Water Temp

[rgh0]

Hi John
I agree the hole would also allow trapped air to get out also which is also needed

cheers
Rohan

[Chancer]

Prezoom.

Been there done that with a Zetec 7 conversion in the last century!!! I was using a Redline water rail, looked great but was awful for cooling and temperature control for the reasons that you mention, cant believe that all these years later nothing has been learned, the standard Ford set up is far Superior but conversions using that look DIY'ish compared to a water rail.

I had all the problems that you envisage, I could see the actual cylinder head and engine block temperature and it would go off the scale during warm up and my feet were still cold, eventually the stat would open and the temps would reduce and stabilise but regulation was always poor.

Ironically it was the rising heat from the exhaust manifold that would finally convince the thermostat to start to open, it was at the end of a long dead leg in the water rail far away from the block/head temperature, driving from cold straight onto a motorway was very problematic as the exhaust heat was blown away from the water rail.

I eventualy solved the problem by drilling a hole in the thermostat to allow some circulation when it was closed, from memory it ended up being a lot bigger than I was happy with in order for it to work which in itself increased the warm up time.

[prezoom]

The original thermostat from my engine has a small hole, with a BB to close it off when the thermostat opens and water starts to circulate. An aftermarket thermostat I purchased does not have that arrangement, and I will be returning the part. May take a trip to my local Ford dealer for an original part.

In addition to the original design, the top of my water rail is higher than the head and the radiator. To bleed any trapped air, I drilled and taped a hole for a standard brake bleed fitting. It bottoms in the hole to close off a 1/8" through hole to the backside of the thermostat. The expansion tank, which contains the radiator cap I fabricated, will have a water level higher than any other part of the system. Trying to check all the boxes.

[freddy22112211]

As my sprint always ran nice and warm, I once tried it without the thermostat. Seemed to work fine, and I drove the car from then on without a thermostat. Temperatures were the same as with a thermostat, perhaps a shade better cooling.
Gordon