Fitting a heat gauge

Why a temperature gauge ?

Tee-OneTopics Article #26 p. 372 explains that heat gauges were abandoned with the setting of the big 6,75 engines. These engines were running at apparently very hot temperatures, scaring the customers. So RR preferred to hide this information. The lack of such an indicator is however frustrating and you might want to be aware of a temperature rise before it harms your engine.

Tee-One Topics Article # 81 p. 1122

So waiting to perform the actual change, I've started to gather informations on the subject, mainly from the Australian forum

Summary in French

1) un adpateur sur la durite haute (entrée dans le radiateur), c'est à dire un capteur qui nécessite de couper la durite en deux et qui vient se claer entre les deux segments.

2) Moteur de 1974 - une vis sans tête allen placée sur le tuyau d'admission du liquide de refroidissement (inlet collant manifold) à côté du logement du thermostat.

3) Parfois sur le logement de thermostat lui-même (pièce à changer) mais pas compatible pour tous les modèles (voir ci-dessous, logement de SSII source Ebay)

ici un thermostat pour SS I (Ebay).

Le capteur doit être  placé avant le thermostat pour mesurer la température une fois le thermostat ouvert (vers le radiateur). C'est pourquoi le sensor placé sur le logement (elbow) ne sert pas à mesurer la temp de l'eau.

Where to fit the sensor ?

Three parts are needed :sender, fuel gauge and voltage stabilizer.
The sender unit is normally the standard Lucas generic sender used in many brit cars of the peroid ( except Gm vauxhall and Ford )
You may be able to use the existing stabilzer which is working the fuel gauge but to save any problems its a good idea to fit a new stablizer (cheap and smaller than a match box).
Wiring
One terminal of the gauge goes to the stabilzer and the other goes to the sender. Green wires. Green with white tracer for sender.
The gauge case is earthed only so that the instrument light works. Black earth, red live from dash lights.
The stabilizer has 2 terminals. One to the gauge green and one to an ignition live source the green feed wire to the exsisting stabilzer. Do not connect to the exsisting stablizer output because you will have a stablzer running another stabilizer and the temperature gauge will read low.
Plugging the sender
 If the front area of the inlet manifold is examined you will notice various blanking plugs.
One of these goes directly into the bit of the manifold that connects the water jackets of the two cylinder heads together. This thread fits the sender directly. Which is very handy of RR to fit all V8s so that they can fit temp gauges if customer were to require one.
These parts are available new from Mini specalist and may even from LUCAS outlets. Sender:GBP 5;gauge:GBP 25; stabilizer:GBP 15 approx.
The wire going to the sender needs a BLACK sleave just to give it that factory look and sloder a spade with one of those neat clear plastic lucar covers crimped blue ones work well but look awfull.
Gauge and Ampmeter
An obvious for the gauge choice would be a Mini because of its soup-plate dash with an indentical looking in style to the fuel gauge. Could be put in place of the ampmeter.
The amp meter being the same style means that the gauge light will fit direct into the temperature gauge. Smiths or Lucas NOT VDO.
The amp meter is shunt operated which means that when the gauge reads say 30 amps there is not 30 amps going throug the gauge the shunt takes say 25 amps and the gauge 5 amps.
The two wires to the amp gauge are connected together and well insulated because they are LIVE ALL THE TIME.
Of course you may wish to fit in place of fag lighter or what ever else.
Ampmeter are handy but no amps is not going to wreak the engine where as overheat will.
(Message approved by david_gore)