4 Barrel manfold and carburetor

After a couple of months of playing I thought I would report on the progress with the 4 barrel carburetor set up. Turns out that most 4100 Autolite carburetor(s) are very "engine specific" and are seemingly un-useable on a stock V12 ( I tried 3). The major problem is idling...they either don't idle or idle very rich and it's not consistant. Even the so called "Mustang 289" version had these problems. The design of the manifold ( open log type) may contribute to this along with emission considerations in effect during the 60's?

By contrast, the Carter WCFB('55 Chrysler) and the Holley 4150('57 Ford) both perform quite well. I choose these because of their realitive small size ( less than 500 CFM). The Carter is a little "fussy" on cold start up but smooths out quickly. The Holley is very smooth from the git-go. I really didn't want to use the Holley due to it's "leak" history but so far it really runs the best. I'm going to continue looking for a '58-'59 Ford Autolite 4100 ( pre emissions) which may work even better. I like the Booster Venturi design on these carburetors if I can just get one to run right! Lately, I rigged up a PCV system which seems to work with little or no affect on carburetion and it does draw off those V12 fumes. More later.

Dee:

The 57 Ford Holly is a great carb, just under 600 CFM. I've been running one on my 312 Y Block for years. I improved the leak and made the float adjustment easier by putting some later model float bowls on, off an 1850 600 CFM that ran too rich. I think the Holly is easier to rebuild and much more adjustable than the Autolite. Still might be worth your wile to find someone with a dyno and an exhaust gas analyzer to fine tune the jet size and the accelerator pump linkage. Your manifold looks like it may be a single plane?, making low speed tougher to adjust. PCV should help with the famous V-12 sludge build up.

Thanks for the updates.

Abe

Abe, Sorry didn't answer your question about the manifold. Yes, it is a single plane, open log type manifold and that may indeed be one of the reasons why I had so much trouble with the 4100's idling?

Anyway, here's another developement. I have since carefully rebuilt a '54 Lincoln teapot and installed it for a trial. Surprise...it runs and idles flawlessly even nicer than the Ford Holley!! I wasn't ready for this but I do remember how nice the '53-'54 Lincolns ran so I gave it a shot. Rigged up a choke/fast idle linkage utilizing the Lincoln hand throttle control. We'll see how this set pans out. I did also rig up a PCV system utilizing a PCV valve from a mid 80's 302 Ford. Very simple plumbing from the manifold vent to a drilled passage in the carb spacer. So far it seems to have almost no effect on idling either with the Ford Holley or the Lincoln Holley but it does draw off the V12 fumes. I like this arrangement as the "draft path" is mainly thru the valve chamber where most of the sludge seems to form.

What you are experiencing is that O.E. carburetors are, as you mentioned, indeed engine (actually vehicle environment) specific. Some of the variables that are considered for O.E. calibration are: engine displacement, engine number of cylinders, engine style (undersquare, square, oversquare), transmission type, vehicle mass (weight).

And the calibration has to do with both fuel and air jetting, as well as air velocity.

Good luck with your testing. Sounds like you are doing it in a very thorough manner.

Jon.

Well, my adventures with the 4100 Autolite carburetor may have a happy ending. I acquired an early version ( 1958 Ford 332) and so far it has performed as good if not better than either the Ford ( 1957) or Lincoln(1954) Holleys. I had a feeling that the early, non-emissions era, 4100 Autolite would not be so sensitive as the '60's carbs and so far that has proved correct. Small changes in orifice sizes and placement with in the carb body and venturis must be the answer? I'll do more testing to verify but I am happy that the 4100 Autolite has been vindicated. Seems "older is better" when dealing with these 12's.

Might add that the PCV system I rigged up also has no effect on idling with this carburetor.

What is the point?? Are you building a race car?? Is there a problem with your 2 barrel??

I believe the Mark I v-12 had better 0-60 than MK II hog with big Ford carb..mostly gearing I bet..

Just having some fun Jeff, no race car. The 2 barrel carb works just fine but The 4 barrel gives you a little extra boost. After testing this set up is destined for the 332 ci V12.

Peecher,

I recently aquired a 47 engine, and I'm going to rebuild it. I would like to know what all you did to your engine, especially 330 "

Ray

Ray, the 332 engine is a '42 that has been bored to 3-1/16". This is the standard bore for early Fords and I am using Ford pistons. The '42's were cored large enough that boring them this large is possible. It may be possible with early '46 blocks (2-15/16" bore) but I have heard that they had trouble casting these blocks so that is probably not an option? Other than this the engine is fairly stock with a mild cam grind, adjustable tappets and rotating valve hardware. from the pic you can see that the ford piston sits about .040" lower in the cylinder. I rather doubt that the '47 block ( 2-7/8" bore) could be safely bored this large?

I'd be interested in seeing photos of that intake manifold for the 4 barrel carb if possible, as I plan on doing the same for mine, only I like the carter AFB better, simpler, and easy to tune. I put one in my 53 Ford sedan and it works great, only very cold blooded when cool out, but once it's warmed up, the motor runs great.

Here are some pics of the manifold and carb I'm using. The Austin manifold does not come polished...this will keep you busy for a day or two as the casting is fairly "hard". The 3rd pic shows the spacer plate used to gain throttle arm clearance along with providing a port for the PCV system. The last pic shows the set on the engine.

The AFB's are a fairly wide carb and there may be some mounting adjustments necessary.

Since most flathead engines where generally restricted because of air flow, do you notice any difference with this carb, vs. the 2 barrel. I haven't had the V12 experience yet, as all of my experience is with the early V8s. I know the 8s run a lot better with split exhaust, and the larger carb size.

Peecher if that engine runs as good as it looks with that carb and manifold on it I for one would love to hear a performance report. Harry

JR, By design these 12's are fairly restrictive. Unlike a flathead Ford the end cylinders must share common intake ports. The middle cylinders must share exhaust passages thru the block. You can go in and smooth up the passages along with opening them up a bit but your limited there also.

Dual carbs really do perk the 12's up but the 4 barrel offers some real advantages. You can over do it of course by using a high cfm carburetor.

Yes, you can feel the performance gain with 4 barrel. Even when the carb is only using the primaries the engine is more responsive, probably due to the larger, "booster" venturi design. The secondaries come in more gradual when flooring it but they definitely make their presence known. The old 12 just seems to run freer. I'm testing this set up on my stock '46 but this set up is destined for use on a rebuilt, larger 12 with a performance cam.

I think success with a set up like this is in the details.

If you get the chance, if you could post a youtube video, or link, I'd like to see the thing in action, I have just a lone V12, unfortunately no car. I think the engine is the 305 12. I did measure the cylinders at 2 15/16, and the heads are cast iron with Zephyr script. I'd like to find a coil adapter, and run one or two conventional coils on the thing. More than likely I will put a 600 cfm Edelbrock carb on it since I have had the best luck with that size to engine displacement.

Sounds like you have '42 engine or at least '42 cylinder heads As far as the coil is concerned you might consider sending your LZ coil to Skips ( Ford R us) for rebuild. He "juices" them up and they do indeed give more spark. As a "pump"The V12 is not as efficient as a modern OHV engine so I think you need to take this into consideration with carb selection.