Correct temp gauge/sender/voltage stabilizer combo

[abri]

Greetings,

I’m trying to confirm what the correct combo is for a 66/67 1275 Cooper S.

What I have is a BR1310/00 stabilizer, TT3802 (Smiths part number, equivalent of GTR104 Unipart) sending unit and a factory original gauge.

Can anyone confirm if those stabilizer and sending units are correct?

Thanks
Abri

[Simon776]

A 1966/67 car would have a BR1305/00 stabiliser.

So far as I know, the only difference between them is that a BR1305/00A has 4 x male connectors and BR1310/00 has 2 x male 2 x female connectors.

[iain1967s]

Photos attached of what I used. The white sender is sold as a modern repro of ‘red’ GTR104 [equivalent of Smiths TT-3802/00], the black one is a NOS genuine Smiths TT-3803 [aka GTR101]. More details with my test results here: viewtopic.php?f=3&t=22709

GTR104 was supposed to be the correct part for my ‘67 S, but was reading around 1/4 scale too high - between N and H on the gauge. The TT-3803 was a more accurate match, sitting just below N. Of course it really depends which thermostat you have fitted, as to where ‘N’ should be on the gauge.

There is a wide tolerance so it’s not a particularly accurate system over all… you can pretty much use any combination of the three thermostats and two senders, and the gauge will sit somewhere between 1/4 and 3/4 in normal running. I think that is why the ’N’ range is so wide on the gauge face; it seems that consistency is more important than accuracy.

Original 1967 S standard spec per AKD3509 page MA-57 has the 82° thermostat with GTR104, then using 74° for hot climates and 88° for cold climates. But modern unleaded fuel doesn’t burn as efficiently with lower temperatures, so 88° might be preferable all round…

From my testing, using a 74° thermostat is a good match for ‘red’ GTR104 / TT-3802, and an 88° thermostat better matches ‘black’ GTR101 / TT-3803. For 82°, neither sender matches exactly; I used the black simply because I trust NOS more than repro parts.

[Dan Tweed grey]

I spent a lot of time fannying around with senders, none of the available new senders where correct for my '65 cooper.
I actually bought a cylinder head from an auto jumble that had a sender in it and it worked perfectly.
My advise is find an old sender to sort most problems.