This is the OS stat
Still wondering if CC take the metal parts out and insert them into the alloy housing -
The milled section you show in your photo is in the same area as the OE heater return line which returns water post heater matrix to the engine side of the stat, however in your photo is looks like this is incorporated to act as a constant flow of return coolant from the radiator.
This coupled with the lack of an effective bypass equates to what your seeing, over cooled and then temperature spikes as the stat cannot respond in the correct timely manner as there's no bypass to effect this, instead its relying on a much slower heat source from the tiny bleed via expansion bottle.
All in all a poor set up.
The stock Ford / Cosworth worked perfectly well in high output application, I'm just 38 BHP shy of 620 with no problems at all running the 82 degree stat linked above and the OE bypass from rear of the head tothe pressed metal tube in the block, with my expansion bottle returning via the 16mm plastic feed on the stat housing above (no heater).
I also believe (but have not had change to confirm this) that the 630 runs stock crank and water pump pulleys.... can anyone confirm this..? as when you increase the engine speed beyond the road going redline of circa 7300 you overspeed the pump leading to cavitation which effects the efficiency of the coolant and means more work for the bleed into the expansion bottle.
Cosworth made oversize pump pulleys to slow this down allowing safe high rpm useage.
The other option is to use an undersize crank pulley but understandably CC wanted to keep the OE pulley as this affords more belt contact necessary for driving the Rotrex, and retains the torsional damper too .
Can I resurrect this thread as I'm having the same issue as the original poster. My car when driven, even in the summer constantly sits at 40C and only rises when stationary for example at traffic lights. Can this be right as I'm sure the car is over fueling at this temperature. Did anyone get any satisfactory solution from Caterham?
Below is my attempt of a schematic of the system in my car.
Driving 'The Fat One'
Have you checked that your temperature gauge is actually reading correctly ?
It appears to be ok as it does rise to around 80C and the fan kicks in when stationary
Also, with the positioning of the number plate by CC it virtually blocks any air to the oil cooler. Without a gauge it's difficult to know what temperature the oil is. There may be because of this a large difference between to two fluids.
Is yours a 620 too...?
Yes it is, on the front of this months magazine.
Re post #33 the red arrow on the left feeding the heater appears to flow in the opposite direction to the non heater variant .
On the latter this pipe feeds hot water back from the engine via the engine exit , vent and expansion tank , this recirculating hot water from the engine to the thermostat housing . I cannot see how that happens with this heater plumbing set up .
Swap p the colours on the plan ( cold should be blue ! )
On second thoughts maybe the flow on the diagram is just wrong . ( as well as the colours !)
cant see the diagram on #33...?