Hello All, I need advice, and sources for older BBD Chrysler Carter carburetor jets....to compensate for HIGH ALTITUDE motoring..... I am preparing a 1954 Kurtis 500 for the Colorado Grand. The car's carburetion is currently set up for sea level... The car will be experiencing 7000 feet to potential 12000 feet elevations along the tour route... We want to be prepared for adjustments for these elevations... Looking for range of leaner carburetor jets to adjust as needed....to lean out mixture as required...... 1954 Kurtis with Desoto 291 ci V8 Hemi. T10 top loader transmission, Ford rear end. Currently running two 2 barrel B&B Carter BBD of the 1950 vintage on an Edmonds intake manifold. Tags are missing from the carburetors..... The main jets are currently 120-213s (Front carb), and 120-215s (rear carb). The metering rods appear to one diameter all along the length(not stepped). Front pair of metering rods measured at 0.0263 in diameter. Rear pair of metering rods, measured at 0.0301 in diameter. The jets are the OLDER style long, with a fiber washer at the base. Any sources for Carter Jet numbers 120-211, 120-212, 120-209, 120-211, and 120-305...these being the next 5 leaner numbers...as candidates? These are all the same 0.036 in orifice, but with lower CFM ratings.. AGAIN, need the longer style with a fiber washer at the base.... Going in the right direction? Perhaps a new set of carburetors...with newer jet availability? Push the car up the hills? Thank in advance Paul
Paulvv , Just a thought out side of the box , Would you be willing to install a good wide band O2 gauge ( to monitor air fuel ratio) ,then Make a way to manually ( like a valve on a garden hose or something similar in how the valve works) controlled air leak when needed a leaner jet ,, Just a thought or Ideal if not able to find the leaner Jets . This has been done in some forms of Racing threw the years.
Another outside the box...our airplane restoration group has a Bede 4 that was donated. It has a V6 Chevrolet in it, supposedly a Marine engine. The carburetor is a two barrel with a fairly large squarish flange. It doesn’t appear to have a float chamber but has a section added between the inlet side of the carburetor and the main body that is push/pull cable controlled and is in fact the mixture control for leaning at altitude. There is no name I have been able to find anywhere on it. Perhaps some research on your part between the marine people and some fly boys might come up with an answer. Bede has a Florida based tech center that helps those building their kits. Various engines can be used. That might be a place to start.
If in fact there is no float bowl, I’m wondering if this carb has something trick to handle the rolling and pitching of a boat, something akin to a 2 cycle. I will be at the hangar Friday if you want a picture, let me know
Hello, 28dreyer 19Eddy30 Thanks for the "out of the box" suggestions...!! Sometime we need to go back to the basic theories....to come up with new solutions... I am going to research that approach in parallel to jet substitution.. Namely, a "controlled" air leak... Keep those suggestion coming! Thank in advance Paul
Paul - some folks are just a glutton for punishment You asked for advice: CHANGE TO DIFFERENT CARBURETORS! Your rear carb has a tag - 2685s. This corresponds to a 1958 Chrysler type BBD. You need some information on the jetting in these things! The jets come in different threads, different guide sizes, and different volume flow rates. You mention an orifice of 0.036, but different CFM on jets. Not exactly correct. The 0.036 you are measuring is the guide diameter ONLY for rods of 0.030 diameter. The different jet parts numbers you mention all have different orifice sizes and a different flow rate. For the 2685s (rear carb), standard jetting is 120-215s (378~386 cc), 1 size lean is 120-214s (356~364 cc), and 2 size lean 120-213s (337~343 cc). Changing to a different diameter rod (your two carbs have different diameter rods) changes the cc flow rating of the jets. Unlike Carter's real carburetors, the rods, as you mentioned, are the same diameter all the way (no steps for different vacuum). The rod is either in or out of the jet orifice. The guide centers the rod so it will slide in and out of the jet. Without knowing the tag number of the other carb, virtually impossible to look up specifications (no offense meant, but NOT going through 800 carburetor blueprints to look up the sizes you measured ). In the for what its worth category, IF you had two exactly matched carburetors of this type, your quest of adjusting for altitude (at least efficiently) would be exceptionally difficult. With two non-matching (one unknown) carburetors, the exceptionally difficult changes to virtually impossible. I have the parts for sale (they are not cheap) but I truly hate to take a bunch of your money for a project which has very little to no chance of success! My choice would be a pair of Carter WCD's. Second choice would be either Stromberg WW's or Rochester 2G's. With the Carter WCD's, you leave the jets alone, and re-calibrate for altitude by simply changing metering rods, which may be accomplished without disassembly of the carburetor. In fact, to prove a point, I once changed a set WHILE THE ENGINE WAS IDLING! The metering rods, rather than the jets, have different calibrations. Plus the WCD rods are 3-stepped, so you control metering at three different values of vacuum, rather than only two. The WCD carbs use the same jets as the standard AFB jets, and AFB vacuum piston springs may also be used. But if you change, get two exactly matching carbs to start with. What is the emoji for a bottle of aspirin? You are going to need them on your present course! 573-392-7378 (9-12, 1-4 Mon-Tues central time). Jon.
Jon, THANK YOU.... I totally concur... New direction...NEW CARBURETORS.... Have 3 weeks to dial this Kurtis in..... AGAIN...THANK you.... Best Regards Paul
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