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I have a friend (who I will invite to here) wanting to reinstall a 460 into an F250 - something like that, anyway.
And he's asking me some questions, and I forget the correct answers on what looks to be part of the hot fuel handling package with electric pumps... he's asking what this is:
I recognize that thing from the parts catalog + previous discussions out here, the 9N176 and/or 9C400 stuff as being part of the fuel return line system:
He's also asking about the AIR injection tubes into the backs of the heads, there's a PDF of his attached... IIRC because of the visual test (which he needs to pass) I would leave the tubes in place, at least set up so they appear to be functional... he'll want the AIR pumps + EGR valve, too, but it doesn't need to be operational, just present and appear to be functional.
His exact questions are:
The parts I currently have questions on are these two parts. The first is the fuel part you described as part of the hot fuel system, is it necessary to replace it exactly with the same part (hard to find and expensive) or can I use a regular “T”?
Second is a pipe that runs from each head up to a junction point, is this emissions? Can I eliminate them and block it off?
Does anybody here remember this stuff off the tops of their heads? I looked into the parts catalog a bit and was greeted with calibration code lookup tables, ugh....
Here are some pictures and a PDF showing the AIR tube stuff:
My truck is a 1987 F250 Custom,
460 carb, 4spd, extened cab, long bed. In the tank electric pump, no mechanical pump.
It's not FI, (I believe it was last year of 460 carb, I also think they had fuel injection during that year)
I've had a lot of problems getting parts because 86 87 88 were big years for changing a lot of things!!
Just a WAG, it looks like a filter but with two lines to it I'd wager it's a regulator, line out the side is return. Put air through it and see what it does?
I'd leave it off and just use a normal mechanical pump.
I'm the friend and owner of the 1987 Ford F250 460. I'm putting my rebuilt 460 back into the truck and I need to have the emissions equipment in place, view able for inspection. In NC the inspection for my truck is safety inspection only. But its supposed to have the emissions equip that came with it, technically it does not need to work. I need to pass the Inspection but I want the least amount of that crap on my truck. If I have to I'll put it on for inspection. The next big thing I worry about is the vacuum lines. Any ideas on navigating this process would be extremely helpful. Thanks.
I had a 1973 Olds 455 that had a three-port mechanical fuel pump. The 3rd port was a return to the tank, it took a regular size fuel line, but the port had an orifice to limit the amount of fuel that was bypassed back to the tank. The idea was that by allowing some fuel to constantly cycle back to the tank, it kept the fuel pump (and fuel) cool. It worked great, it never vapor locked in the worst of conditions, something I couldn't say for some other V8s I had.
The Ford part under discussion here seems to be an in-line equivalent, but must have a valving function, I assume a spring is the pressure sensor, that opens the return (3rd port) through the orifice when... pressure drops because of vapor, not liquid? or pressure high because of expanding vapor instead of liquid? Don't know which.
Anyway, if one were to try to substitute a "T" instead of this gizmo, I would choke down the return side quite a bit! One could even do that by crushing an attached steel fuel line to allow only a small cross-section flow in the return direction.
The first item is the vapor separator from the Hot Fuel Handling system.
There is a filter screen in there and a calibrated return orifice.(basically a jet)
They were 0.040=blue, 0.060=red, and 0.090=white.
Subford has the P/N's in his reply (post 126) to Gary's Hot Fuel wiring questions in "Big Blue"
As for the thermactor crossover pipe at the back of the heads, what is the question?
Does he need a new one?
There is one A.I.R. pump for that pipe and one A.I.R. pump for the 'spider' log manifolds attached to the valve covers.
My '87 has a mechanical fuel pump but some photos can be found in my Flickr set from when I replaced the engine and joined the forum in 2008
I'm the friend and owner of the 1987 Ford F250 460. I'm putting my rebuilt 460 back into the truck and I need to have the emissions equipment in place, view able for inspection.....
The next big thing I worry about is the vacuum lines. Any ideas on navigating this process would be extremely helpful. Thanks.
There should be a vacuum line diagram on the underside of your hood.
Mine is pictured at the end of my Flickr set.
I have the 1987 EVTM.
If you need something from that lmk
As for the Thermactor & A.I.R. tube stuff, he's wanting to deactivate that stuff but leave it in place for a visual inspection, people have used various techniques to do this.
To add to what Jim said, a tee cannot be used as you will have no pressure to the carb since all to the fuel will return to the tank with no resistance. An option to replace the vapor separator, and the one I'm going to use, is to put a return style pressure regulator in place of the separator. It should be as close to the carb as possible so the fuel running on to the carb is kept cool.
If he wants to keep the air pipe there for looks, I would take and make a solid block-off gasket at the head junction, or I think some people use a little freeze plug to block it off. And then bolt the pipes back on. If you don't block it off, condensate and exhaust gases will find their way into the pipes and lay in there without the air from the pump pushing through the pipes. It's very acidic, and will rot the pipes out. So block it off to keep the exhaust out of the pipes if there is not going to be any airflow from the pump to keep them cleaned out.
It looks like NC law is for ODB emissions inspection, l assume that means if it has a computer they plug it in and if the computer on the vehicle reports good with no codes it passes. NJ recently changed to no safety inspection and emissions only for vehicles under 10k GVWR that have OBD computers to plug in... Hence, everything I own is now exempt and this is one of the few areas we are actually free in this state.
Anyhow, if that's the case you should be fine to de-smog it and enjoy significantly more HP and MPG. If you need to pass a visual that's a different story, but you can still de-smog and enjoy all the gains while maintaining appearances. That is the route I would go if a visual is required but they don't stick the tailpipe.
Regardless, this particular device in the fuel line is not emissions equipment and can be left off regardless of emissions laws. If you want to upgrade and still have concerns over heat soak and vapor lock it's an easy fix with superior components. Just use some heat insulating sleeve over the fuel line from the pump, a phenolic carb spacer, and if you are using a higher output pump you can install a proper regulator as well which will keep the return system in place.
Before I got rid of the return fuel system, I would try to figure out if the original in tank pumps can be dead-headed when the carb needle shuts. Some pumps can, some pumps can't.
When it works it's not a bad system with actual benefits in very hot weather with long idle periods. There was a reason they put it on there, it's usually only on the 460 equipped vans and trucks.
Before I got rid of the return fuel system, I would try to figure out if the original in tank pumps can be dead-headed when the carb needle shuts. Some pumps can, some pumps can't.
When it works it's not a bad system with actual benefits in very hot weather with long idle periods. There was a reason they put it on there, it's usually only on the 460 equipped vans and trucks.
I don't want ro get rid of the fuel regulator/return, I'm looking to replace with original or aftermarket. Thank for the ideas.
In NC, for this years model, it is safety and visual only, no OBD this year model.
I really don't know much about the emissions equipment so I'm trying to learn, I appreciate all the info and ideas. This will be a fun, weekend and parts chaser truck. 460 and a 4spd, What's not to like?
03-24-2017, 08:11 PM
