What is this thing on my Water Pump?

Platonic Solid

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What is this thing on my 73 351C 2V water pump?

351C-WATERPUMP.JPG
 
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Platonic Solid

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That's what I thought, but I can't find it on the shop manual CD (which I'm returning to Mustangs Unlimited due to the crappy low resolution scanned images). Plus, I'm guessing it's broken.
 

2+2GT

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It's a smashed distributor vacuum control valve. It's purpose was to speed up the idle to cool the engine if the coolant got to 220°. Many people bypassed or removed them under the mistaken belief they were "pollution equipment mandated by the government to rob the engine of power". I can refer you to Ford vacuum diagrams to re-install this handy system if you like.

dvcv.jpe
 

Platonic Solid

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It's a smashed distributor vacuum control valve. It's purpose was to speed up the idle to cool the engine if the coolant got to 220°. Many people bypassed or removed them under the mistaken belief they were "pollution equipment mandated by the government to rob the engine of power". I can refer you to Ford vacuum diagrams to re-install this handy system if you like.

dvcv.jpe

Well that looks remarkably similar to this (picture below), which I desperately want to get rid of as it sits awkwardly on top of the alternator (currently removed).

351C-VACCTRL.JPG


Yes, please. If you have a convenient hose routing diagram I would very much appreciate it. It's amazing how limited the shop manual is for this kind of info.
 
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bnickel

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it's actually called a ported vacuum switch and it's true purpose is to control the ignition timing during warm-up thereby reducing emissions on cold starts. it may also function to change the timing, and therefore the idle speed, when the engine gets hot in traffic but that is NOT what it was designed for.
 

bnickel

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well, actually i may not be totally correct on this one as i found the info below that backs up 2+2GT, however i know have seen other info that states what i said as well. anyway, here is the info i found


This little device may not appear to be all that important, but it has a big job to do when your engine gets too hot. The threaded end looks a bit like an engine temperature sensor, and that's because it is. It's normally mounted on the intake manifold or engine block where it can sense coolant temperature.

The three ports at the other end are for vacuum connections. One goes to manifold vacuum, another to carburetor vacuum, and the third goes to the vacuum advance on the distributor. At normal engine temperatures, the distributor gets ported vacuum, which is 0 psi at idle. During extended idling on a hot day in bumper to bumper traffic, the engine temperature can start to rise pretty fast, especially with air conditioning on. That's when this little device goes to work. When engine temperatures reach about 225 degrees, this switch changes the distributor vacuum advance source from ported to manifold vacuum, which is high at idle. This advances the timing and engine rpm increases.

The result is increased radiator fan speed and coolant flow through the engine and radiator, which tends to bring the temperature down. Once the sensor determines the coolant temperatures have dropped to a safe level, it reverts back to ported vacuum and the engine timing returns to normal, returning the idle rpm to its normal setting.

Chances are most people have never even noticed when this device is protecting their engine, they just notice that the temperature gauge drops a bit, or the HOT light on the instrument panel extinguishes.
 

2+2GT

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well, actually i may not be totally correct on this one as i found the info below that backs up 2+2GT, however i know have seen other info that states what i said as well. anyway, here is the info i found

Thanks, you saved me from transcribing the the description from the Factory Service Manual. :D

Handy little gadget to have on a 351C. They were not exactly known for staying cool in traffic.

There was a ton of other items on the 73 351 that are very difficult to find today. If you don't have them, 71 or 72 specs will provide the plumbing diagram you need to make this work. You can find them here:

Mustang Vacuum Diagrams, Shelby Vacuum Diagrams
 

70grande

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On my 1970 351 2V Cleveland, thats the temperature sensor. Does your temp gauge work? If it a smashed vacuum thing like stated above, the motor is gunna run like crap or your tranny (if its auto) is gunna have a really hard time shifting.
 

Platonic Solid

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That may explain why my 72 used to overheat while sitting in the inevitable 4th of July homeward bound traffic jam.

Apparently the 73 351C has two vacuum valves: a PVS Valve (not sure what that stands for, but appears to be the Distributor Vacuum Control Valve) and Temperature Controlled Vacuum Valve (appears to look like the 2 port valve in my second picture).

Thanks for the info. and plumbing link. :nice:

I don't mind saying, this is a real PIA to decipher - not knowing who's done what to this car over the past 36 years.
 

D.Hearne

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PVS = Ported Vacuum Switch. The idle speed increase does make sense. I recall the local cops where I lived in the 70's used to pop the hood latch and let some of the hot air out when idling for extended periods
 

Platonic Solid

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On my 1970 351 2V Cleveland, thats the temperature sensor. Does your temp gauge work? If it a smashed vacuum thing like stated above, the motor is gunna run like crap or your tranny (if its auto) is gunna have a really hard time shifting.
I think the temperature sensor is the device in the manifold just above and left of the red circle. This car has the factory oil/alt/temp gauge cluster in the center console. It's been so long since I've actually driven it that I can't say if any of them work. I'll check when I get it re-assembled.

The motor actually runs pretty good since rebuilding the carb, tuning it with a vacuum gauge and putting the timing at 10B - that is, as long as I plug the EGR vacuum line. I'm guessing the EGR diaphragm may have a small leak as it does open when the vacuum hose is attached - but, yes, then it runs like crap.

I have to fix the tranny leak before I can comment on any other potential causes of shifting issues.

351C-WATERPUMP.JPG
 

2+2GT

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I think the temperature sensor is the device in the manifold just above and left of the red circle.
You are correct.

The motor actually runs pretty good since rebuilding the carb, tuning it with a vacuum gauge and putting the timing at 10B - that is, as long as I plug the EGR vacuum line. I'm guessing the EGR diaphragm may have a small leak as it does open when the vacuum hose is attached - but, yes, then it runs like crap.
The EGR is available new, if you need one. It is controlled by the Temperature Controlled Vacuum Valve, also available.
tcvv.jpe


You'll want to keep the EGR operating, using this valve, but if all your other 73-unique emission controls are gone, and you want to use the DVCV (which is what Ford usually calls it, NAPA calls it a ported vacuum switch) just use one of the applicable 71 diagrams.

71%20351C%202v%20with%20dvcv.gif
 

Platonic Solid

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I'd like to setup the vacuum system as originally intended, but that may not be possible. The vacuum switches seem easy enough to find, but I haven't been able to locate the two normally open solenoid valves, the check valve, and the spark delay valve. I also assume that somewhere I should be able to locate (item 9) the "ambient temperature switch", but the shop manual doesn't seem to be much help in telling me where to look for it. I suppose that could be missing too since the solenoid valve it's supposed to connect to isn't there.

73%203-14A.jpg
 

2+2GT

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I'd like to setup the vacuum system as originally intended, but that may not be possible. The vacuum switches seem easy enough to find, but I haven't been able to locate the two normally open solenoid valves, the check valve, and the spark delay valve. I also assume that somewhere I should be able to locate (item 9) the "ambient temperature switch", but the shop manual doesn't seem to be much help in telling me where to look for it. I suppose that could be missing too since the solenoid valve it's supposed to connect to isn't there.

Well, the check valve is easy, and the spark delay valve may be available, and the ambient temperature switch is on the air cleaner base. The solenoid valves could be a problem.