'50 chevy 3100

[8man]

Matt, good work. Test the switch with your vom to see which prongs on the switch do what. Then test the wires you ran to the switch to see if they are power or ground. Then you will know for sure it’s hooked up right.

[Matt_50]

Got it running for a few minutes until water temp rose and dropped. Fan came on like it's supposed too and I'm very happy with how quiet it is and how much air it pulled.

Headlights work but I need to check on driver side turn signal.

Used old oil sender with new gauge. I guess it's not compatible because it maxes out. Unless there's another problem. With how close I am to firewall, I'm not sure how to reach in and change it. Is there another spot I could use for the sender?

[dsraven]

on the horn, the wire is simply "ground to operate". usually, if it worked correctly before a steering wheel or column change, then the problem is in the column. if it blows with the steering wheel off then it could be a pinched wire under the signal switch or inside the column since you say the sig switch is new. if you simply unplug the column and turn the key on and find the horn doesn't blow anymore then the problem would seem to be in the column somewhere. since the wiring to the column is unplugged at that point you could do the continuity test on the horn wire right then to see if the wire has continuity to the column or not. if it does, pull the screws on the signal switch and pull the switch out a bit, retry the continuity test. sometimes the wire gets pinched under the switch. if the problem is in the column just keep bulldogging it until you find the short to ground. if the problem is NOT in the column,
you could:
check the relay, the contacts could be welded or stuck together inside the relay or you simply have a faulty relay. use a light in place of the horns so you know the horn draw isn't gonna weld the contacts together again if there is a horn problem, plus it is less annoying to have a light come on instead of the horn blowing. make sure to test the light to ensure it works so you have trusty testing. first do the wire tests on the relay to ensure you have the circuits correct, power,load, signal. the signal wire is the one that goes to the column. leave the column connector unplugged and see if that wire has continuity to ground when disconnected from the relay. if it does then it has a short to ground somewhere between the relay and the column. pinched or stripped of insulation on a sharp edge during install or rubbed through someplace.
on the oil pressure sender, you could plug the hole on the block behind the intake manifold and use the threaded hole just above the oil filter if you have room. gauges have ohm ratings so the sender has to match the gauge. if you unplug the sender the gauge should go either all the way up or all the way down. then, if the sender wire is grounded, the gauge should go all the way in the opposite direction. a good ground to the gauge and to the engine is a must, of course, as is the correct rating of sender. also, some senders are simple on/off switches so if you have a gauge that reads pressure you will need the sender that also allows a variable ground voltage based on oil pressure instead of the simple on/off style switch.

[Matt_50]

I thought I'd check for a grounding issue on the oil sending wire. I unplugged it from the sender and no ground. Engine is still running and I look at the gauge. It is still maxed out but I noticed it doesn't jump anymore. The needle moved back and forth maybe an 1/8 of an inch before.


So I pulled my little cluster out to see if maybe something touches when it's running. There are three posts on the gauge. B, T, GROUND. Just like in this picture.

From a good ground to the sender wire, T, I do not have continuity.

Ground to ground I do.

From B, to T nothing.

From B to ground. I also have continuity. Is that right? B to the gauge case and B to a good ground or to the ground post beeps at me.

[dsraven]

unless they started building gauges differently these days I am pretty sure you need some continuity between the B and the T.
there are 2 coils inside the gauge making a magnetic field. one coil is a constant and it's field will move the needle all the way over to zero. the other coil has a varied by the amount of ground given by the sending unit. that field varies so the needle will more easily pull toward the zero mark by the stronger constant magnetic field on the other side of the needle. should the oil pressure spike then the needle would, of course, be drawn over to the high end of the gauge. it would make sense, then, that there should be some continuity between B and T. the internal coil would ground through the ground connection on the back of the gauge. since you have the gauge out you could easily test it on the bench with a battery and some test leads with alligator clips on the ends of the leads. connect batt neg to the ground, batt pos to the B and then see what the gauge does. it should spike to the zero end of the gauge. now ground the T connection with another test lead and the gauge should go to max oil pressure.
we are talking about some pretty small coils here so a continuity test may result in some pretty high ohms. sometimes best to simply test it manually with the old battery trick. you can also connect the oil pressure sensor to the air line if you have a compressor and use a pressure regulator to control the air pressure (with a gauge so you know what pressure you are feeding the sensor). the oil pressure gauge should react like normal. if it has nothing then suddenly as you increase the air pressure the oil gauge goes to full pressure you possibly have a sensor for an idiot light that is actually an on/off switch instead of a variable resistance sensor.

[Matt_50]

Ok, pulled it out and tested it on the battery.


Ground wire to ground.

B wire to positive.

Gauge then maxed out to 80.

I then added T to ground and it went to 0.

[Matt_50]

Not sure if it makes a difference but with ground wire to ground and positive taken off... I put the T wire to positive and it maxed out too.

[Matt_50]

And sincevwe are talking about the oil pressure gauge. Can someone help me verify what these three things are. The one behind distributor is my sender right? But I have a two prong thing above oil filter and I have some other thing on passenger side above pan. Has a funny plug but the single wire just hangs.

[57tailgater]

If you're talking about a SBC, the one by the distributor would be your oil pressure. The one by the filter looks like it may be for a low oil pressure warning light with the two connections. Not sure what the other one is - may be an oil temp but not sure what gets monitored at that port? Can't see the connection well enough.

[dsraven]

distributor fitting-oil pressure sender
above oil filter fitting-also oil pressure port
fitting ahead of starter-knock sensor-goes right into water jacket and pre-electronic spark timing engines simply had a block drain or a pipe plug in that spot-used on engines with electronic spark timing modules. some shops would simply remove the est distributor and install a regular distributor to eliminate the module when problems arose.

use the port by the oil filter for oil pressure gauge if that has enough room and not gonna fry the sender or wiring with exhaust heat. you can then simply leave the old sender in the top port as a plug. run the wire a bit longer and connect to the new location. lots of older vehicles, especially trucks, used that lower location for an oil pressure sender.

[Matt_50]

Thanks guys. I'll need to find an adapter or extension for the oil filter spot. Make it stick out a bit to put the sender on.

[Matt_50]

Turns out I can't get a custom braided steel brake line made here in town. Went all over town. I'll have to call around tomorrow to online places.

Did get driveshaft dropped off to be shortened. Also ordered a column shifter kit.

[Matt_50]

Got a brake line coming from Off-road Design. If I had routed the hard line differently this might have been easier, but oh well.

After some searches on the web I got a swaging tool from home depot to do the parking cable. Got lucky, 30 dollar tool. Hard to find and when the lady who was helping me did find it she knocked half price off because it was a bit scratched up. Lol I wanted was a sku number and she marked it down.

[Matt_50]

Just double checking... but to block off oil or coolant ports or adapt fittings or extend for the sender, I can just go to home depot and get brass plugs and fittings right?

[Matt_50]

Since I wanted to block off unused sensor ports and maybe move the oil sender, I thought I'd take off the extra stuff and go to home depot. While I was under the truck I was able to reach up above the trans and get a wrench on the oil sender behind the distributor.

I could only move about a 1/4 of an inch, and it took the better part of an hour to replace one sender but I got it!! Hooked up the gauge and I'm good to go.

[dsraven]

nice. forward momentum
if using a sealer on the threads use a liquid style and not teflon tape. it has a way of getting threaded off into the oil galleries.

[8man]

Nice! You'll be driving soon.

[dsraven]

does your gauge work properly now?

[Matt_50]

I think I'm taking more steps forward than back lately lol

Took back the swaging tool to home depot. Yep, popped right off. I did a bunch of searching and ordered a c10 parking brake cable that was 8 inches longer than what I originally wanted. But I'm pretty sure I can make this difference up by moving the mount spot back on the frame.

[Matt_50]

As far as I can tell. Read about 60 pounds at start up. Went down to 50 after a while.

This good?

I don't remember what the gauge read in the c10. I know it's a newer crate motor with maybe 9000 miles on it.

[Matt_50]

I was a little concerned at first but found this thread.


https://www.jalopyjournal.com/forum/...50-290.395682/

Maybe I need to run it longer than just a few minutes? I've ran it just enough to check leaks, and test electrical, and play with linkage.

[joedoh]

10 psi per 1000 rpm is the LOW limit, if you had a blockage and super high oil pressure it would have already turned into a knock or a squeal. I say run it!

[Matt_50]

Column shifter installed! Took almost 3 hours of fussing with it it and checking and double checking.

[8man]

When is that test drive?

[Matt_50]

Well, I hope to pick up the driveshaft Monday or Tuesday. The rear steel braided brake line I ordered is supposed to be here this next week, the same for the parking brake cable and rear lights.

So I'm hoping within next two weeks!