I'd check to make sure the throttle shafts aren't leaking vacuum. What you are describing is classic BBD with worn throttle shafts.
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| Author: | ap5 [ Mon Oct 10, 2005 1:15 pm ] |
| Post subject: | Dual bbd carters |
Hi guys, Im having some trouble tuning my dual carter bbd slant. The story so far..... Rebuilt carbs, new manifold gasket, no vacuum leaks, same throttle butterflies in each carb [some had same holes in each, ive mirrored each carb so they have a small hole in each].Both close the same amout and close all the way at idle the idle screws are out 1 1/2 turns but it wont idle?? I can pump the pedal and hold it at 1500rpm but if you take your foot off it stalls, revs out fine too. Is there a particular way you are meant to tune these things? Or should they just run when you put them on? Ive been told to use a vacuum guage and a carby balancer but how is this done? I'll need another person to hold the engine at 1500rpm and slowly bring it down? But do you bring it down with the mixture screws or the idle stops?? Confused. Kind Regards Nathan Sydney, Austraila. |
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| Author: | argentina-slantsixer [ Mon Oct 10, 2005 4:51 pm ] |
| Post subject: | |
You may want to check your idle air bleed size, if if revs fine and dies when you let her idle... Sounds to me like the holes ain't typical of any BBD setup I've ever heard... I'm more familiar with other kinda carbs having to drill the butterflies, like holley, hummmm holley, ... and yes, holley. Why don't you check if sticking something inside the idle air bleed can cure the idling? or maybe the hole on your butterflies is too big and it's sucking up from the boosters and dieing rich... any black smoke? |
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| Author: | ap5 [ Mon Oct 10, 2005 7:12 pm ] |
| Post subject: | |
Thanks for that, How do i check and block the idle air bleed? I'll let you know the plate numbers when i get home, it had some thing like "231" stamped on it. Ill also give you the numbers of the carbs maybe they are not really identical or compatable. Regards Nathan |
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| Author: | slantzilla [ Mon Oct 10, 2005 7:15 pm ] |
| Post subject: | |
I'd check to make sure the throttle shafts aren't leaking vacuum. What you are describing is classic BBD with worn throttle shafts.
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| Author: | ap5 [ Tue Oct 11, 2005 1:00 pm ] |
| Post subject: | |
Spot on argentina-slantsixer!!! Idle airbleed tubes mismatched. Throttle butterfly holes causing idle to high. Almost fixed. Cheers mate, Nathan |
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| Author: | cranky265 [ Thu Oct 13, 2005 4:50 am ] |
| Post subject: | bbd.. |
Nathan, I hope you are able to get your carb problems sorted out. I'm guessing you have a Valiant AP5. (I have an AP6 & a VH Charger) One thing that differs with the Aussie built cars was the the Carter carbies. Partly due to local content laws the Carter carbs were built under licence by Email. ( I'm not sure if this was the case in the 60s but was a definite issue in the 70s). These carbs built by Email were nowhere near the quality of the American produced Carter's. Chrysler Australia replaced many of these carbs while still under warranty. The best Aussie produced Carters came out on the Valiant CMs, it might pay to find one of these if have no luck with your carb. Cheers J. |
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| Author: | ap5 [ Thu Oct 13, 2005 1:26 pm ] |
| Post subject: | |
Thanks J. Im actually pretty over tring to get it to run and now need my car. The holley 465 and Cain 4 barrel manifold is going on this arvo. Im sure that although the carbs look identical they are different so I'll do some more research on the part numbers and alternate carbs. Nathan. |
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| Author: | argentina-slantsixer [ Thu Oct 13, 2005 4:05 pm ] |
| Post subject: | |
Hey nathan glad to hear my suggestion helped you out. I have been learning a lot on carbs lately, and as my new general rule, every carb I tear apart for rebuild, I ream the air bleeds, tap the holes and fit them with changeable bleeds. Great add on that might save you from having to tear it down all over again, if you learn the basics about it. I'm presently working on doing the same thing on the emulsion tubes. I work mainly with holleys, 1920´s, 2300´s, etc. By this mod you can actually even control the power valvle amount of aditional fuel going to richen the main circuit.... good luck on your car! Juan |
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