Oil pressure sending unit
 

Anybody know where I can get a oil pressure sending unit for a 1952 F1 239 engine in a 12 volt. I just got the old truck rewired for a 12 volt system using an ez wire kit and every gauge works except for the oil gauge. I checked out the wire and it is hooked up right to the unit. I think I have a bad sending unit that needs to be replaced. Truck runs great now except I need to know how much oil pressure I'm getting. Wiring system worked out great. Thanks for all the information that everyone has given me over these last few days on wiring.

dennis carpenter i believe . or maybe npd . i'm purchasing the dc one at 40 bucks for the rewire on my 53 and it's been converted to 12 volt . want to run my oil filter i have for it and as such have to go back to the electronic gauge i'm told as the pump doesnt put out enough pressure to feed my gauge and the filter .................:eek:

I'm not quite sure why your gas and temp gauges would be working if you didn't put reducers on them. The gauges are matched to the senders at 6 volts. That's what you will need to do with the oil pressure gauge - use the 6 volt sender and put a reducer on the back of the gauge. Unless your rewire kit contained some sort of adapters for the gauges, you'll need to reduce all three - gas oli, and temp. Amps will work unadapted.

Like Julie said you need to install volt drops, like in my picture. I re-used all the sending unit from my old flathead on my new one and everything is working.

https://www.ford-trucks.com/user_gal...221571.520.390

I am in the same position. Don't you need a 6V oil pressure sending unit to work with the gauges? Once the voltage is dropped, then there is an isolated 6V circuit for each gauge....right? Steve

Ok, take a look at the back of my gauges I'm using two volt drops for the three. Just set yours up just like mine. The sending unit doesn't care what volts are running thru it the gauges do.

That's a good question and I have the answer. You have to provide stepped down voltage to each gauge. Whether you do that with individual reducers or a single unit is kind of a matter of choice.

Remember, power runs to the gauge first, then is grounded using a variable resistance by/through the sending unit. And Marty is correct in that the sender doesn't care waht voltage you use, but it does vary the resistance of the voltage going back to ground and thus the gauge indication. 6 Votl gauges must have 6 volt power to function correctly and they must be attached to the sending unit designed for the gauge.

Normally, the voltage reducers designed for the gauge will handle only enough amps to reduce one gauge - that's what I use because the voltage variation is less with single units. On Marty's he found some that will reduce two gauges.

Here is a picture of the single gauge reducers I used (but I only reduced the fuel gauge - the other two I converted to mechanical and glued stock faces on):

Attachment 22874

If you were to find a "Vol-ta-drop" or one of the other little units designed to reduce more amps, it would do all three gauges. And I believe some of the resto parts houses (LMC, Carpenter) have a single unit that will do all three.

Here's a picture of one on a set of gauges I have. It's the little cube to the right:


Attachment 22875

And this is a Vol-ta-drop. They don't make these anymore and they are getting very hard to find. Note that even if you hook the two output posts in series, you can still only run 12 amps off of it. Ok for gauges or one appliance (heater) but that's all:

Attachment 22877


You can take power and step it down anywhere on your truck (the ballast resistor in the ignition circuit also does this) and it flows back to ground.

The caution is two fold: First voltage reducers vary the voltage they produce based on flow (amperage) fluctuations; and second, they MUST be respected for the amount of amps they are rated to reduce. With gauges that isn't normally a problem because gauges are a low draw item. But if you want to stick a heater motor, wipers, gauges, maybe an overdrive on a single reducer, your going to overload it. And when that happens, they get hot and start a fire.

Safe when used correctly.

I have the same gauge as what is in the pic that Julies sent and didn't use any redusers except for the one that is on the right of the pic. Like I said everything works except for the oil sending pressure switch. That is why I thought it might be the sending unit it's self that is bad. There is oil in the sending unit when I take it off and turn the hole down it drips oil out so I know oil is getting to it but know register on the gauge. Are you saying that I have to put another voltage drop on the gauge it's self to make it work. The wire off the sending unit test out to be 6 volt already. Any more ideas that might work?

Ok so what yo are saying is you have one of those little cube reducers already! Super. Then chances are the sending unit is bad.

But don't buy a 12 volt sender, you need an original 6 volt sender because the reducer is supplying 6 volt power to the gauge (then to the sender to ground)

Julie, I know that I should convert all of the stock gauges to modern gauges, but I have this compulsive personality. Therefore, my next question.....I have not been able to find a 6V sending unit for oil pressure and was wondering if anyone can put me on the right track to purchase one? Sounds like Lbrauer needs one too. Thanks, Steve

you might try joblot automotive in queens, ny. in the meantime, if your running engine, put on a mechanical unit for peace of mind.

C& G has them.

P/N 41A-9278-OR $40.

https://secure435.hostgator.com/~dlv...g=79&t=597&tn=

Here is their site link with Phone # or online order.

https://secure435.hostgator.com/~dlvry40/index.htm

Also, I'm not a big fan of electric critical gauges - I like mechanical gauges. I have a gallery that will show you how to install a $15 Sunpro mechanical oil pressure or temp gauge in your original gauge case and use the stock face - looks just like original.

Here's a pic of mine all converted:

Attachment 22918

Note the temperature gauge parked on "Cold." On the stock electric gauge, it would be parked on "H"

yes I have one of those little cubes on the gauge already that all the power is hooked up to. It reduces from 12 volt to 6 volt and all is fine except for oil sending unit so I will buy one of those and see if it makes any difference. Thank for all the fedback on this problem as always you people are a great help.

Well if it isn't too late, as in you have already gone to get a new sending unit, you can test the guage, power supply and wiring quite simply....... disconnect the wire from the sending unit and hang it in the air touching nothing....guage should be all the way one way...... now momentarily touch the sending unit wire to ground, really helps to have someone watch the guage unless you are really fast on your feet :-D ..... the guage should swing the other way..... if it doesn't you have other problems....... not saying the unit is not bad just a quick check to make sure you are on the right path :)
Also, make sure the threads on the sending unit are clean as they provide the ground path for the indication circuit. If you have a meter to read resistance you can even check from the sending unit post to ground, should read some resistance other than infinity or "open"...... my two cents for the day :-blah

Thanks for the information Sparky I will try this. All though we did check to see it their was power going to the unit it's self and there was. I did not check the to see if the gauge moved the way you explained yet. So I will do this first.