FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Royce on May 06, 2021, 07:49:11 AM
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I have looked on the net and so far nothing... Anybody know where I can find the stock jetting and power valve number for a 65 4100 carb on a 352 automatic...
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Royce, I ran into this problem with the 4100 in my 390 '65 Galaxie. Are you redrilling and tapping the carbs to accept standard jets? Ford uses a different threading, so standard jets won't work unless they're drilled and tapped, and from what I could find out, Ford only used 2 different jet sizes in the Autolite carbs. That leaves very little room for tuning. Also, going by memory here, Ford didn't use standard numbering on the 2 jets, so I'm not sure it's even possible to say what jet "size" they used, at least by our standards of jetting with modern carbs. I'd have to look when I get home, to be sure, but that's what I recall.
Edit; If you want, I can pull the top off of my Autolite and test the jet size using a numbered drill. That would give you a reference on the stock jets, which is what mine has. It wouldn't be a problem since the top comes off easily without having to pull the carb.
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I was talking the Ford jets... I have not taken the top off mine yet to see what is in there but I can already see the carb has been messed with. First tank of fuel yielded 10 mpg, some something is wrong in there.. I have a assortment of the Ford jets around here somewhere.. Was hoping there was a chart available that listed jet size for each carb number like the Holley spec chart.. Thanks for the offer Doug, but maybe someone will come up with the answer without you taking your carb apart
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I have looked on the net and so far nothing... Anybody know where I can find the stock jetting and power valve number for a 65 4100 carb on a 352 automatic...
The Ford Parts Book has the stock jet sizes. It will have a power valve part number, I’ll have to look if they give a “spec” for the power valve, it’s been a while since I’ve dug into that. I can look it up for you. The parts book also lists the I.D. codes for the booster clusters too.
Do you know the I.D. number for your carb? If it doesn’t have the tag anymore the I.D. number is usually also stamped on the drivers side front leg of the carb.
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65 is too new for my parts books lol Carb is C5AF and the rest is mangled.. If you could look when you get a chance I would appreciate it
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I don't know what year it came off of, but I had it marked 352 and it has 61s in it. Because they are a different thread than the Holleys, I used to save them and when I wanted a bigger size I would drill them out. My stock 352 '63 gal only does 11 -12. I blame it on shitty gas. Make sure your vac. advance is working and throw a lot of timing at it.
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Like I said, there are only 2 jet sizes used on Autolite carbs, including the 2 bbls, so I highly doubt that is the problem. The 2 jets aren't that different in orifice sizes, so I can't see it making that big of a difference in mileage. Unless of course, since you said that the carb has been messed with, somebody already drilled and tapped them, then threw in a jet that was way off. You can check by trying to thread in a standard jet. If it threads in, it's been messed with. If they won't thread in, it has factory jets in it. Often times people forget to put in the check ball for the secondaries, and if they are opening to quickly, that can kill fuel mileage.
If you really want to 'tune' the carb, you'll have to drill and tap them for standard thread sizes. If it's a stock engine, that typically won't be needed as the 2 factory jets will usually get you where you need to be. If for performance use, it's a must.
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If they won't thread in, it has factory jets in it.
If it's a stock engine, that typically won't be needed as the 2 factory jets will usually get you where you need to be.
Unless somebody has drilled the stock jets out....like Shady..lol
Not a jab at Shady, it just shows that checking with a numbered drill will be the only true way to tell. I'll check mine tonight. I have lots of Autolite carbs sitting around, so I have both jet sizes in stock condition, if needed.
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There’s actually way more than two jet sizes - the Ford ones run from 37F - 75F just in ‘65-‘72. Admittedly that runs through all the Ford carbs, not just the 4100 series. And some more common than others, but in any case more than just two are used even in the 4100’s.
Picture from the Ford Parts Book:
(https://i.postimg.cc/Px0LYG7g/1-C98367-E-A09-C-4-B9-C-AC6-B-A245-BCF969-E8.jpg) (https://postimg.cc/dkmtcfw6)
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65 is too new for my parts books lol Carb is C5AF and the rest is mangled.. If you could look when you get a chance I would appreciate it
Well, that narrows it down to about 3 dozen possibilities lol. Is it a “1.12” carb? Just making sure. Are you sure there isn’t anything readable here? Just trying to get you the most accurate info.
(https://i.postimg.cc/qRTSRgJS/E6-F5-F4-EE-C4-EE-4660-BEF7-0-DAAA78613-FC.jpg) (https://postimg.cc/PLS2VX8Q)
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There’s actually way more than two jet sizes - the Ford ones run from 37F - 75F just in ‘65-‘72. Admittedly that runs through all the Ford carbs, not just the 4100 series. And some more common than others, but in any case more than just two are used even in the 4100’s.
Picture from the Ford Parts Book:
(https://i.postimg.cc/Px0LYG7g/1-C98367-E-A09-C-4-B9-C-AC6-B-A245-BCF969-E8.jpg) (https://postimg.cc/dkmtcfw6)
Interesting. That goes against everything I've found out and have experienced. In all the carbs I have, I've only found 2 jet sizes.
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Interesting. That goes against everything I've found out and have experienced. In all the carbs I have, I've only found 2 jet sizes.
Maybe not. It would seem that part page covers Holley and Autolite. Just going by the graphic, it looks like the Type 1 jet is for Holleys and the Type 2 for Autolite. There are more than two Autolite jets, but that assumes that is the application.
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Interesting. That goes against everything I've found out and have experienced. In all the carbs I have, I've only found 2 jet sizes.
Maybe not. It would seem that part page covers Holley and Autolite. Just going by the graphic, it looks like the Type 1 jet is for Holleys and the Type 2 for Autolite. There are more than two Autolite jets, but that assumes that is the application.
Not exactly, the numbers with the “F” after them are for the later generation 4100 & 2100 carbs. So like I said, they run from 37F to 75F. You are correct that Holley jets are listed on there too.
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Royce, I made you out a chart for the C5AF-xx 352 & 390 Ford 4 bbl carb jetting. I included the 390’s just because they’re similar and have some application overlap, but the info for the 390 Police Interceptor ones is interesting also. This is for 0-5,000 ft elevations, which would be stock. The Ford Parts Book just lists the jet number & part number, it doesn’t include the actual orifice measurement, I’m guessing that info exists somewhere, but I don’t remember seeing it. For the Economizer valve ( power valve ) it looks like they all take “kit” part number C0AZ-9A565-A. That’s for elevations from 0-5,000 ft. The “kit” includes the valve and two different gaskets. There are a couple different kits for higher elevations. I don’t know off hand what that valve equates to for a vacuum rating like a Holley power valve. At least without testing a stock one. Most people I know that race with a 4100 substitute a Holley power valve to get the variety. With those Jet part numbers on the other page I pictured you can often find NOS ones, and someone has been making reproduction Ford “F” Jets in various sizes, I’ve seen them on eBay before. Possibly available from some of the bigger carb parts suppliers too.
(https://i.postimg.cc/8c1hjgrT/0956-A13-E-E4-C9-4-E95-8648-C2-C1-A21-F1-CD8.jpg) (https://postimg.cc/YGs4sV3P)
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mine was a 2100. sorry 'bout that.
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Good info. I have a old cigar box somewhere with 2100/4100 parts in it. Have to find it and see if there are any jets.
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Wow you guys have gone above and beyond the call on this one Shout out to Kevin...I'll try to decipher that last letter on the carb I have, but it looks like the chart shows an application for 352 auto.... Next step take the top off the carb and see whats in there.. I was thinking a middle of the road 6.5 power valve should do the trick..
One other question.. I remember hearing about how guys would make a little modification so that the secondaries would open mechanically... Anybody recall how that is done.. This would be for dyno testing purposes only
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I do it with a steel fishing line leader. Works well and with the leader being stranded ss it won't break.
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Ebay has some kits to make a 4100 mechanical look under vintage mr gasket they work well i have used them for years.
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Is this the kit you're referring to?
https://www.ebay.com/itm/143882037742?hash=item218009a9ee:g:6HkAAOSwCyZf0AZu
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Thanks guys just what I need.. Dyno operators hate vacuum secondary carbs. Hard to get a consistent pull.
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Yes that is one of the kits the one with 1528 part number also has it plus one for a holley
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Holley jets are listed, number-wise, not only for the orifice size, but exactly how the lead-in and lead-out of the hole is treated. You might well have several that have the same hole size but a somewhat different chamfer configuration.
Ford jets might well be the same.
KS
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Hi Royce
There is a shop here in Denver that sells all sizes for the 4100 and 2100 over the counter. I will go by tomorrow A.M. get their address and phone and get back to you. And yes they are priced very reasonably
All the best
Larry in Denver
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Will these work?
https://allcarbs.com/product/motorcraft-ford-autolite-main-jets/
Have dealt with this place many times. Great to do business with.
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Ebay has some kits to make a 4100 mechanical look under vintage mr gasket they work well i have used them for years.
Had one of those on my 56 Ford Yblock back in the 60's. Recently I made one from memory for my 79 Ranchero. Had to tweak it some but it works fine.
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Thanks Jared.. I have worked with Allstate carb in the past.. My carb has 48s in the primary which is listed as correct, but the jets in the secondary are not numbered,, looks like someone filed or sanded the top maybe to remove a burr from an ill fitting screw driver.. I'll probably order a set just to be sure what I have.
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Will these work?
https://allcarbs.com/product/motorcraft-ford-autolite-main-jets/
Have dealt with this place many times. Great to do business with.
X2...I've also dealt with Allcarbs many times. Great service.