I recently purchased an original Carter AFB #3269S carb from a known reputable dealer who restores these carbs, and I have been in the process of rebuilding it myself for my 62 327/340 HP engine. The primary jets are labeled #120-161 and the secondary jets are numbered #120-178. According to info I pulled out of the archives, the primary jets are supposed to be 104 and the secondaries .689. According to an article in the Restorer CD, the primaries stayed the same but the metering rods changed during production. Also, the secondary jets were enlarged to .070. Given that the smallest jet I can buy from Edelbrock is .077 and Carbs unlimited carries .075. Can anyone tell me what size the jets are that came in my carb? Do I need to change them? If so, is there another source for these jets? The numbers on these jets don't fit the goofy Carter numbering system. Thanks in advance.
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Re: 1962 Carter AFB 3269S jetting needed
3269 S, from the ST-12 manual, Main Jet .104, Secondary .068 The carter part numbers are Primary: 120-161, so your primary is correct. secondary, 120-222. I do not find a 120-178 in my reference, but it would not be too dificult to verify the size with a pin gauge.Bill Clupper #618 -
Re: 1962 Carter AFB 3269S jetting needed
Bill, thanks for the response. I can probably find a pin gauge and determine the orifice size of the secondary jets, but where can I obtain original Carter jets? When removing the soft brass jets, the screwdriver blade deformed the slot around the jets giving me concern to re-install them. Even after soaking the jets with penetrating oil for 3 days, they were very tight and difficult to remove. Also, would the originality of the carb be too severely compromised if the jets and metering rods were replaced with Edelbrock parts?Comment
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Re: 1962 Carter AFB 3269S jetting needed
I don't see a listing for either 120-161 or 120-178 in my circa 1970 list of AFB/AVS metering rods and jets. Those tiny number can be difficult to read, so recheck them with a STRONG magnifying glass.
The .104 main primary jet is 120-404 and the .0689 secondary jet is 120-228. These were OE in the '63 OE 327 AFBs. I don't have data for the 3269S, but you indicate archive data shows these same jets were used for 3269S.
I think Clem Zahrobsky might have the 3269S tech data.
Federal Mogul now owns Carter and they still offer a limited range of jets, rods, metering rod. metering rod springs, zip kits, and other small parts. The smallest jet I see listed in my '95 vintage FM Speed Pro catalog is .071, 120P-371Comment
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Re: 1962 Carter AFB 3269S jetting needed
Thanks, Duke. I have quite an extensive catalog of old (60s) repair books and guides, but no where can I find much info on the Carter carbs. Maybe Clem will chime in. Thanks.Comment
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Re: 1962 Carter AFB 3269S jetting needed
Mark,
My orignal Carter book lists the following as OEM for your carb:
Primary jet: 120-161 (.104")
Secondary jet: 120-222 (.070")
Step up rods: 16-205 (.069"x.063")
The above was originally printed in Jan. '62
The above primary combination will give you an "EMA" (my term for Effective Metered Area), (subtracting the area of the power tip of the rod from the area of the jet) of 0.005378 SqIn. I like to work with those numbers for tuning purposes. Rather than just blindly switching components and hoping for better results, I can deliberately make a change of 1%, 2%, 5%, etc. Then the results are quantified to a measureable change.
Hope this helps. Also, keep in mind that the Carter part numbering system went through 3 variations over the years. The early ones are cryptic, but most of the later ones relate to the actual sizes. If you can't find them through normal suppliers, let me know. I might be able to help you out. (Try Daytona Carburetor)
VerneComment
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Re: 1962 Carter AFB 3269S jetting needed
Clem is at Bloomington and I don't think he has computer access until he gets home.Comment
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Re: 1962 Carter AFB 3269S jetting needed
Verne, Thanks for the info on the jets and metering rods. When I purchased an Edelbrock Performer carb for a previously owned Mustang, the Edelbrock Owner's Manual came with the carb. I have retained it as it has very useful graphs that show the specific combination of jets and metering rods that you can use. It also gives % increases and decreases over the original baseline setting of the carb. I find it extremely helpful when tuning a Carter type carb. Now that you and others have provided me with the baseline of the original 3269S carb, I can experiment with metering rods and jets to find the right combo for the carb on my 62. With the oxygenated fuel we burn in the Dallas/Fort Worth area, I believe I am running hotter than normal and may need to fatten up the fuel curve to accomodate the oxygen-rich fuel. Thanks again to all.Comment
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Re: 1962 Carter AFB 3269S jetting needed
Just in case you can't find the correct size of jets (which was my problem, as they don't make the small ones anymore), I had a old boy tell me to silver solder them shut and drill them back out with the correct size index drill. I'm sure someone will tell you that they will not flow EXACTLY correct that way, but it can get you quite close if you can't get the right size jets that you need. My car has been running around like this for a couple of years now, and it runs great!
Kevin RielComment
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Re: 1962 Carter AFB 3269S jetting needed
Mark, When you finish that work, and settle on something you feel works well, could you please post the results?Comment
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Re: 1962 Carter AFB 3269S jetting needed
I would be happy to, Chris. Perhaps Clem can shed some additional light on the subject when he recovers from Bloomington.Comment
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Re: 1962 Carter AFB 3269S jetting needed
Ten percent ethanol by volume - the max allowed - is only two percent O2 by mass, which will alter the A/F ratio by about 0.15, which is well within the range of tolerance on a carburetor.
Oxygenated fuel will not cause lean misfire as might happen on a straight hydrocarbon fuel, so there is really no need to rejet.
Portable A/F meters with an exhaust probe are not that uncommon today and the best way to get your carburetor dialed in if you think its calibration is bad, but you should correct for the oxygen content. For example with 2 percent O2 and A/F reading of 12.5 means its really about 12.65 and a WOT mixture in the range of 12.5-13.0 is about optimum.
Cruise should be stoic. or leaner if leaner does not cause driveabililty problems. The best economy A/F is about 15.5, but due to mixture distribution you probably can't get a carb this lean without driveability problems.
Rochester FI can be run as lean as 15.5 at cruise, but modern engines run stoic. due to emissions considerations as stoic. is the required A/F to achieve maximum efficiency from a 3-way catalyst.
DukeComment
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F/M lists a .071 jet,120P-371
and that is the smallest jet they list. .104 and .0689 is the correct jets for the 3269. the metering rods are .069 X .060 from my listing. the closest metering rod from F/M is a 16P-123 which is .0695 X .060Comment
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