Hi,
Part of why I wanted this 84 F250 is because I want to do as many repairs as possible myself to educate myself. I am mechanically skilled, but I haven't ever done any serious auto mechanical work. My intake manifold gasket needed to be replaced on my 302, so I am trying to do it myself. I hope I didn't make a big mistake. I am following the shop manual with a Chilton on the side that seems to be just cribbed from the shop manual, but both make a lot of assumptions and could use more pictures.
Anyway, I have most everything out of the way and have most of the bolts pulled, but I have left the carb in place as instructed. I cant get to the bolt under what I think is the choke control on the passenger side of the engine. I am thinking about pulling the carb off because I think the fuel smell I am getting is from a gasket there, but I'm not positive. It would let me get to the last two bolts easily. What do you think? should I pull the carb? I also am worried about unhooking too many of the small vacuum lines that are everywhere. I did take pictures as I went along.
The engine was replaced once before, and I'm not positive everything was correctly replaced. For example, when I removed the distributor I found that the wiring harness connector had been half snapped off, and the wires are corroded.
Also, I am replacing the plugs, wires, coil, cap and rotor as part of this. Anything else I should consider? Thanks. Sorry for the long post. I'm trying to thaw my fingers.
Dan

 

Go ahead and pull the carb. The more you take off, the lighter it is to pull out. Plus like you mentioned, just going through everything you can find problems like cracked hoses and stuff not hooked up correctly/burnt out gaskets.

You can get a sharpie and some masking tape and mark the lines with something you can remember. If nothing else, mark them 1, 2, 3, 4, ,5 ...etc. Then you can count backwards and not forget to put any lines back on.

One good thing about the Ford 302, you can sneak the intake up and around the distributor, so you don't have to take that off and worry about the timing. You might have to pull one of the valve covers though. Sometimes the edge hangs over and keeps the intake from coming up.

 

Thanks. It figures one of the first things I did was pull the distributor. I took pictures aND tried to mark it, but I'm sure I'll learn that the hard way.

 

Okay,
I finally got the manifold off, and cleaned up. I bought a felpro gasket set that came with cork seals for the front and rear. I suppose I should use those in place of the RTV that was there before. Also, when I removed the carb I also removed a unit that was mounted under what I think is the choke, on the passenger side of the manifold. It is vacuum actuated, and has a small door under it inside the manifold. Should that gate open and close freely with the unit uninstalled? I didn't want to force anything, but now is the time if it needs replacing. I have to order the carb gaskets anyway, and I forgot to get new washers for the manifold bolts, so I need those as well. I'll try to add a picture.



What is this unit under the choke?

 

The unit under the choke is a door that controls exhaust flow under the carb.

There is a exhaust port in the center of each head on each side, and there is matching holes in the intake. Exhaust flows from one side to the other. This creates a hot spot under the carb, keeping the fuel atomized making the engine run better.

All the different manufacturers had these ports on their v8's, and they used various ways to control the flow of the exhaust. The most common way was to have a flapper valve in the exit of the exhaust manifold were it goes into the y-pipe of the exhaust. When the engine was cold, this flapper would "clog" the exhaust flow in that side of the engine, forcing it to back up and go through under the carb to the other side of the engine and exit out that exhaust pipe. When the engine warmed up, this flapper door in the exhaust would open. It is commonly known as a "heat riser valve". In the early days it was controlled by a bimetallic spring on the valve itself and later they added a vacuum diaphragm and a vacuum line to control it.

Sometime later Ford started using the door in the intake like yours. I am not so familiar with that unit. I am not sure if it's used in conjunction with a heat riser valve, or alone by itself. Maybe someone else knows how it worked, or maybe you can look and see if you have the heat riser in one of the exhaust pipes.

I do know it needs to move. If this system is not working, your engine can become cold natured in the winter, or it can overheat the carb in the summer and boil the fuel. When this system doesn't work or I am building a engine with some aftermarket parts, I usually tie open the heat riser, open the little door in the intake permanently, put restrictors in each side of the intake ports, and then make sure I use the heat duct on the original air cleaner. I seem to get by ok like that.

Since you have the intake off, look underneath on the bottom. You should have a sheetmetal cover on there. This cover keeps oil from hitting the hot spot under the carb and turning to carbon. Over time, the oil will get under the shield and build up anyway. You should take a small chisel and get beside the rivets and try to work them out, take the shield off, and clean all the hard carbon stuff out.

 

Thanks for the quick reply. I will clean out that pan. I do have a heat riser valve in the exhaust manifold, but it is dangling because the bolt rusted off. It's on the list. I wonder if I should replace this door unit while I am in here. I'll look at rock auto and see if I can find one.

 

If you find it, see what it's called. I would like to learn more about it. See if it's on the vacuum diagram on your radiator support. If you can find it, see if you can figure out the abbreviation for it.

 

Well, the part number stamped on the vacuum part of the gate is E3TF-9G464-F1C. Neither Google nor rock auto understood it. I can't get the picture up right now, but I will soon.

 

That is the Engineering ID number, the part number is:

E3TZ-9G464-A VALVE ASSY. (INTAKE MANIFOLD HEAT CONTROL).
Used with gasket 9E486
Fits 1983/87 Trucks, vans and Broncos w/8 cyl 302 engine; 1984/87 trucks, vans, Broncos with 8 cyl 351W enging and 4/B carb

No Ford dealers nor NOS vendors have any, methinks your best bet is going to be making your existing units usable again (if possible).

Source: FoMoco 1980/89 Light Truck Master Parts Catalog, available for ~$22 from hipoparts.com

 

Thanks for that info. Frankly, I'm not even sure if the part is defective. I just can't operate the door with it removed, and I don't know how much force it should take, or if it only operates when hot. I assume it is operated by vacuum, and that I should be able to work it. I'll try soaking it for a day in something.

 

That's what I don't know, is how it works. I don't know if it works directly with the heat riser valve, or has some sort of delay or it's own control. The regular heat risers had a vacuum valve screwed into the water jacket somewhere, and when the coolant got to about 100 degrees, they opened the valve up and let the exhaust through.

 

Attach a hand-operated vacuum pump to the nipple, apply some vacuum and see what happens. It might be stuck, the diaphragm may no longer be working, it may be fine....

 

I meant to say something about this earlier. Those ends seals have a bad habit of squeezing out when you tighten the manifold down. If the don't do it then, they do it about a year later and start leaking oil. That's why most people do not use them.

If you do want to use them, get some trim adhesive and GLUE the end gaskets to the block. You will still have to use some dabs of rtv where the end seals meet up with the side gaskets.

I just always use the thick bead of rtv. If you clean off the surfaces really good, it works well with no leaks. I think it also lets the whole intake settle down a little tighter on the side gaskets if it needs to.

You should put a very thin smear of rtv around the water ports on the side gaskets, and NONE around the ports where the fuel goes into the head.

 

Well, I have been away from here for a while, working on the truck 10 minutes at a time. I am ticked at myself for not taking enough good pictures of the carb. Now I have been running into new issues every time I work on it. I bought new mounting gaskets for the carb, and I have at least one wrong one. The shop manual goes into great detail about the carb, but less about the mounting of it. I put a thin gasket that I am confident about on the manifold. It mates up to the first block, which has what I think is the choke assembly on the back. Then I put a thick gasket between that and the phenolic block. Now I need another thin gasket between the block and the carb, but I have only a thick one on hand.
Do I have this right? Should I use any sealants here at all? Thanks,
Dan

 

The thing on the back of the spacer is the EGR valve.

Use no sealants. Fuel and sealants do not go together very well. You should be ok if the spacer aluminum is not disintegrated.