Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: Benjy on Monday,June 09, 2025, 05:34:27 AM
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Ahoy All,
My ancient sender packed up and left my gauge needle pinned to the right. I looked in to buying a replacement but was shocked to discover that they are ludicrously pricey for what they are and come with a 1/8" NPT thread which means you also need an M14 x 1.5 adapter. There must be an alternative thinks I. And so I went down the Smiths instrument rabbit hole... Again!
What I discovered is that Smiths gauges (unlike most) have a range of resistance from 240 Ohms (0 on the gauge) to 33 Ohms (100 on the gauge). As well as the importance of matching the resistance it's also important to mate the range. The smith gauge on the Renault engines cars has a 0-100 psi range or 7 bar.
After much trolling of various forums I discovered that a Lada Niva has a very similar sender, the only difference is that it is for an 8 bar gauge. Close enough I figured and since it was a sixth of the price of a Smiths one, took a chance. Because the sender is an 8 bar and not a 7 bar I added a 477 ohm resistor to reduce the resistance a little to try and match the original gauge. The gauge is wired as normal but an additional wire is taken from the same point on the sender through the resistor and grounded to earth. This has the effect of raising the pressure shown on the gauge at the cost of some slight sluggishness.
So, although not as good as the original set up it does at least work and show pressure and perhaps more importantly it will also show when there is no pressure. And this sender even has the correct 14 x 1.5 thread so needs no adapter.
For those who wish to try this themselves a 477 ohm resistor has the following colours: Yellow, Violet, Black, Gold. Yellow = 4, Violet = 7, Black is a multiplier and Gold = 5% tolerance. You can fit the resistor around either way.
The part number for the Lada Niva oil pressure sender is 2103-3810300-01
Cheers
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Is this what you’re looking for?
https://www.sjsportscars.com/parts-and-accessories/X046E6378Z.htm
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That's the one. Shocking price! Which is why I wanted to find an alternative! Now that the UK is no longer in the EU it is even more expensive to buy from the UK.
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Demon Tweeks lists a pressure sender for Smiths gauges for about $60 US. It will need an adaptor to fit the Renault block. Not sure how accurate it makes things but might be worth a try.
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The Lada Niva one does need an adapter and cost $20 delivered. No contest.
I just thought others might be interested to learn that there is an alternative.
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Benjy, thanks for the info. I may need a new pressure sensor so I'm glad to know there's a better option.
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There are only a handful of gauge ranges, almost always an alternative that might not be immediately mechanical compatible.
I don't think anyone mentioned it, but there are various devices such as the Spiyda Gauge Wizard which allows you to use basically any resistance based sender and map it to the gauge. https://spiyda.com/fuel-gauge-wizard-mk3.html (https://spiyda.com/fuel-gauge-wizard-mk3.html)
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That's interesting. It makes no mention of oil pressure gauges, do you think this would work?
Still quite a pricey option for those not in the UK though.
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Definitely, I've used those and worse Chinese ones for temp, fuel, pressure, really anything with a resistance-based output. Even an overdrive pressure gauge once.