong so now need to sort out the running.
(http://images.tapatalk-cdn.com/15/04/23/3a55bdf31377ccccc81378977b1e30d4.jpg)
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Wow that thing is huge!
Looks tidy though, does it make much of a difference or still in the setting up stages?
Chris
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Very nice, are you going to supply it with cool outside air?
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Very little road testing so far but seems promising. Running better now that I changed the primary main jet from 1.12 down to 1.00. Might be a little too weak now so may have to buy some more jets between those sizes. All good fun :)
As for cool air a kindly Slovakian chap gave me one of those props that hold the engine cover open ;D
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It's been agony and at last after 2 weeks a bit of joy at the expense of my new top of the range timing light which blew up when I got one of the clips too close to a bare ht contact. Started with an Accuspark electronic ignition & standard coil. Switched to a 123 electronic ignition with a twin spark coil. Then switched to a totally standard ignition but still seemed to have ignition problems. So in desperation fitted a brand new Zelmot distributor with a new twin spark coil, new plugs and ht leads so no distributor cap or rotor arm. Then after a couple of problems which were caused by some sort of coating on the contact breaker points which led to an interesting moment. I was scraping at the points with a small screwdriver with the ignition on. The points cleaned up and caused a spark in one cylinder which caused a big explosion through the exhaust without the engine turning over , never done that before. Engine fired up ok now with my newly modified idle mixture screw which I can now actually adjust things are looking promising but some fine adjustments to come.
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Had a 10 mile test drive this morning and I was very pleased . Plenty of oomph when you press the noise pedal , a good steady tick over and easy around town . :D
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Shame about the Timing light, but at good cost!! ha, getting the engine all up and running.
Sounds like you've made some huge progress.
Chris
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Shame about the Timing light, but at good cost!! ha, getting the engine all up and running.
Sounds like you've made some huge progress.
Chris
Hi Chris ,
To be honest I was surprised myself how it went from non-running, rough running, loads of fumes and sooty smoke with a hint of ignition problems suspected to an engine that now runs well. I have an old exhaust gas analyser that I have never tried so hope to give that a go as I bought a collection of main jets in a range of sizes in case my calculations / guesses / advice from the guys out there were not spot on. The turning point was fitting a complete new ignition system and modifying the idle mixture screw so I could easily adjust it . Can you teach an old dog new tricks? Not sure but this is new to me and I want to understand how things work, ok you can splash the cash and go to the rolling road but that does not help when your motor packs up leaving you by the side of the road.
As the Weber 30DIC is a bit like the big brother of the 126 Weber 28IMB and is a progressive twin choke the second choke only comes into play at about half throttle. So if you can get the right set up on the first choke and idle mixture screw I think the rest is easy :)
Early days and need to resist pushing that pedal right down. Although the Weber 30DIC has had some bad press as a suitable tuning modification it has long been used on 500s & 126s. I suspect that the negative views were from people who did not get the right set up.
I believe that BV challenged me to some sort of drag race, think I might be ready now ;D
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Rusty I`m glad to see you`ve finally sorted the issues out with your DIC ;D.
It`s looking good :thumbup. When are these conversion kits going to be available in your shop?
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I seen this carb setup recently and I can confirm that it is enviably shiny 8) 8) 8)
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Very cool :). Glad its finally sorted!
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Had not tried the car for over a week but gave it a run this morning and it went very well. While I am waiting for my new timing light /rev counter to arrive I thought I would try the old engine gas analyser that I bought from a charity stall at a motoring event. After I hooked it up and got my head around the very unclear instructions I was pleased that it actually worked and how accurate it seemed to be.. The needle on the meter leant a little towards rich on tick over, well within the acceptable range.
(http://images.tapatalk-cdn.com/15/05/20/5739efb610952c44aa53c5792928593e.jpg)
A small adjustment on the idle mixture screw lowered the tick over rpm so I left that where I had set it. Revving the engine just on the primary choke caused more of a swing to the rich side which confirmed what I had expected so I will be trying a slightly smaller main jet on that choke and run a retest.
(http://images.tapatalk-cdn.com/15/05/20/b22224460c7b08f3e5e76ece5298a99f.jpg)
Once I get the best mixture setting on the first choke I can move on to a high speed test for the second choke. On the drive this morning I was pleased at the way the engine ran around town and on a modest throttle it was almost like a standard carb but out of town the noise pedal really works.
(http://images.tapatalk-cdn.com/15/05/20/d1904e7aaf1110eb124c1321ab308db3.jpg)
So if you see one of these going cheap they do work.
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looks like a good pice of kit.
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Very nice, I wonder what kind of o2 probe they require. Whether they are wideband or narrowband :). Certainly like the look of the analogue setup compared to todays digital wideband afrs :D.
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Very nice, I wonder what kind of o2 probe they require. Whether they are wideband or narrowband :). Certainly like the look of the analogue setup compared to todays digital wideband afrs :D.
Not sure if I can help you there as I am not sure what that means. Fitted a 1.05 main jet on the primary choke this morning. Down from 1.12 then went for a 20 mile drive. All went well with the running and no loss of performance or flat spots . Put the gas analyser on when I got back and the needle swung just towards the lean mixture but still well in the acceptable zone. On half throttle the needle swung right of centre in the rich zone but again within the acceptable limits then outside that on the overrun for a brief period. Suggests to me that I can go a tad smaller on that jet so I will save that for my next run :)
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Took the primary main jet down to 1.00 and the car seems to run fine. The readings on the gas analyser were good and made a minor adjustment on the mixture screw to compensate on tick over. Going to stick with this now to see how it goes and get some fuel consumption figures. :)
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I am back on the carb conversion case as I have a couple of rebuilt twin choke Weber 30DIC carbs along with all the necessary parts to put together a kit if anyone is interested. So if anyone is interested and are considering tuning an air cooled engine let me know. Words of warning, just going for a bigger carb is a waste of time unless you are doing other tuning mods and also the parts are not cheap :)