Monday, May 05, 2008

Water system ramblings


Been racking my brains. The side circuits are all good. Its what I wish to do with the main circuit.

I got the Rover SD1 2000 thermostat, you can see it below in the top hose.

Problem is its an 88C stat.

Too hot. Especially when you counter in the length from the head to the stat, the fact the water rail is alloy, the swirl pot is alloy I predict a 2-3deg cooling from radiation of heat bar when at full bore on the pump. That means the engine will 90-91C before the stat opens...having tested the stat on the stove it closes @ 87C and is no full open till 90c.

So I am binning this idea.
Shame cause its a neat item. Rimmer's sell these, but this item, there are some other part numbers and superceeded parts. Can't be bothered with messing with this anymore.

Also I have decided to run the normal water pump. No real reason bar I am not worried about the 2hp-5hp gain it seems to give on a 1300 Triumph engine. Also the fragilty of the K head with regards to overheating, pump failure etc. I do not really see any point in using it now...I'll leave the wiring and the control box and it could tested later if needed. I am sure it would do the job afterall its doing the job on many cars.
I think I will run the special PRRT Pressure Relief Remote thermostat developed for the latest K fitments and backfitting to the Lotus and MGF.

This is a thermostat that reads both pressure of the system and heat, so will open in two ways.

This special thermostat has a massive bypass, the same size as the main coolant lines. It works in two ways also. When coolant is warming and the stat starts to open it blends coolant from both main pipes (from radiator and bypass). When the stat is full open it shuts off the bypass and sticks all the coolant through the radiator.

If will be fitted where the EWP was. Below images show a Caterham fitted with a PRRT. Its basically exactly as mine would be fitted. I may need to just adjust the alloy water rail over the suspension tower, by putting a kink in the end, but may just need some extra hosing.

You can see the irovy coloured PRRT basically where my water pump is now.
The bypass comes off the top hose. Cunning method to get this big bypass running in my system is weld another 32mm beaded alloy tube into the side or base of my swirl pot. I already have a piece of suitable tube. This leaves some minor considerations.

First one is will the bleed line from the top of the swirl pot blow or suck when the bypass system is in full operation. As the coolant will be coming out the head to the swirl pot, and being sucked out the swirl pot back to the pump...Which will dominate, important as the bleed line on the top of the swirl pot is vented (currently) to fresh air in the top of the header tank?

So will flow along the line from the head (pressure) or flow back to the pump (suction) dominate when the bypass is operating...As my swirl pot bleed line is currently attached to the air space in the top of the header tank that could cause a minor issue until the stat is open. It could suck air through the bleed line out the header tank into the swirl pot. As such I will weld another JIC 4 take off below the water level in the header tank, so the swirl pot is not effectived by any reverse flow from its intended direction (out the swirl pot), so it can flow either way during warm up...These things must be considered, no issue when the stat is open at full bore, the swirl pot will work 100% as intended. This added take off can be blanked.

I will tap a stud into the water pump shaft so I can run the pump on a drill. This means I can test the water system statically before adding the timing belt and commiting to it.

It also means I need to weld another -6 take off to the header tank and one to the water rail on the inlet side..To move the evacuation line for the header tank to a new location. Again the old lines can be left in place for future use and blanked off with -6 blanking caps. So all in all there no real mods and I can easily test a few systems if needed.

Sorry to technical? Opps...

I think would be the ultimate reliable water system. Hate to backpedal on my concepts but I think its worth while as the PRRT is a better system that the standard or remote thermostats it also comes in different temps...

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