(OIL AND COOLING) water temp and oil press gauges question
 

Hi,
I bought some new gauges and was wondering where to hook up the senders to?

They are electrical gauges. The oil pressure gauge came with a sender that I think will fit in the stock location. On that one, can I splice the stock gauge to that new sender so I can have both oil gauges working? Or not?

Same for the water temp one, but now I have a temp sensor tapped under the thermostat housing for the electric fan. Can't I just splice into that for my gauge?

The current sensors you have most likey do not match the gauges input ohm range. For oil pressure, tap the banjo bolt at the bottom of the rear housing, or get the ReSpeed oil pedistal mount. The temp sender should go where you have already tapped the e-fan.

i just removed the pressure sensor and put aftermarket one in place. i used the hole on the water pump housing for the atermarket stuff. dont really know about splicing though.

Hmm? I have an npt fitting on my oil pedestal that feeds the s/c. Maybe I could find something to tee the sender.

If I use that location where the efan sender is at, then what to do with the e fan one? I guess I will have to look for another location for the e fan one.

jjlrx7, the thing is that I want my stock gauges to work also. trochoid said the ohm readings will not be the same so that throws "splicing" out of the picture.

https://www.rx7club.com/attachment.p...chmentid=40252

Yeah, the tee will work. My temp sensor, bought at the local auto supply, looks like a metal thermometer that mounts on the back side of the radiator. It has a potentiometer to adjust the on temp.

https://www.rx7club.com/attachment.p...d=178766&stc=1

Cool, I will try the tee on the oil press.

Look at these pics:
http://img.photobucket.com/albums/v3...K/MVC-035F.jpg

My old cover (the black one) you can see the e fan sensor. I tapped that into the s4 housing right above that pipe that's sticking out.

Now:
http://img.photobucket.com/albums/v3...K/MVC-034F.jpg
see that pipe that's sticking out? I have it plugged. Can I use that for the e fan sensor?

aftermarket oil sender and stock sender you would have to get a metal t fitting tap it in the back plate then tap the two on top of the t...

or just have the aftermarket gauge sender taped in the old mushroom heres what i did

https://www.rx7club.com/1st-generation-specific-1979-1985-18/my-atempt-aftermarket-oil-pressure-gauge-539849/

Yeah I saw that post when I searched. Yes I did search LOL.
I like that idea, but I would like to keep the stock one working also.

But check this out, the money shot:
http://img.photobucket.com/albums/v3...inished026.jpg

No, not the money. The pic of the sender. It has two wiring posts. I just noticed that one is for the gauge and one I guess can be used for the stock gauge. It has an adjustable screw inside where that black grommet is. I guess I can hook both of them up if I could find the values for the stock one. Or is that for something else? I've never hooked one up so I don't know.

The tube in the housing is above the thermostat, so the fan probably won't go on until the thermo opens.

For my water temp sender I used this on the top radiator hose. http://www.steigerperformance.com/PR...cs/sp40001.jpg

http://www.steigerperformance.com/PRODUCTS/sp40001.html

money shot... had me goin for a sec :squint:

whats your ocupation ild be lucky to have 50bucks with my budget lol

that water temp thing looks nifty
i need more money.....

is that water or oil gauge there kim?

Kim, from what I understand, almost all OEM senders are very similar as far as the resistance of the sensors over certain ranges, so you may find that the stock guage works with the new sender.

Usually from what I've been told by an engineer friend that used to do custom installs of EFI systems, a sender will vary by say for example 50k ohms over it's range. If it is way out of wack, you are still in business. Grab a grip of various resistors from an electronics store, and if the sender is too high in impedance for the stock gauge, do a bit of trial and error putting resistors in parallel with the sender until you can see the needle move as temp changes.

Doing the parallel method you will lose half the travel of the stock guage in all likelihood, but you will at least have a moving needle.

If the new sender's resistance is too low, put a resistor in series until it works. Doing this you won't lose travel.

What won't work, is if the new sender varies by way less (say it only varies by 1k ohm over it's range). If that's the case you're going to have to use 2 senders. If it varies by more, say 200k or so, that's great, you'll have more resolution on the stock guage, but you will have to play with resistor values.

That's the oil sender blwfly. Yeah that water temp thing is cool. That would solve my e fan dilema. Thanks for the link RacerX7fb!

Hmm? I guess now with all the water temp options, I guess I will research the easiest and most cost effective way to do it. trochoid's set up looks the easiest at this point with replacing my current e-fan sensor with the probe. My main concern is it has to be clean and work right. I don't want a wiring mess.

That's good info! I love learning this stuff. So basically the sender is grounded. When the sender gets pressure, it's signal to the gauge is by ohms, so playing with resistors might get me to use both gauges with one sender unless it varies less by the example you posted. I have tons of resistors, I have a good feeling about this.

I made a similar water temp sender thing out of an old aluminum tube with an NPT fitting for the upper radiator hose in my rotary MG.

Kim, you don't want to mess around with the fitting on the oil filter pedestal. My friend and his associate locked up a couple superchargers before they started using the Atkins pedastals. These SCs were made right before Atkins took over Camden. Now with the pedastal fittings, those older units are working fine.

Like another poster said above, it would be better to install a BSP fitting into the stock oil pressure hole and Tee the stock sender on one end and the aftermarket on the other.

Or you could maybe get the RB oil pressure and temperature adaptor which fits between the pedestal and the rear plate. Just add an NPT plug to the temperature hole if you don't use it (1/4" NPT, same size as the oil return fitting you added to the front cover, which comes in the Camden kit), and your aftermarket guage to the pressure hole (1/8" NPT). http://www.racingbeat.com/resultset....rtNumber=11802 This is the one that comes with narrower studs (6mm x 1.00) and fits the short style pedestals like the kind Atkins uses in their Camden kits. In other words, if the SC sending oil line will allow, this is the correct kit to use with an SC kit. The other version (not linked) doesn't have those red plastic sleeves and uses thicker 8mm x 1.25 studs for the old tall style pedestals.

Not sure if you're looking for something to plug in the BSPT setting of the oil pedestal, but I've found two websites (one from searching within this Forum) that'll help.

Female 1/8 NPT to Male 1/8 BSP Fitting
http://www.pegasusautoracing.com/Pro...asp?RecId=3142

I purchased a magnetic plug from these guys:
http://www.magneticdrainplugs.com/ta...hread_bspt.htm

Either way, you'll be better off having a cleaner approach and less hassle.

Update:

I ended up getting the respeed pedestal and the steiger adapter.
http://img.photobucket.com/albums/v3...inished040.jpg
http://img.photobucket.com/albums/v3...inished033.jpg

They are both nice well made pieces. I'm going to work on mounting the gauges this weekend, so I will have more pics. :)