OK, small 260 with a Ford 4V intake, Comp Cams Hyd. cam 212/212, automatic and stock exhaust.
Here's the problem. When starting off, as from a stop sign, rather slowly, the engine takes the gas then hesitates.
Not an accelerator pump hesitation as this happens after the pump has shot it's gas. After checking a few things, I started it up, put it in drive, then slowly increased the rpm. At around 850/900 rpm the engine begins to run rough due to what I think is a lean condition. I then hooked up a vacuum gauge and did the same test. Same result, 850/900 rpm rough - 12 ins. vacuum. As I increased the rpm the roughness [lean] condition remained until the vacuum reached about 8.5 ins. and then the roughness went away. This was noticeable as if the power valve had opened.
I've played with the timing - no change, double checked the carb and transition circuits for cleanliness, tried slightly larger jets and no change. My thought now is to go with a Holley 10.5 ins. power valve, as I have tried everything I can think of. I don't want to cover up something with the Holley power valve, so any ideas would be appreciated.
Rob

And what is your application.

Thanks

Bill White

Thanks, Bill - 1963 Ford 260 engine, 64 C4 trans., 3:25 gears. This is a rebuilt engine with four thousand miles. Runs excellent, except for this problem. I have put up with this "lean" condition as it does not really effect the driveability except as noted in my first post. I was able to mask the problem with the accelerator pump for driving around, but if I jumped on it, it would bog. In truth, I didn't realize it was a lean condition until the other day when I decided to correct the problem.
The tag on the carb reads C6PF H and A 8023. It is a 1.08 carb. This combo is in a 1963 Rambler American 220.
Thanks, Rob

of what you think it is.
I think you are overcarbureted, your are describing the classic signs of overcarburetion. That bog is from your transitioning from idle to cruise or acceleration curcuit.

That C6PH-H is a VERY common carburetor, It is a 1966 replacement carb that was used to replace all 4100's from 1966 up through even the early 80's from ford dealerships.
Unfortunately it is based exactly on a 1966 Fairlane 390 GT california emmission carburetor. When Ford was looking for something they could use for an all around off the shelf replacement, at the time this was the most generic all purpose carb they could find. The problem with this carb is there really no such thing as the all around perfect carb and what ends up happening is it trys to hard to be the best for all and ends up being nothing for nobody.
It is a 480 CFM but it also was designed to flow for the FE engine. And in your case I believe this is causing your problems.

I have seen this problem OFTEN. And now what is exasperating your problems is you have covered it up to get it to run.

So what can you do,
Well first your application is close, that 63 rambler and a 66 fairlane although a bit bigger are probably pretty close in weight. The real problem is that tiny 260 which doesn't need a whole lot of CFMs to feed it. You did not mention any mods your engine may have had but the 480 CFM in even overkill when it comes to this engine. My guess is you are not doing a whole lot of top end with this package (although the idea of a 63 rambler at the drag strip is sick in a real good way but I have been seing a counselor for this problem :o) ) so you are really wasting any advantage you could get from this carb.

That being said (and since anyone swapping a ford 260 into a rambler obviously suffers from some of the same ailments that I have), I would first Re-bench set this carb (rebuilding it if you haven't done this in the last year since that will cause you more grief if you don't). When you re-bench set this carb use the 1966 Fairlane california emission settings. Check the jets and make sure you are at least at the minimum at the correct jets. Personally I would back them down at least one and probably two. THIS IS WHERE THE PROBLEM STARTS, It is the transition from the idle to cruise that it causing your overcarb situation.

See if that helps your situation, the next step would be to limit the accelerator pump to the minimixe the shot it is seeing. A few other things that could help is to bump up the timing and also to bump up the idle just a bit to help get that fuel flowing and your RPM's up before you start transitioning. Since what is happening in an overcarbureted situation is overrich fuel is being dumped in the manifold and there is no velocity to help distribute it to the cylinders.

One more thing that can help is to put a larger spacer on the manifold, again you are trying to increase the velocity and the response of the carb.

Ideally you should be looking for a 390 CFM holley 4 barrell which would be ideal for this application.
The ultimate killer app for this would be a large two barrel such as a 1.14 or even possibly a 1.21 if you have the mods to support it.
Best of all worlds, economy but performance when you wanted it.

Good luck, Hope that helps.

Bill White
White Automotive

WOW! That's a lot to digest. OK, I heard what you said. Makes sense, so to prove or disprove "my" thoughts, I warmed up the engine, put it in gear, gave it throttle to around 900 rpm, had the roughness, then had my son dribble some carb cleaner in the carb. Low and behold no change until he kept increasing the amount. No it didn't straighten out the problem, it just went richer and ran even worse. So you are correct - just the opposite of what I thought. Now let's get to the other stuff. First off, I do have a problem with putting a Ford motor in my American. I've tried to stop this affliction, but I can't help myself. Who is your shrink? Second - 66 Fairlane "GT" 390 motor with a 4100. Even California smog? I thought all Fairlane and Comet GTs came with a 635 Holley. At least my brand new 66 Comet GT came with the Holley [East Coast].
Back to my 260. It is bored .020", has a Comp cams 212/212 cam, stock 63 Comet exhaust manifolds [2' exhaust / Flowmasters], 75 Granada heads, standard Pertronics ignition and 8 1/2 to 1 compression. With 1/2 tank of gas it weighs 2520 lbs. Green Dot C4 with 3:25 gears.
While I understand your comment on too much carb [in total], with a 1.08 primary bore, isn't that portion of the carb smaller than or equal to the 2100s you listed. And while I have a rich condition during transition, why would a 2V be any different?
Just FYI, I have a 63 Comet S22 with a 63 289 block, 302 crank etc. It has 271 HP style solid cam and tripower almost like the Pony Carb setup that I did myself. I has been running great since 1998.
Yes, I have rebuilt the 4100. By looking at the plugs, it is running about as lean as I want it to. Delivers 18 mpg on the highway.
Remember, the driveablilty problem occurs after the accelerator pump delivers it's load. Based on what you have said, the carb needs to deliver less transition fuel - right? If correct, can this be done? Different venturi assembly or even close off one of the transition holes? Just thinking.
Send me your email address and I will send you some pictures of the American.
Thanks, Rob

For a while I had been seeing a Dr. Shelby, he didn't solve my problem but he was very sympathetic............ Now I have kinda been on my own for awhile....... The problem kind of comes and goes......

In 1966 some of the GT's did come with the 4100, it was supposed to be the california cars ,but of course with FORD its never that simple or easy.

No, I think you are close, the only really problem is that carb you have is not a "normal" 1.08, it is a california emission carb normally intended to be feeding a FE engine. If you had a normal small block 1.08 I am willing to bet your 260 would not be having this problem.

You never mentioned which jets you are running. But the stock jetting for that carb should be 48 for the primary and 67 for the secondary. Check and see what you are running but you could go at least one to two jet sizes smaller. No more. That will take care of one side of the transition.

For the other side you need to see what you accelerator pump setting is at. It should be at the inside hole on the pump lever and the number 3 hole at the throttle. IF you have it there then back it down to the number 2 hole. And again you can cheat just a bit by bumping up your timing 1-2 degrees, and/or bumping down your idle mixture screws 1/4 turn but you shouldn't have to do that.

As far as the two barrels, they are rated differently on CFM as compared to the 4 barrels, so you really are not comparing apples to apples. A 1.14 two barrels is not bigger than a 1.08 four barrel. Four barrels are rated at a different pressure drop since there is more volume flowing through the entire area. Whereas one and two barrels are more restrictive so they are rates at a much larger pressure drop.
Bottom line the 4 barrels since they are less resrictive flow much more air flow and consequently make overcarbing very simple. I often see people who have gone from a large CFM two barrels and placed a small four barrel (say 480 cfm two to a 500 CFM four like on a chev 305 truck going from a rochester two to a holley 4) and having the exact smae problems you are describing. It hard from some people to get away from "Its only 20 more CFM"

The differences between that 271 HP 289 and your 260 are huge (well maybe not your 260) but that 289 was really a wolf and not even very well cloaked in sheeps skin. It really is a pretty well built race engine. And consequently was designed to reach and RUN at 8000 rpm.

Most small block, yours probably included, rarely see 6 grand. The difference? That little K motor needs those large CFMS to keep it happy as the R's go through the tach. It needs that 600 HIPO small block carb (WHICH BY THE WAY WAS ALSO A FULL RACE CARB AND NOT THE SAME AS A RUN OF THE MILL 600 CFM FE CARB WHICH FLOWS TOTALLY DIFFERENT FOR THE FE ENGINE).
Your CFM requirements are a modest 450CFM which is even a far cry from the 289 small block 480CFM.

CFM requirements are a mathematical equation based on the real laws of physics based on how much air your engine can digest.

Hope that helps.

As you can see my Dr has progressed me thru the later stages of my problem..........

Bill White

Yes, I am aware 2Vs and 4Vs are rated differently [1.5 ins. vs 3.0 ins.]. Also, 70% of the 2V rating would about equal a 4V rating. I did the calculations for my 260 at 5200 rpm [about all you can get out of the stock exhaust manifolds] and at 85% VE the cfm needed is 332. A long way from 480!! However, according to what I have been able to find out [correct me if I'm wrong], the 1.21 2V is rated at 351 cfm "2V" and at 70% for 4V rating, it would be 246 cfm. I mention the 4V rating so that we are trying to talk apples to apples. I know what you said about the California 1.08 flowing differently, but 1/2 of 480 cfm is 240 cfm and the 1.21 flows 246 cfm [4V]. ON "paper" there should no difference between the two at a constant 900 rpm in drive, which is where the problem occurs.
Can you educate me on the differences between the Calif. 4100 and a "standard" 4100? Also, I have #48 jets primary and I will see if I have anything smaller. If I decide to stay with this carb, should I reduce the size of the secondary jets as well and if so how small?
I would like to talk to you about the above. If that is OK, send your # and best time to call to my email address rbrainard01@comcast.net
Thanks, Rob