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Discussion Starter #1
I have taken the air cleaner off of my 70 Mach 1 351C-4V. I think that I am missing something or have a wrong part attached...that is where I need some assistance. The rubber hose that leads from the vacuum duct at the front of the cleaner to the bi-metal switch located at the rear bottom of the cleaner is there and attached. There is a T fitting coming out of the bi-metal switch in addition to the other fitting that the vacuum duct line is attached to. I have a rubber tube that is about 4" long that is attached to one outlet of the T fitting and goes to a metal tube that attaches to the choke heater assembly on the intake. There is nothing attached to the other part of the T. I have searched my Ford manuals, both assembly and shop manuals and can't find an exploded view of this area. I am not certain if 1) The T fitting is not correct and should just be a straight fitting like the one coming to/from the duct valve, or 2) I am missing a vacuum line that should be connected somewhere else. For those with a 351C-4V, non shaker, could you look and tell me what I need to do? Thanks!

Al
 

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Here's a vacuum diagram:
Glazier's Vacuum Diagram
I have to say I'm having a hard time following what you have. There are two taps on the bottom of the air cleaner (temp switch), one comes from the fitting on the rear of the intake manifold, the other goes to the air motor on the snorkel. Nothing goes to the front of the air cleaner from this.
If the tee fitting is between the vacuum fitting on the manifold and the temp switch, remove it. This would be used if you had a shaker, and would lead off to the vacuum motor for the shaker. There may also be a long hose coming off the vacuum fitting in the intake manifold, going forward to the multiport thermal switch on the front of the engine. It may be that the vacuum fitting on the intake manifold may have only one small fitting, and the large one to go to the vacuum tree on the firewall. If this is so, the line off the tee was probably the line going forward. My car has a fitting on the front of the intake manifold from which the vacuum is tapped for the distributor and such, so a single small port rear intake fitting, no long line.
The choke line comes from a fitting on the rear of the carb (assuming you have a stock carb, large fitting goes to the pcv valve, small fitting goes to the choke stove), goes to the choke stove, then a second steel tube to the choke itself. The steel tubes are inserted into the stove itself.
Heres a pic. Note that this is a shaker car, hence the extra tee and vacuum line:
http://mywebpages.comcast.net/cpierce64/351C 4V Lines.jpg

Carl
 

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Discussion Starter #3
Carl,

A picture is worth a thousand words...and I very much appreciate it. I still haven't figured out how to take a pic and post it here. It's dark here in AZ now, so tomorrow I'll take the vacuum drawing and your pic outside to check. I'm thinking that my stock carb may not be correct and I'll be just a bit irritated as Pony Carbs assured me that it is when I sent it in for a concours rebuild. The line connected at the carb and going to the choke heat riser does not go into the carb on mine...I don't believe there is even a connector for it. I could be wrong and will check tomorrow. Thanks for the help. I'll get this car right yet (long story!).

Al
 

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Use the paper-clip pushbutton to upload images ^^^^^
 

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Do you have a manual tranny or an auto tranny? There are minor differences to the carbs, but both should have the two vacuum fittings on the back of the carb. Carb model should be stamped on one of the mounting feet, should be D0OF-__, with the letter in the blank being AC for auto no air conditioning, AB for stick no air conditioning, AD for auto with air conditioning, and G for manny tranny and air conditioning. There were a couple of other variants listed in the books, but I haven't seen one, the date code on my AC is correct for my build date. The only downside is that the part numbers are on the base, which can be swapped from carb body to carb body.
Sorry for the pic being a shaker car, only one in my garage. :^)
Here's a pair of pics of a NOS D0OF AC (Auto Tranny, no AC) carb, from during production (not a service date code):

http://mywebpages.comcast.net/cpierce64/D0OF AC Carb Tag.jpg

http://mywebpages.comcast.net/cpierce64/D0OF AC Rear.jpg

This one has a plastic fitting for the choke line, not a brass tube pressed in, as other D0OF carbs I've seen have. Not sure what's up with that.

Carl
 

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Discussion Starter #6 (Edited)
Carl,

I compared your pics to my setup. This is an automatic WITH A/C. My carb tag is DOOF-AD so that seems correct. The vacuum fitting on the rear of the intake has one large fitting going to my firewall tree and one small one that is capped. I think that small fitting should go to the air cleaner directly instead of being plugged. I do not have any brass tube pressed into the back of the carb. There is a hole where one would go. It is open on the outside and is just a cavity...not a port that leads to somewhere else. Is this where my plastic fitting should go that connects to the steel tube that leads to the choke heat riser? I noticed one of your pics has a similar plastic fitting on the carb...perhaps that is what mine is as well. That fitting is not just a "union", but a T (see pic). Should that open end be plugged?

So, here is what I am thinking I should do. I take the plastic fitting off of the air cleaner and in its place put a line from the vacuum fitting on the rear of the intake to the air cleaner (what is the proper tubing for this?). I then take the plastic fitting and put it into the rear of the carb and connect that line to the choke heat riser. Open end of fitting needs???

Thoughts? Comments?

Thanks, Carl! And thanks 22GT for the assist on the pics.

Al

http://forums.vintage-mustang.com/attachment.php?attachmentid=15088&stc=1&d=1297874767
 

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The steel tube/nut is actually going to the choke itself.
I always assumed that the tube on the back of the carb was a vacuum source, but thinking about it, it would pull cold air through the choke, not push hot air to the choke. Hmm, maybe they just wanted to provide a path for heated air to both the carb and the choke? Different, but it makes sense.
Do you have the steel choke tube set that goes from the stove to the choke, and from the stove to the rubber hose to the carb? Knowing that the tube on the back of the carb isn't a vacuum source, probably not as needed as I originally thought.
On the vacuum side, small port on the fitting to the temp switch on the bottom of the air cleaner is correct. Second port on the temp switch to the air motor on the snorkle. That would mean taking the cap off the fitting, and putting the rubber hose onto that port.
Most of the original D0OF carbs I've seem have a metal tube in the small hole in the back of the carb, that NOS one is the only one I've seen the plastic fitting on. I'll see if I have an AD in the basement I can shoot a pic of.
And that plastic fitting sure looks like what's on the NOS carb, that makes two that I've now seen. Is it a tee, or is the part that would plug into the carb blocked? Either way, I'd put that back in the carb, and just use a straight line from the fitting to the temp switch.
Carl
 

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Discussion Starter #8
Yes, the steel choke tube set is there as you described. I have removed the cap from the vacuum fitting and replaced it with tubing that goes directly to the temp switch. I put the plastic fitting into the back of the carb...it was a tight fit but went. I then connected the plastic fitting to the rubber hose that connects to the steel tube for the choke heat riser. The other side of that plastic fitting is open. As you pointed out, it shouldn't be a problem as it is only heat that is being transferred here. But I have to wonder how long that plastic fitting will last as I believe a brass tube would be much better suited for this.

Al
 

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I've gotta agree with you. If it was a hot air port, plastic wouldn't be a good solution, it doesn't heat cycle well. Maybe why they all have brass tubes now? :^)

Carl
 

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that T dont belong there. someone must have used it for a vac guage hook up or some BS.

theres a vac tree on the fire wall.or you can use the tree on the intake. either or will work.

one hose from there should run to the inside of the Bi metal switch, another hose from the oustside to the vac motor
 

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Discussion Starter #11
Thanks, Blues Power. I made the corrections and plan on taking some vacuum readings this weekend for a baseline. Carl also gave me a lead on where to buy the correct tubing. Gosh, I love this site!

Al
 
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