Thread: Thermostat 3.5lt

Thermostat 82degs. Cap 15-16psi.

If you run 82 c you are likely in Victorian winter to run below 82 c which is the point that most injections enrich.
While the old flapper does not have progressive enrichment, the thermo time switch could enable the cold start injector.
I am not an expert on the flapper but I have studied Federal and 14CUX a lot and both switch at 82C.
I really recommend you stay with the standard 88C which gives plenty of headroom for cold days and is cool enough for hot days.

82C is fine for carbys (and TD5s.)
Regards Philip A

Cold start Injector only operates during cranking.
That's what I was taught anyway???

OK so I consulted the book"Bosch Fuel Injection and Engine Management by Charles O Probst,SAE" to refresh myself. The Lucas is a Bosch L Jetronic copy and has Bosch components.
On Page 16 referring to L Jetronic it shows a graph of resistance of the temperature sensor reaching 400 Ohms at 80C.
para 4 on that page states among other things

If the control unit applies a fixed voltage to the NTC ( Negative Temperature Coefficient) resistor , it will receive a smaller signal back as input from a cold resistor with higher resistance than from a warm one. From a cold resistor with high resistance than from a warm one. From a cold input signal, the control unit willcompensate by adding to the basic pulse time as shown in Fig 3-32.

So in short it works the same as a 14CUX ( LH Jetronic) so in winter with an 82 C thermostat , the mixture will be rich . My obsevation is that in winter conditions a V8 can run maybe 5-6 C under thermostat opening.
So fit an 88C.

Regards Philip A

One of my cars has a very accurate digital temperature gauge. I fitted a new stant thermostat and noticed it would spike too 98degrees before opening, then regulate to ~70degrees (that is an 82degree thermostat). I ended up buying another 4 Stant ( US made ) thermostats, they all did the temperature spike before opening and all regulated to 5 -> 10degrees less than there rating.

I ended up buying a chinese made thermostat from somewhere else, it didn't spike, but regulated to 78degrees (not 82) ... sigh ... I decided "close enough". The 10year old thermostat I chucked, always regulated to exactly 82degrees, and never spiked the temperature prior to opening.

I think I fitted an 82degree high flow thermostat to the Rangie, as that's what the data sheet said to use. It's temperture gauge is useless as tits on a bull though. I know just under 1/4 of a gauge is normal running temperature ( 80degrees ??) if it was to reach mid point of the gauge (where it should sit) I would likely be getting very concerned, as that "could" be overheating.

seeya,
shane L.

I really enjoy getting such a descriptive answer to my questions. Thanks.

I guess the obvious question is if the cold start injector is firing in winter, how much more fuel am i likely to use? As a side thought, if the perfect fuel air mixture is 14 parts air to 1 part petrol and cold air is more dense having the extra injector running could be considered a befit?

It is a benefit, but only if you live in Sweden or the UK in a bad Winter.
The car doesn't run with a Cold Start Injector. It is only for starting.
Rangie/Disco's (early ones) have a tendency to run rich anyway, If it does run rich, suggest an Injector clean (the 8 normal ones!) and maybe some carby cleaner through the Plenum and Throttle Body and AFM etc.
My Cold Start Injector is disconnected and my Thermotime switch is also unplugged. Car runs and starts fine.