Yes, the hard part of a web search is figuring out which bits of data to believe 'cause you will almost certainly get conflicting results. I try to read several posts from the people whose comments are the most significant as sometimes I get a sense from them of whether or not the person knows what he's talking about. And, I'll admit that I'm biased - I sometimes base my beliefs about a poster on the way s/he writes, spells, and uses grammar - or doesn't.

I do agree that the engine should warm up more quickly with the valve open as there would be flow. Otherwise the once-hot gas would cool as the air/fuel mix passed through. But, I also agree that the valves look to be prone to sticking. Mine is so sooty that it is hard to believe it would work. And, we all know that EGR valves stick, either from the heat or carbon or both.

However, I've recently been told on this forum by Franklin2, a very well-respected gentleman, that you should not block off the heat passages completely. He's tried it and said the driveability suffers badly.

 

Exactly. Just because you found it on the Internet then it must be true, huh?

Search around on the 'net and you can prolly find something saying anything you want - the Earth is flat, water is dry, whatever.

This is why I like this place; there are some guys here who have been working professionally in the industry for decades and who share their knowledge here, and that can generally be backed up with some sort of official documentation.

So, give it some time, and we'll get it figured out.

That being said, I discovered something in the image I submitted in Post #13 above.

That device is listed on the RH side of the manifold (now shaded as red) with a Part Number of 9G464:





The parts book sez:

E3TZ-9G464-A VALVE ASSY. (INTAKE MANIFOLD HEAT CONTROL) Fits 83/87 E-F100/250 & Bronco either with a V8 302 or with the 351W with the 4V carb. Use with gasket 9E486. Text Section 94, Pg. 40.

What we haven't figured out for sure yet is what it's for, what it does and when. I'm sure the engineers had reasons for its existence, and I'm quite honestly impressed with what Detroit was able to accomplish using only vacuum & temperature, no computers to help.

Anyhow, I think we'll get it figured out.....

BTW my info is coming from the 1980-89 Ford Parts Catalog and is available on CD from www.hipoparts.com. Some people here besides me also have it (NumberDummy has all this stuff on paper & microfiche).

There are a couple other guys around here who are what I call "industry experts," too....

 

Ctubutis - 'Tis interesting. Apparently the catalog isn't always correct. Or, we shouldn't read it as absolute. I say that because my '85 4V manifold did not use 9G464 - in fact, it doesn't even have an opening that would allow its use, as shown in the pic on Page 3 of my thread on Refurb or Rebuild. So, the statement of "Fits 83/87 E-F100/250 & Bronco either with a V8 302 or with the 351W with the 4V carb" apparently wasn't meant to mean all 351W's with the 4V carb. And, by the way, the '85 HO manifold is an E4 so it was a fairly new design.

So, the factory used the 9C869 valve both with the 9G464, which is probably where the carb got its hot air for the choke, and without it. In the latter case they installed an electric choke, as on my '85 HO. But, if it was truly for heating the choke, why use it on a manifold that didn't even have a well for the choke stove? Unless they also used it for some reason with the EGR valve that does get its exhaust from the heat riser passage on that manifold?

 

Correctomundo!

Look at the text at the bottom of the image:

MANIFOLD and RELATED PARTS - W/O E.F.I. - TYPICAL

Notice it doesn't say ABSOLUTE because it would be VERY VERY VERY difficult to produce such a document as there were SO many variations made.

Cripe, you've got the CD, go look in the Text section, Sections 93A and B.

Look at all the dang Calibration Codes that were possible, and the associated mixtures of parts & components used and to where they were applied.

Do you honestly expect there to be pictures of each of those?

Ha!



I have no idea and am not even reading that, much less trying to comprehend and understand it - too much caffeine right now, it's Friday and it looks like a really nice day out and I wanna get away from the damn computer.

 

I did finally "share" the DVD drive so's I can peruse the catalog from my Mac in the evening while watching baseball. So, I'll take a look this evening - assuming I'm not still out here w/Ray1986f150 doing A/C work.

Speaking of "still", why are you? After the rain and hail yesterday, and the impending work schedule, get away!

 

Part number 9G464 sure looks like what I have in front of me.

 

You are absolutely right. I'm holding mine up to the screen and there's really no mistake - the flapper valve is 9G464.

So. what is 9C869? I think ctubutis told us in a previous post, but I haven't found it. Am busy w/something else, but will look at the catalog later.

 

Well I got an answer!!! I always laughed at this one particular website that you pay for people to answer you questions, but I finally decided what the heck. It actually worked. Here is what he said below:

On earlier engines the exhaust crossover port was always open, it allowed exhaust flow to heat the intake plenum below the carburetor to promote better fuel atomization when the engine was cold. By 1985 (the last generation of 302's before EFI), lean fuel mixtures and changes in fuel blends had resulted in a situation where the heat under the carburetor could create percolation (fuel boiling in the fuel bowl of the carb) or vapor lock. So the valve's intention was to close off the crossover on warm engines to prevent this from occurring. My suggestion would be to try to find intake gaskets that come with metal restrictor plates that can be used to either partially of completely block off the passage. The hot engine fuel concern is much worse than the effect on cold engine performance in my opinion. If I remember correctly, the EGR is fed by this passage, so you would want to only restrict one side, which would be the same side that the valve is located on (driver's side? if I remember correctly), that way the EGR valve will still be fed with exhaust.

 

We had all of that worked out except the bit about percolation. In fact, I knew that the fuel blend had changed to make it more volatile, but didn't tie that with what we knew. Duh!

However. I'm not sure I agree with his suggestion. If that flapper valve works, and mine still does, why not clean it and put it back in - along with the temp-controlled valve that would give the flapper vacuum only when cold since I think it is closed when it has no vacuum. That way you could actually use the gaskets that have openings for the exhaust but still block it off with the valve. If you don't like it pull the vacuum and let it close. But, at least you have some control since getting the heat if you block one side will require pulling the intake manifold.

 

Well, remember I am replacing the intake manifold and none of the new ones offer a location to insert the valve. I was thinking about fully blocking it just to be safe, but living in Ohio I guess I could have problems in the winter potentially. I followed up with the guy and he suggested based on my location partially blocking it. I wonder if there is any way to identify if your fuel is starting to boil in the bowl. I got to think it would start acting funny. I guess when I get this thing back together i will have to keep an eye on how its running in the summer.

 

Oh yes, I forgot you are switching manifolds. My bad, again. Getting good at that.

Go to my thread and read Franklin2's post on Page 3: https://www.ford-trucks.com/forums/1...rebuild-3.html He always knows what he is talking about, so I take his advice very seriously and he doesn't think we should block the passage off.

 

It looks like you guys already figured it out.

I've had a long work weekend...

As you found out It's basicly smog crap to get the engine to operating temperature faster, and the valve is to eliminate overheating of the intake and shut it off after it's warm.

The 300 has a simular device in the exaust manifold. A spring that moves a flapper back and forth to alow heated exaust to warm up the intake and shuts off the heat to keep the intake from cooking.

Bad things happen when this system malfunctions.

The new performance parts won't have this crap on it for a reason. It will just take longer to warm the engine.

But it's not 50 state legal either... if that's of concern.

This is different system to the choke heat tube and stove. If the new exaust manifold does not have a place for the tube to connect, you can wrap a piece of tubing around a header a couple of times. This should provide enough heat for the electrically assisted thermostatic choke to operate normally.


Oh, and for your information: C1 is the engine plant code of manufacture on the calibration lable. Cleveland Engine plant number one. This is where the engine was assymbeld.

302 engines are Windsors "for american trucks".

 

Explorer - Thanks. We had a lot of help from Chris, and Blue even got some professional help - for his truck.

 

But, nevertheless, thank you for chiming in!

I have a question about something that was brought up, that being that BOTH of those devices (in the pic) were sometimes used together? I have never seen anything like that in real life and my first suspicion is that it was one or the other.

Maybe I misread from reading too fast?

BTW to the OP this should help you with posting pix inline:

User Gallery & Picture Display Help - Ford Truck Enthusiasts Forums

Basically, host 'em on some hosting site, then find the Direct Link to the image, copy that, then paste it into the Insert Image button on the Advanced editor.

 

Gary, et all, I have a 1980 400cid, mechanical choke, thermostatic air cleaner, everthing is hooked up and working however the heat shroud around the exhaust manifold is missing. Ive looked everywhere (except junk yard) and cant find one. Any leads as to where i can get one?