alanrichey

The Rover manual agrees with you, pump takes water from bottom hose and pumps through engine block and inlet manifold before coming out underneath the thermostat. No, Red line appears to be permanently open All under water, particularly when engine running when expansion tank appears to be full. Sounds logical. I guess I could try temporarily blocking the red and blue lines out of the top of the radiator,

OK, you asked for it so here it is Obviously everything in black is a standard core system used by all cars. The Green pipe running from above the thermostat to the top of the expansion bottle is standard Rover design and allows the coolant to expand into the bottle The part of the red pipe that runs from underneath the thermostat to the expansion bottle is also Rover standard and I assume that is the return path for the coolant when the engine cools off. In a normal Rover the rest of the red pipe feeds the ancillaries (Heater, aircon..) but in the Superpec it goes across the top of the engine and into the top of the radiator. I have no idea why, but the presence of the bleed valve leads me to believe it to assist in filling the system. And I have absolutely no idea what the blue pipe on the left is for. Maybe the radiator (anyone know what it came off ?) had a spare outlet on the opposite end of the top of the radiator to the top hose, and the expansion bottle also had a spare inlet so RHE just decided to join them with a tube ? That's all I can figure out.

This thread has become so contentious I was going to shut up and go back in my box. But maybe one last thing. No-one has yet explained to me why my theory is incorrect. We have to remember my thermostat doesn't suddenly snap open at 88C and snap close if the temperature drops to 87C, it is a very gradual process over 10-12C. As I see it, my engine starts to warm up until the thermostat starts to open at 76C (Actually if I look carefully at my graph I think that happens at 73C, probably just down to manufacturing tolerances). At this point water starts to flow through the thermostat and is cooled by the air flowing through the radiator. Now, if by the time the temperature reaches 78C the thermostat has maybe opened about 30% and the resultant flow of water and the cooling via the radiator is sufficient for the system to reach a steady state so it remains at that temperature. What I have done by masking the grill is to reduce the amount of cooling air going through the radiator so that the thermostat is forced to open a bit further to allow more water to flow through the radiator and so the steady state raises to about 85C. Where is the flaw in that logic ?

Maybe up to 45 degs but I don't think so at 70 degrees

I don't want to get into a slanging match about this, but if I quote directly from the Rover manual "..Thermostat starts to open at 76C, and is fully open at 88C.." you will see the top of the rad will start to warm up well before the Stat quoted temperature.

Have to admit my 88C thermostat, bought from Rimmer Bros, does have the 'jiggle' hole in the stat. So maybe I should try another thermostat without the hole ? I didn't realise this subject would cause such a heavy reaction, but in my defence can I reiterate that I have made NO modifications to the basic plumbing, it is exactly as it left the Robin Hood factory in 2001 .

Sorry Jim but I don't think you can compare the Superspec with a 'normal' 2B. Although the pipes are routed differently to the Rover 420 (because the engine, radiator and expansion bottle are mounted in different places) looking at my Haynes manual it is still fundamentally the same system. And I haven't made any modifications to the cooling system. And as I said before, our radiator is almost twice the size of any normal one (including the 420), but angled back almost 70 degs to compensate. The Superspec doesn't have a heater fitted so that is not a player in the equation. The only major difference is that Richard Stewart fitted an extra pipe from the top of the radiator across the top of the engine (with a bleed valve brazed on) into the expansion bottle, as the bottle is almost level with the top of the radiator. I suppose you could get reverse flow through that pipe from the expansion bottle to the top of the radiator, but it is a very narrow bore. Anyway, bottom line is that for the first time in 3 years I seem to have a perfectly working cooling system so I don't really care how it is working, I'm just enjoying driving around without having to continually watch the temperature gauge

The long term story is that I suffered overheating problems for 2 years and tried everything, including, as you say, trying to force the air through the radiator (which on the Superspec is absolutely HUGE), and running without a thermostat, but at the same time found the coolant was also leaking under pressure from somewhere, One of the modifications I tried was to change the pressure cap from 13psi to 20psi and that resulted in a rather dramatic breakdown on the way back from last years end-of-season bash when one of the rubber cooling pipes blew off a stainless pipe. In hindsight I suspect that was where the coolant was leaking, as since I fixed that the leakage has been minimal. That was when the car started running very cool, mainly because it was full of coolant and with no thermostat, so I started playing with thermostats. So at long last I think I may be there and I will now remake the grill blank so it is a bit more adjustable for various conditions.

Pretty certain not. With no thermostat in the engine stabilised at 62C. With an 82C one in she stabilised at 73C. With an 88C in she stabilised at 76C. Now, with my partially blocked grid and the 88C thermostat I just got back from an hour-long drive and she stabiiised absolutely bang on 88C. Happy bunny

OK. I thought I had made it clear in the thread that I had already replaced the existing 82C thermostat with a new 88C one hoping that would cure the problem. It didn't, and the car kept running cold. My logic (probably incorrect as it has been in the past) was that although the thermostat is rated at 88C, that is the 'fully open' temperature, and apparently it actually starts to open around 76C. And in my case even such a small flow through the radiator was enough to keep the engine running at a temperature in the high 70s. So I needed to reduce the efficiency of the radiator and the grill blanking seemed the obvious solution. I guess I could blank off even more of the grill and then use the fan to keep the temperature down, but not sure there is much point in that if I already have the temperature close to ideal ?. Does that make any sense ?

't stat' ? Sorry, not sure what you mean.

Turned out engine was stabilising around 75C, which was still a bit too low. So as usual I followed Mick's advice (never let me down yet ), although I do remember doing this on my Morris Minor in the 60s. Couple of pieces of cardboard covered in baking foil, looks really smooooth And she is now running at a steady 85C. Fingers crossed. Al

I just mounted one of these onto the bulkhead in the passenger footwell. Still got one socket left

No need for wiring

Will be there in the kit if weather OK

Might be different for you, but on my Rover engine I have 2 temperature sensors. The one for the ECU is just below the thermostat so it is actually measuring the engine temperature straight away, and the one for the gauge is just above the thermostat so it registers the correct temperature only after the thermostat has opened. .

And here it is, before and after. Very nice, the buckle now sits dead central over the stomach and I have an inch of adjustment in both side straps. Thanks Andi, good call.

The Superspec came with the middle section of the dash angled back about 10 degs so the instrument cluster (Escort) was close to right-angles to your vision when you looked at it. One of the few good things about the car Highly recommended if you can do it.

Pencil me in as well

Some months ago Richard Stewart was selling off some Daytona parts he had left over, on E-Bay. Not sure if they sold, he may still have quite a lot left.

I just ran my DRLs through a 'Normally ON' relay with a feed from the sidelights to trigger the relay to OFF when the lights come on.

Hopefully I will never need to go near it again. I'll just set it at 2-3" and that will give sufficient adjustment at the buckle itself.

That looks good as well. I might get one of those as well as the passenger belt doesn't have much spare in it.

Found this on E-Bay. 4.5mm but should be perfect I think.