[Mgs] Jaeger Dual Gauge Modern Replacement Accuracy & Calibration

[Robert J. Guinness]

Thanks Paul, helpful as always.  The Vendor did offer a refund if I 
shipped it back.

On 7/20/2020 10:28 AM, PaulHunt73 wrote:
>  e-mail signature
> No you aren't, and they would say that as it's obviously their gauge 
> that is faulty.  Installed I can't see cooling system pressure 
> squeezing the bulb enough to boost the gas pressure and hence the 
> gauge reading anywhere near 20 degrees.  I don't know the correlation 
> between pressure and reading, but it may be similar to the oil section.
> I have often wondered whether the long (in an MGB at any rate) 
> capillary tube being alongside the head in the engine compartment does 
> add a little to the reading, as all the tube there could be at 
> 100-plus degrees F in hot weather compared to less than 30 degrees in 
> very cold weather, with the bulb - presumably with a correctly working 
> stat - being at 180F in both cases.
> If you were in the UK I'd say demand your money back as it's not fit 
> for purpose, there are consumer protection rules, less easy if you are 
> in another country.  So many people these days just moan and don't 
> demand corrective action, so there is little incentive for suppliers 
> to up their game.  The simplest thing is to be aware of it, and take 
> the same action when it reads 190 that you would at 212.  Moving the 
> needle could cause damage, but there may well be some negative reading 
> that the stop prevents that would mean it wouldn't be 20 degrees off 
> the stop when cold.  To me though, it would be more irritating to see 
> that, than taking account of known under-reading, as I find in both my 
> cars there can be significant differences in 'normal' running winter 
> and summer'.  Unlike modern cars which I believe are computer 
> controlled to prevent owner paranoia with 'normal' variations.
> PaulH.
>
>     ----- Original Message -----
>
>     I bought a new "Jaeger" dual gauge for my MGA  from a vendor in
>     England.  ...  The new gauge never got over a hairs width beyond 190.
>
>     I called the vendor and they intimated that I was crazy to test it
>     the way I did.  Am I?  Is there a better way to test it without
>     installing it?  Or is installation and an infrared thermometer a
>     preferable way to test it.
>
-- 
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Robert Guinness

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