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1256 Oil Gauge Wiring / sender

PostPosted: Thu Jul 13, 2017 5:23 pm
by rattlyolddt
I have acquired a trio of worry gauges.

Volts is easy, and i may swap temperature for a rev counter, as I have a temp guage on the dash.

However I am stuck on the oil. - It's an electrical one, not mechanical/plumbed in.

I assume the current oil sender is a switch, for the oil pressure light.

I'd quite like to keep the oil light too, but understand I'll need a sender for a gauge, not a switch.

How have folk got their gauges wired up ?

Cheers

Ed

Re: 1256 Oil Gauge Wiring / sender

PostPosted: Thu Jul 13, 2017 6:41 pm
by droopsnoot
It would need to be a separate sender, as you said the pressure switch you already have just connects the spade terminal to ground when the pressure drops below a certain figure (often 3-4psi), so isn't any use for a pressure gauge.

On OHC, those cars that have a pressure gauge have a second fitting - the larger fitting screws into the block where the pressure switch did, and the pressure switch then screws into that fitting, thus keeping both indicators. So you could probably do something similar on the OHV engine, if you can find the correct bits. A lot of these senders are standard fitment, though, so it might not be too difficult.

People like Rally Design, Merlin Motorsport, Car Builder Solutions, Demon Tweeks and many more are the kind of place to look for sender units and adapters.

ETA - ignore the throttle cable, the picture shows the standard pressure switch (A) as it piggy-backs on to the oil pressure adapter (B). So you'd probably need something similar, but with two threaded holes rather than the hole for the oil pipe on the top of this one.


Re: 1256 Oil Gauge Wiring / sender

PostPosted: Thu Jul 13, 2017 7:11 pm
by rattlyolddt
Cheers Mike

The sender with space for the original switch would be a neat easy solution.

Do I need to worry about the correct resistance in the oil sender for the guage?

Re: 1256 Oil Gauge Wiring / sender

PostPosted: Thu Jul 13, 2017 8:08 pm
by 1972nail
The Mini has dual switch and guage fitting just like the OHC and it will fit an OHV engine. The Mazda MX5 MK2 has an electrical oil pressure guage but it isn't really any use as it only switched to show normal pressure when the light goes out.

Re: 1256 Oil Gauge Wiring / sender

PostPosted: Fri Jul 14, 2017 11:16 am
by droopsnoot
rattlyolddt wrote:Do I need to worry about the correct resistance in the oil sender for the guage?


I'd imagine they would have to match. I guess they work by variable resistance between zero and something else, so it will be down to determining how a perceived voltage at the gauge of say 6v relates to a specific PSI. But I'm not up on these things, maybe they're all the same. The catalogue I looked in didn't talk about different ratings.