The Stovebolt Site Forums The Shop Area Engine Shop Carter YF carburetors...newish project...

Recently I posted in the Parts Wanted portion of the Swap Meet I was looking for Carter YF carburetors for the 235 but it actually is more complicated than that. Please let me explain as briefly as possible:
1. There were no YF carburetors made for the 261. A number was assigned but never used.
2. Jerry is moving forward with his long time study/work on converting 216s and 235s into engines with 250 cubic inch and almost 300 cubic inch respectively. These will need some attention in the carburetor department.

Some of the YF models made for Ford inline sixes might work but over the past few months they've become scarce. Some of the other Chevy YF models share a throat and venturi size with the models made for the 235 but they'll need some recalibration. Yes, I'm saying some Frankencarburetors may have to be created...at least until I can get a better idea.

One problem is some of the later YF models were made with pressed-in main jets. When these wear out (and from what I've seen some wear out very badly), they are essentially throw-away carbs. Those are some of the ones I'm hoping to find. Example...the YF4371S and the YF4373S. I've learned the pressed-in main jets can be removed and new ones can be made to mimic the screw-in counterparts. There are some other differences to these which probably need to be modified. Hence the study.

Please see below some images. The first one shows a YF4371S which suffered a very wallowed-out main jet. In this condition it wouldn't have worked well at all. This jet was wallowed on both sides where the metering rod had been rattling around for a very long time. Next to that you can see where I removed the jet. Obviously not threaded. Next image you can see the little nubbin on the bottom. This forms part of the main jet well.

Now you can see in the next image the first attempt at making a replacement pressed-in jet. This mimics the main jet used in the YF2100S, the YF2101S and also the YF3211S...but sort of crudely. Only using a drill press and some sandpaper. And now the next step is to figure out what to do about metering rods. Anyway that is where the work is today. I'll be coordinating with the other Jon so that any oddball carburetor created won't be too bad, but these are going to take a few liberties.

If you find this interesting or have thoughts of your own please feel free to post and/or contact me.

Edit...I'm first looking for manual choke models but I can almost promise there will have to be some auto-choke models in here, also. I did find a YF4373S which was a manual choke pickup carburetor made for the 153 Chevy four cylinder but I think it can be made to work with a larger engine.

There's a very simple fix, one that was used during the development of the Quadrajet. Those carbs have a small spring that keeps the metering rod pressed against the jet, preventing it from wobbling (or spinning, in the case or the QJ) that wore jets out and even damaged the casting the jet was threaded into. Metering rods don't have to be centered in the jet to control the volume that goes through it.

Instead of going to the trouble to make a press-fit "jet" why not just thread the carburetor body to accept Holley jets? They're plentiful, cheap, and come in all sorts of sizes. I've got a couple of hundred of them left over from my round track racing days.
Jerry

Jerry - I mildly disagree. If one is going to thread the carb body, it should be done for Carter jets, not Holley.

A few reasons:

(1) I have thousands of Holley jets in my inventory, and virtually all of them are too small for even a 216 Carter (remember the metering rod goes through the jet, so the jet diameter must be significantly larger). If you are going to have to make a fixture for your lathe (yes, I have one I made) to machine the orifice in the jet plumb, you may as well machine the press-in jets.

(2) Carter jets of the correct range of sizes are also readily available

(3) The profile of the Carter jets is designed for the metering rod, the Holley jet is not.

As few as 10 years ago, every FLAPS in the USA stocked Holley parts (obviously, because every Holley in the USA needed parts ); but this Holley advantage is no longer true in many areas. None of my FLAPS even stock mounting gaskets today. Just as easy to order Carter jets as Holley jets.

Incidentally, many (I am not going to check them all) of the Carter YF's do have the spring Jerry described that Rochester used on the Q-Jet.

Jon

Jon G - I just did a search on Ebay; there were 157 Ford YF's, and 51 AMC YF's. About 1/3 of the Ford ones are Chinese knock-off to avoid. That still leaves about a 100 of the Fords and another 50 of the AMC version.

I realize we are talking semantics, but I don't consider roughly 150 available to be scarce.

"Scarce" is something like the Carter W-2; of which I have found exactly 3 in the last 51 years.

Jon

Fine. The project is dead. Thank you for your support.

Are Zenith 228s still available in a size to fit a 261? Seems like a 270 GMC version would be close. Those are very adaptable with various venturis and jets.... at least that was true in years gone by. I know they are expensive but we only have so much time left...

As far as I know they are, Tommy. Maybe a year or so ago somebody asked about this and Carbking provided some information, as I recall. I don't think it was as much about buying them as just some venturi size, jet information and such, however.

I don't know about the cost today. The last time I looked into buying one was around 2003 and while they were available locally at that time, I couldn't afford one then and so I doubt I could afford one now.

Cheapest way to buy a 270-sized Zenith is to buy a whole engine with one sitting atop.

G.M.C. used the following Zenith type 228 carbs on the 270:

9778, 10528, 10557, 10829, 10899, 11442, 11658, 11852, 11963, 11965, 11967, 12027, 12057, 12058, 12059, and 12496

I.H.C. had engines of displacement 264, 269, and 282 that used single barrel Holley carbs. Not personally a big fan of Holleys, but some folks like them.

Jon

It was me, I was the one that asked. I found a Zenith 228 on eBay for $400. Haven't seen many since. Like you said tommy, only so much time on this rock. I have the 11658. I plan to put it on my 58 261.

I think it’s still a worthwhile endeavor. Over the next decade or three, it’s going to take a fair bit of creativity and resourcefulness to keep these engines on the road. I’ve seen the supply of usable YF cores tighten up just in the 10-ish years I’ve owned my truck, and the prices reflect it.

Jon G - I also think the project is worthwhile; and for one, appreciate the work you put into projects such as this.

the other Jon.

Well...thank you guys very much. Okay, I'll continue and will keep the group posted.

For a real departure from my usual aversion to multiple carburetion, I'm working on designing a 3-carb setup for stovebolts, using 40 MM side draft Keihin carbs for a Harley Davidson EVO engine.

www.ebay.com/itm/285956426258?

Jerry