mk1-forum.net

What is the differences between Temperature Sensors GTR 104 & GTR 101?

Are they colour coded have part number stamped on them?

Does anybody know what the resistances value should be of both sensors at Cold, Normal, Hot?

Thanks

GTR101 temperature transmitter

cross reference

Lucas SNB103

smiths TT3803/00A

WTT3



thread 5/8 " x 18UNF


applications include

INNOCENTI

Mini 90 1974-82

Mini 1000 1972-75

Jim1071 wrote:GTR101

Mini 90 1974-82

Mini 1000 1972-75

That makes it needing a voltage stabiliser - but 10 volt or 5 volt I wonder.

I know early cars (59-62) had an unstabilised 12v feed to the instuments. Then a 10 volt stabliser was used (fitted to the back of the speedo).

Later still (maybe in the 70s) a lower voltage was used ( 5 v ??).

As far as I know senders, instruments and stabilisers cannot be mixed.

To the best of my knowledge no Smiths gauges ever ran on 5V. A number of American cars (like Jeeps) use 5V gauges.

Sorry... I don't know anything about the various temperature sending unit calibrations and applications.

I have an issue with my temp gauge which is correct to the 1961 year of the car .. on first fire up of this rebuilt engine the temp gauge quickly shows red hot, irrespective the actual engine temp is about normal.. my temp gage is not going to earth & the car has a new autosparks harness & the new minispares temp sender has a red core .. maybe the temp sender is incorrect & is my problem .. so can i ask does anyone now the answer to the sender resistance question

For the early electrical gauges (pre mid-'64) the gauge must have a good earth connection. If your harness doesn't have an earth wire, make one with a ring terminal on the gauge end. The ring terminal should be placed over the mounting stud on the gauge before the thumb nut is tightened to securely mount the gauge.

You can read up on the early gauge system and adjust your calibration to suite by following the information on Barney Gaylord's MGA Guru website. Read through all the fuel gauge section I post the link to below. The early electric fuel and temp gauges work the same as each other so the information is relevant.

http://www.mgaguru.com/mgtech/electric/fg_01.htm
http://www.mgaguru.com/mgtech/electric/fg_01.htm

Colour information as follows:

GTR102 - Green Insert. Used up until 09/64 when the voltage stabilisers were introduced. Smiths marked TT-3800/00A, Intermotor 5270
GTR104 - Red Insert. Used from 09/64 until 1969 with voltage stabiliser. Smiths marked TT-3802/00, Intermotor 5271
GTR101 - Black Insert. Used from 1969 until 1994 with voltage stabiliser. Smiths marked TT-3803/00A

Resistance (temps estimate only - ie measured out of box and then after held in hand until warm):

GTR102 Green (actually 2 x NOS Intermotor 5270), 300Ω @12˚C, 200Ω @35˚C
GTR104 Red (actually NOS Intermotor 5271), 580Ω @12˚C, 450Ω @35˚C
GTR101 Black (actually used Smiths TT-3803/00A), 725Ω @12˚C, 520Ω @35˚C

Polarsilver, unfortunately Minispares don't have the correct sender for the early non-stabilised gauge. You need the green one. They are hard to find but you may get one through eBay or similar.

Since the green sender is not easily found, how about using the later black sender with one of Chris' (Spiyda Design's) Gauge Wizard boards to match the sender to the gauge?

https://www.spiyda.com/magento/index.ph ... d-mk3.html

Green senders still listed by some suppliers:

http://www.somerfordmini.co.uk/eshop/in ... ts_id=5170

http://www.leacyclassics.com/gtr102.html

Polarsilver wrote:I have an issue with my temp gauge which is correct to the 1961 year of the car .. on first fire up of this rebuilt engine the temp gauge quickly shows red hot, irrespective the actual engine temp is about normal.. my temp gage is not going to earth & the car has a new autosparks harness & the new minispares temp sender has a red core .. maybe the temp sender is incorrect & is my problem .. so can i ask does anyone now the answer to the sender resistance question

A 1961 car has unstabilised instruments, so the temp gauge, like the fuel gauge, should jump instantly to a reading.
The slow moving (damped) gauges only fit car with a voltage stabiliser.
I wonder if you have the wrong gauge.

Thanks to all for the advice.. i have put my order into Somerford and they have GTR102 early type Temp Senders in stock ... so now i have 2off on delivery.
Also asked Somerford what Japanese Rubber parts they can now supply .. their stock is limited to steering rack gaiters & CV Boots..

As far as I know senders, instruments and stabilisers cannot be mixed.

that is 100 percent

Temp Sender on my 66 1275 S is coded :

15 UK Made 03F2