KiwiTR6 Posted August 21, 2023 Report Share Posted August 21, 2023 In the recent past I did some work on my voltmeter which seemed to be worth the effort at the time, but now when I'm out driving It often indicates lower than I would expect given that I have fitted a new higher output alternator. I really don't have any confidence in it and it also frustrates me that it takes so long to react. So I've hatched a plan and purchased a cheap 52mm gauge off AliExpress that cost me roughly 8 UK Pounds delivered. I'm a bit disappointed that the interior is white and not black as it appeared in the listing, but it responds immediately to voltage change although it's a little off the real value (according to my AliExpress sourced adjustable power supply). I can see an adjuster but I'll leave that alone for the time being. My plan is to transplant the internals into my Smiths gauge, the face is very similar and wouldn't look out of place behind the Smiths front panel. Problem is, the painted metal bezel is pressed onto the plastic housing and I don't want to try and prise it off as I may end up using it if plan A doesn't work out. So, do I cut the plastic housing just back from the bezel or just forward of the rear face to remove the innards? Quote Link to post Share on other sites
BaulyCars Posted August 21, 2023 Report Share Posted August 21, 2023 I'd still be inclined to prise off the bezel - you'd be able to press the bezel back into place if you did want to use it and once mounted into the recess of the dash you shouldn't see the where you'd prised it off. Otherwise I'd probably vote for cutting it just behind the bezel (cutting into the band of 'white') - one would hope the two front screws mean the internals will come out the front (and crossing fingers that the needle pulls off ok). Readings look good! Quote Link to post Share on other sites
TR NIALL Posted August 21, 2023 Report Share Posted August 21, 2023 You don’t show a Pic of the back of the Bezel but if it was me that’s what I would be attacking,it must come off somehow. Quote Link to post Share on other sites
KiwiTR6 Posted August 21, 2023 Author Report Share Posted August 21, 2023 The casing is plastic so my fear is that trying to prise the bezel runs the risk of cracking it. It's clamped over the rim pretty well as you can see. Quote Link to post Share on other sites
Mike C Posted August 21, 2023 Report Share Posted August 21, 2023 You've tried removing all the nuts at the back of the case in the hope they may hold it together? Quote Link to post Share on other sites
TR NIALL Posted August 22, 2023 Report Share Posted August 22, 2023 7 hours ago, Mike C said: You've tried removing all the nuts at the back of the case in the hope they may hold it together? Yes that looks like the way in. Quote Link to post Share on other sites
Mk2 Chopper Posted August 22, 2023 Report Share Posted August 22, 2023 Tried twisting the bezel? Gareth Quote Link to post Share on other sites
KiwiTR6 Posted August 22, 2023 Author Report Share Posted August 22, 2023 OK, so last night I followed general consensus and prised the bezel off. Took quite a bit of effort using an o-ring removal tool slowly working my around too many times to remember. Got it off in the end but managed to break the glass in the process which surprised me as I though it would be acrylic or some type of plastic. Anyway, I'm sure I can source a replacement at minimal cost if I need one. The unit seems to be of reasonable quality, but the steel casing over the coil has the positive and negative terminals protruding through it with only a few thou of clearance preventing a short circuit! So moving on, can anyone confirm that the steel casing is an essential part of the meter mechanism? If it is, then I'll need to open the holes up a bit and insulate the positive stud at least. If not, I'll leave it off. My feeling is it has to stay as it wouldn't be there if it wasn't needed. Quote Link to post Share on other sites
RobH Posted August 22, 2023 Report Share Posted August 22, 2023 It looks like some sort of moving-iron meter. The metal can might be intended to act as a magnetic shield. It's easy enough to insulate the studs - a couple of layers of heat shrink sleeve will do it, probably without any need to open up the holes. Quote Link to post Share on other sites
KiwiTR6 Posted August 23, 2023 Author Report Share Posted August 23, 2023 Yes you're probably right Rob, I might also remove some thread down low for some extra clearance. Quote Link to post Share on other sites
KiwiTR6 Posted August 23, 2023 Author Report Share Posted August 23, 2023 Well removing the bezel was the right move as the new mechanism is too long to fit in the original Smiths casing. I enlarged the holes in the steel cover as there wasn't enough depth to use heat shrink, then superglued it in place. The lip of the new plastic housing was too large in diameter to accept the Smiths bezel so that was ground down a bit and slots made as well. It was also too thick meaning I couldn't install either of the glass support rings so the glass is now secured to the bezel with some E7000 glue. I've painted the visible portion of the housing interior with my go-to black PA10 and hope to get it all together and into the car over the next few days. I don't have photos at this stage but I tested the new gauge with a 50 Ohm (I think) resistor on the positive feed and this corrected all reading to EXACTLY match that of the adjustable power supply. I'll post details and photos of this when it's all together and before I fit it to the car. Quote Link to post Share on other sites
KiwiTR6 Posted August 24, 2023 Author Report Share Posted August 24, 2023 Final assembly completed this afternoon. The back light is an LED with its own control chip as you can see in one of the photos. I broke the head off one of the many push in bulbs I have lying around and soldered the wires to the base after cleaning it up with a small diamond file. Next I made up a couple of short connecting leads with a 10 Ohm resistor inserted into the positive one and protected/supported with heat shrink. I managed to find a couple of imperial brass pillar(?) nuts that I tapped out to 5mm to match the studs on the new gauge. This will enable me to more easily secure the bracket behind the dash. I also did another set of voltage comparisons and as you can see, the readings are very close so I'm super happy with the outcome. I'll post a photo of it in the car shortly. Quote Link to post Share on other sites
Mk2 Chopper Posted August 24, 2023 Report Share Posted August 24, 2023 Looks superb, I did the same thing with my oil gauge, got mine off ebay and was the closest thing to looking like a smiths one. Do you have the old gauge for a comparison? Should look great when installed, good job. Gareth Quote Link to post Share on other sites
KiwiTR6 Posted August 24, 2023 Author Report Share Posted August 24, 2023 I think it would have looked better Gareth if I'd been able to use the Smiths front half-plate, but the thickness of the flange on the new gauge prohibited that. I would also have ended up with VOLTAGE displayed twice, which would have looked silly. Quote Link to post Share on other sites
KiwiTR6 Posted August 26, 2023 Author Report Share Posted August 26, 2023 Job finished with the gauge now installed. I'm pretty happy with it, certainly doesn't look out of place at a quick glance. The back light is a lot better than the incandescents in the other gauges although I do have LEDs for those to fit at some stage which may improve things. Quote Link to post Share on other sites
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