Gauge Installation Questions

Redfalken

Well-known member
I just bought a set of older Stewart Warner gauges off eBay. I got a voltmeter, oil pressure, and water temperature gauge. They are mechanical and I'm not sure how old they are but they were never used. The oil pressure is working fine but I have some questions about the others:

1) I can't get the voltmeter to work. There are 3 terminals on the back. One marked "+" on the right, one marked "-" on the left and no mark on the one toward the bottom. So I tried the obvious by hooking up some wires and touching them to the battery posts. Nothing. Then I thought maybe the middle terminal opreated some type of relay so I touched it to the positive. Still nothing. I don't think the middle terminal has anything to do with illumination because there is a hole for a bulb and socket to fit in. Any advice? It could be toast I suppose.

2) The water temp gauge works (I put it in hot water with a thermometer and it was pretty close) but where can I install the probe? I have a `70 200. There's a plug on the thermostat housing but it's on the radiator side of the thermostat. Also, I don't think it's large enough for the fitting. I don't think the opening where the current temp sensor goes is nearly large enough either but I haven't checked.

3) Does the line coming out of the back of the water temp gauge come off so I can get it through the firewall or do I need a hole big enough to get the entire fitting with the probe through? There's a thin nut where the line attaches and I loosened it but the line didn't come off. I didn't want to pull too hard. The line is very stiff.

I can post photos tomorrow if that helps. Is there anyone familiar with Stewart Warner gauges who can date them? They have "Assembled in Mexico" on the labels along with model numbers and some specs.

Any help is appreciated. Also, I have 2 sockets to illuminate the gauges but need a third. The hole is about 5/8" diameter. Anyone have a spare? I've already tried a couple of parts stores and Radio Shack but no luck.

Thanks in advance for any help.
 
re. water temp gauge--Usually mechanical water temp gauges absolutely cannot have the sensor tube removed from the gauge. On the last couple I've put in it said "absolutely DO NOT attempt to remove sensor tube". The hole in your water jacket where your stock sending unit is should be on the drivers side rear, kind of inline and well above the clutch pivot arm mount. The sensor usually screws into a brass bushing/reducer. Feed the sensor from the cab to the engine compartment Somewhere there will be a large enough hole disguised by the rubber grommet that has things like choke cables or wireing harhesses in it. Remove, pass gauge tube through fire wall- adapt tube to grommet and reinstall grommet.
The voltmeter is an even simpler thing but impossible for me to figure out without actually seeing it and exploreing with a VOM.
 
Here's a voltmeter drawing from the SW catalog.

swelec5.gif


SW also has bushing and adapters that will allow you to use the large sender in a small hole.
 
I am in the process of installing some new guages on a rebuilt 200 and have a comment and a question. I am thinking of installing the water temp probe into a 3/4" pipe tee connected to the 1/2" pipe (for heater hose) that comes out of the engine block just behind the thermostat housing! I would then reduce (bushing) back down to 1/2" pipe for the heater hose to hook-up to on the downstream side of the 3/4" pipe tee. This way I am getting the temperature from the engine block before the thermostat. Does this make sense? Does anyone see a problem with this set-up? Also I have a question concerning the installation of an oil pressure gauge. My 200 engine is in an older econoline (64') and unlike the distance that most of you have in your Mustangs, etc., where you go through the firewall to install your gauges, I have a longer run! The plastic line that came with the oil pressure gauge is not long enough for this added length (run). I have been kicking around the idea of running some type of metal line (brake line, etc.) most of the length to the dash and then hooking up the plastic line. My question is whether or not I would get a true pressure reading by running a line (both metal & plastic) nearly 6 feet or so? Would there be much of a pressure drop, if any, by doing it this way? Does anyone have any thoughts on a pressure drop or any other pitfalls by doing it this way? Thanks for any comments!
 
For the oil pressure line - if you cannot get an autometer etc "isolator" line that is long enough, then a steel tube of several magnitudes oversize would be best. You'd want to brace it well against vibration and work hardening.

As regards the temp sensor - I have seen a Ford OEM install in that position. Early 1971 Aussie made Falcon.

Cheers, Adam.
 
I saw that wiring diagram doing a search and the "+" and "-" terminals are in different positions on mine. I even tried the positions on the diagram and still no luck. The bezel is crimped around the cup so there's no way to take my voltmeter apart and there's a smaller cup inside that is riveted on so it doesn't seem very servicable. I think I'll just have to get another.

Danwagon...I have a multi-tester. Is there anything I can do to diagnose it with just the three terminals accessable?

James...good idea for installing the temp sensor. Is the pipe for heater hose a pipe nipple that's threaded into the block? I never really noticed if it was or not.

Thanks to everyone for the advice.
 
how did your rearend swap come out are you pleased with it. i put a set of new gauges in my falcon came out real nice i took the old cluster out and replaced all of them, kind of agervating but it was worth it in the end.let us know on your rearend swap im putting the same tranny rearend combo in my falcon. thanx cocacolaman
 
Redfalken, there is a fairly short (3 1/2" - 4") long pipe nipple that was threaded on one end and screws into the engine block (behind thermostat housing); and smooth on the other end for the heater hose to slide onto! I am planning on replacing this nipple with one that is threaded on both ends, then using a 1/2'" to 3/4" bushing into a 3/4" pipe "tee", and then another 1/2" to 3/4" bushing coming out of one of the other two openings in the pipe tee with a pipe nipple coming out for the heater hose. I will then install the water temp probe (for gauge) into the third opening of the 3/4" tee! I have the parts and have assembled everything and it seems like it should work!? I was just curious if anyone else had done something similar and whether anyone can see any potential problems doing it this way? I saw a post (and picture) not too long ago where someone had cut their top radiator hose and installed what looked like a p.v.c. (plastic) tee the size of the radiator hose and then reduced down to accomodate the sensor (probe). It looked real nice, but I wonder if having the temp probe downstream of the thermostat makes any difference?? Any comments from anyone on this matter? Just curious! Thanks for the feedback! I really like this website; it is just full of info!
 
If you were into electronics, you could jam in thermocouples everywhere and run a digital temp readout that cycled automatically through all locations. A simplified version might be back of head, and radiator bottom tank - the highest and lowest temps you'll usually find.
 
the one other resource I use that is a wealth of knowledge on old stuff is the H.A.M.B. at jalopyjournal.com. Ask about the voltmeter there (after posting an intro if you're not already a member) and see what they might know.
 
Would there be much of a pressure drop, if any
Actually if you manage to purge all air from the line there is no pressure drop over the distance as you cannot compress a liquid. This is why pumps can push water great distances while being able to draw only short distances. Even with air -you only lose 5# pressure in a 100' in a 3/8" line at 100PSI starting pressure. My well pump is 500' from my house and pressure at the pump and at the house are EXACTLY the same The only way to change pressure is to change volume(pipe diameter).
Although for ease of installation i used to mount oil press gauges on the front of the engine box on those old sinbins.
 
Follow-up:

I finally just bought a new Stewart Warner voltmeter after giving up on getting the other one to work. I also got the mechanical water temp gauge hooked up. I bought a 3" nipple and screwed it in where the heater hose fitting was on top of the water pump. I then added a "T" fitting on that and a new nipple for the heater hose pointing to the right side. I bought a new Stewart Warner adapter that had a 3/8" NPT thread and put it in the last opening. Painted it black so it wouldn't stick out like a sore thumb. Works great and doesn't look too clunky.

It puts the temp probe right in the middle of the stream going to the heater core. Maybe this isn't the hottest point (??) but I'll be interested to see how the gauge reacts to different situations.

h20probe.jpg
 
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