That piece on the air cleaner snorkel is your hot air system and that is the hot air valve. If you look up inside the end of the snorkel you will see a metal door. Below this metal door is another round hose connection (large hose). This hose went down to a metal shroud around the exhaust manifold called a "heat stove". When the air is cold outside, a sensor inside the aircleaner puts vacuum on that snorkel piece, and it moves the metal door and lets the engine draw air from the bottom hose that comes from the heat stove, this is warmer air and helps the engine run better when it's cold out and helps keep the carb from freezing up.

That's where the vacuum line goes on that snorkel piece, it goes around to a temp sensor mounted in the air filter housing, and then from there it runs to manifold vacuum.

The other thing you circled is your fresh air intake for the engine. As your new PCV valve sucks out the bad air from inside the engine, it needs to be replaced with clean filtered fresh air. You can see that piece has a pipe leading to the aircleaner housing where the fresh filtered air comes in and goes into the engine through that piece mounted in the valve cover.

 

Hey thanks for the info. Does either side of the fresh air intake need to be "secure"? Both ends of this intake are loose and kind of just hanging there.

Does the whole air cleaner intake assembly look right to you? The whole mounting scheme (brackets, the way parts are fitting around it) seems a little off. If anybody has an image of an original 1980 F150 engine bay, I'd like to look at it. All of my resources use newer models for their example images. I feel like a lot of things have been toyed with and I'm trying to get it as close to original as possible.

 

You probably need new grommets to tighten the PCV fresh piping. The Help! section at the parts store usually has a selection of grommets that will work.

I have never had a six, so I don't know if your aircleaner is correct or not.

 

That air filter assy. is right as far as I know and what I have on my 81 F100 300/six.

I see you have the right bracket from filter assy. to the head that I did not and had to make.
Been a bit since I played with mine but the top & bottom should have a tab so the snorkel points in the right area. The tab may be bent just bend it back and the rest should fall into place.
edit: just remembered that tab fits up into the bracket that the bracket going from head to filter assy. bolts to.

In your picture and mine you can see the hole in the filter housing that the breather filter fits into and held with a C clip.
There should also be a plastic 90* fitting on the end of that filter and is held with the same clip, I could not find that 90* fitting in the help section.
It looks like on yours the hose is just pushed inside the filter housing and would be pulling un-filter air into your motor for the PCV system.

Then a hose rated for oil/PVC runs from that 90* fitting to the valve cover.
You have a cap that the hose is connected to, mine I found a plastic 90* fitting to hook the hose to and the rubber grommet in the valve cover.

I don't have any other pictures but can get some if you need them.
Dave ----

 

I checked my air filter assembly again, and I don't have a PCV breather or retaining clip! I found these parts and also new grommets/caps on LMC, so I'll be putting an order in soon.

Next on my list is to replace the fuel filter and under-hood vacuum hoses. I also notice a loud squealing noise when reversing sometimes, usually when the steering wheel is turned all the way... So i'm also going to drain and replace the power steering fluid. While I'm at it, I might do an oil change too.

How do I know which hoses are vacuum hoses? Should I buy generic vacuum tube in a variety of sizes and replace what looks similar?

 

Vacuum hoses generally do not have clamps holding them on. Fuel lines have clamps, water lines have clamps. Your large vacuum line to the brake booster may have a clamp.

 

That is vary good way to remember it.
I will add the only ones that I see need to be made for oil/fuel is the fuel lines (tank>metal line, metal line>to fuel pump and at the filter), the PCV hose from the valve in the valve cover to intake/carb.
Also the power brake but not because of oil/fuel but that hose is stiffer and will not get sucked closed.


If the P/S belt is loose it can squeal.
Dave ----

 

Is this part (green circle) the fuel filter? It looks slightly different than the Autozone replacement part (https://www.autozone.com/filters-and...ter/830803_0_0), just wanna be sure.

 

Yes, that's a fuel filter; it looks like a generic, all-purpose variant.

 

Okay so I got a little more done this week. I decided to do an oil change. I was happy to see that the drain plug was intact, and not stripped at all. Here it is about halfway unscrewed:



I found that there was only about 3 quarts of oil in the engine... luckily I haven't been driving around since I bought it. New oil filter is blue. Maybe one day I'll paint the whole engine blue... that seems to be in style:


One of the next things I need to do is figure out what all these hoses do and how to clean them up/get rid of unnecessary ones if any.


PO capped some ends... need to determine what these are. My vacuum hose diagram has been painted over, I'll need to find one on this forum:


Finally, I replaced the fuel filter. This filter is a lot smaller, and the hoses I replaced are a little smaller as well.... I hope this doesn't have a negative impact:



One thing I noticed today is that the engine was idling pretty fast, until I pushed in the gas while in neutral. It then suddenly dropped in RPM and became quieter. So, I'm assuming I need to mess with the fast idle/idle screws soon. However, after doing all these tune-ups the engine sounds much better than when I got it. Next on my list is a coolant and power steering flush!

 

You will have to kick down the idle like that normally. You have to press the pedal to the floor before the first crank in the morning to set the choke, and to reduce the idle speed as the choke opens, you have to tap the throttle to make it idle down. It's a quirk with carbs, everyone used to know how to run them, now fuel injection has taken over all that.

 

Yeah... R5, do some homework on life with a carbureted engine, what you describe is the expected operation of the choke.

 

Okay I didn't know that! This is my first carb engine. I will look into it more. It's a little challenging to know what sounds right and what needs work.

 

I have a little issue with this picture

That rubber hose used for the fuel filter is that vacuum hose?
You need to use hose rated for fuel. If it is not it could spring a leak spraying fuel all over and could cause a fire.
Then everything is over but the crying!
Dave ----

 

Dave, those are indeed vacuum hoses... I realized this wasn't correct after I installed it unfortunately. I'll be buying fuel lines and clamps next time I go to the store to replace them. Thanks for the heads up!