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8 & 10 cyl Bristol cars Type 407 onwards - restoration, repair, maintenance etc |
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carburetor 407/8
I have read in this forum in the past about replacement carburetor for the 407/8 .When I got mine it was all dissasembled in a large biscuit tin!
I have rebuilt it but unfortunately the engine will not run under 1500 rpm. Everything else is fine, timing etc. Is an Edelbrock 1405 a direct replacement ? What is the CFM of the Carter AFB ? Can anyone help? regards, David |
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Calculating CFM
The site Carb CFM Calculator
seems to give good results, which also seem to be much less than typical aftermarket carb installations. When I plugged in my 440 ci engine for my Imperial years ago, I found my original Carter carb was perfectly sized by the Chrysler engineers for the auto transmission shift points. Just as expected. Too much carburetor can deliver too much fuel and dilute the oil. Bob |
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Replacement carbs
Hi David,
I went through the carb replacement exercise for my 411, which has the big block V8. I logged the process on this web site. If you do a search on "Fuel Pump in earlier V8s" and "Bates Performance" you will find the threads. The Fuel Pump thread contains very useful information from various members, including Stefano Pasini reporting on buying a Carter 3131S that he was having shipped from the USA. You may want to ask his experience as well. I was looking at the Edlebrock replacement for the Carter AFB. Chris Browne (411) who has been down the full path of after market fuel injection, Carter and Edlebrock advised me to look at the Holly 670 cfm Street Avenger, and the reviews seem to support this. I ended up buying a custom tuned Holly 670 from Brandon Bates of Bates Performance in Waco Texas, who also agreed with Chris about it being the better carb (Brandon had both and was happy to sell me either). I found Bates on the internet, and what appealed was his bench testing included in the price. I provided engine specs and Bristol performance numbers that he used to custom bench tune the carb and makes sure it has the right stuff inside for the intended use. The Edelbrock price was $199 plus shipping, the Holly was $249. His communication was excellent, he says he ships worldwide, and the price seems fair, especially with the bench testing. As it happened, I was in the USA at the time, so I had him ship it to San Francisco ($25) and brought it home in my luggage. I was concerned about the wafting odour of petrol, but I wrapped it in many layers of kitchen food plastic wrap and then wrote an explanation on the wrapping paper saying it was new and the smell was from bench testing. If the airline inspectors opened it for inspection, it obviously passed. Brandon recommended that I go to a car parts store in the US and buy the Holley fuel lines, which I did. When I installed the Holley, I had to fashion some parts he did not mention. The Holley requires a carb spacer to clear the intake manifold on a 383 (TRD-2084 $19.95) and a Lever Extension, a transmission shift adapter since the linkage is offset on the narrower Holley (HLY-20-7 $8.25). When Bob Schmidt said he was flying down to New Zealand, he offered to bring anything that would fit into a suitcase, so he ordered those parts from Summit Racing and they came within a few days. We also bought a full set of MSD-5531 Street Fire spark plug wires for $36.95 and Autolite FRM-85 spark plugs for $1.50 each (at my local garage on the island, they wanted NZ$12 each for Champion plugs). The result has been a real pleasure. It was a bolt-on solution taking less than an hour to complete. The electric choke is great and it starts immediately. For a few hundred dollars, the car runs as it never has during my tenure. I may have the wrong electric fuel pump on it, as on test runs it does seem to starve for fuel, but that is not related to the carb. So far I have not taken it to a tuner to check the numbers. The car is not legally on the road yet as the restoration is not complete, and it has not passed its new-to-NZ vehicle inspection which is a bit of a nightmare for old cars. I would recommend you contact Brandon, provide the specifications for your small block engine and get his recommendations. He sounds like a good-old-boy car guy from Texas where the Chrysler V8 is a hot rod staple, not an exotic that commands Ferrari prices as it does down here and in the UK. He did what he said he would do, and the total cost was far less than if I had taken the original Carter AFB to a reconditioner here to be set up. It is a bolt-on solution that works. To contact him, start with email at Batesperformance@cs.com. Note his office hours are Tuesday through Saturday. It occurs to me as a community of enthusiasts that we should post our suitcase needs when other members are travelling to or from the US. With Summit and JEGs making it so easy, parts are delivered within a day or two, and can be brought back in suitcases as Bob did for me. It creates another excuse to look at someone else's Bristol and share a beer and Bristol stories. We also should perhaps do a survey to find out how many need V8 engines and 727 transmissions, and all the related parts (like carbs and fuel pumps) to see if a container shipment might not be in order. The key is to get the parts sorted the way Bates does. The horror stories of carbs for example are in wrong settings, wrong jets and other details that are easily sorted in the USA but which become major expenses, experimentation and delay as the right parts are not readily available when in the UK or the colonies. It would make some sense to find the equivalent of Bates to set up the engines and transmissions, bolt on all the upgraded parts like the newer starter motor (which I have on the 411) and then ship out a container load from US to the UK, Australia or New Zealand. Even with shipping and customs, it will be cheaper, but most importantly, the knowledge will mean these are bolt-in solutions ready to go. We have a few US based members of this forum that may be able to suggest how to set up a supply chain to assure there are no need for warranty returns. Any thoughts gentlemen? Best of luck Claude |
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Here's some more info re carb size.
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Correction to previous post
In a previous post I explained how to search the site using Google, but vBulletin changed the way the URL displayed. I deleted it from the post on this web site but anyone who received the post by email may be confused by the instructions.
I worked out a way to make it display correctly! in the Google search form use this syntax; Code:
{your keywords} site:www.bristolcars.info |
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Hello Claude,
I have had my share of trouble with carburettors, mainly due to my supreme ignorance on US carburettors (the fact that the mechanic that was working on my car was even less knowledgeable than me didn't help.) I didn't have a particularly good experience with Edelbrocks; i bought one 1403 and one 1405 and they seemed a bit 'large' for my 318. This, on the other hand, could have been a fault of other parts/settings of my engine at the time, so I guess that a rebuilt Edelbrock for $200 might be good for you. When I bought it, my 409 was fitted with an elderly and quite worn out Carter 3249S, very similar to the original 3131S but not quite the same, so I bought a used 3131S for $100 on eBay with its rebuilding kit ($40). Jim McQuay was right in saying that this kind of stuff is really cheap down there! Before I could have it rebuilt and tested I found a NOS 3131S for...$100 and I bought it, but I broke the engine before it was installed. When the 318 was rebuilt we decided to fit the NOS 3131S, of course, as I wanted everything to be as new and as original as possible. Before fitting it, mr Gordini decided to check the interior and found that it was NOS all right, but someone in the past had removed the top and put it back without considering the right assembly sequence, so needles bent! No big problem, everything in the kit was put in the 3131S and it runs sweetly as it was intended to. According to my mechanics, who are specialists in US engines, Carters are really very good for these V8s and if can, keep them. Cheers Stefano Last edited by pasini s; 23-04-11 at 03:01 PM. Reason: Missed the subscription to the thread |
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Quote:
However, once you take into account the time and cost of sourcing a rebuild kit and the time charged to do the work, it might be cheaper in the long run to just buy a new one and you may find a new one will hold it's state of tune longer. |
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I started the thread as my car ran like a cement mixer!
I found an overhaul kit on ebay (Australia) fitted it and followed exactly the sequence in the workshop manual. It now runs great (it won't stop however!) If you must go for a new carb, I would agree with Greg and go for an Edelbrock. Good luck! |