Re-routing cooling system at SOHC?

Off topic:

I am a little bit disappointed, because you keep repeating two things:

My x1/9 blah blah blah, ignoring that the heat that is produced during the heat exchange at radiator, is in a completely different compartment at the Xes, so yes maybe Xes suffer less than FWD cars.

Second check your cooland system etc...
Again I have already said that there are many ways to improve the cooling system without re-routing.

The point of the topic was to discuss about the pipe that is connected to the water pump and a possible re-routing, but I do not see from the majority that there is a mood for discussion.

ON topic:

It was pointed that we should not use head as an import point, because the water will escape quickly without truly cool the block.
Also my idea of using the water block plate behind the flywheel, may end up to same result.

Two new approaches:
use the water block plate behind the engine mount ( it will be a lot trickier )
or re-manufacture the pipe and the exhaust manifold with a less heat conductive material, like stainless steel.
 
stayros32001 said:
Off topic:

I am a little bit disappointed, because you keep repeating two things:

My x1/9 blah blah blah, ignoring that the heat that is produced during the heat exchange at radiator, is in a completely different compartment at the Xes, so yes maybe Xes suffer less than FWD cars.

Second check your cooland system etc...
Again I have already said that there are many ways to improve the cooling system without re-routing.

The point of the topic was to discuss about the pipe that is connected to the water pump and a possible re-routing, but I do not see from the majority that there is a mood for discussion.

ON topic:

It was pointed that we should not use head as an import point, because the water will escape quickly without truly cool the block.
Also my idea of using the water block plate behind the flywheel, may end up to same result.

Two new approaches:
use the water block plate behind the engine mount ( it will be a lot trickier )
or re-manufacture the pipe and the exhaust manifold with a less heat conductive material, like stainless steel.
Click to expand...
I see you are operating under the hypothesis that ambient heat (partly radiated from the exhaust manifold and partly convected from ambient air in the rear of the engine compartment) is being introduced into the coolant thru the metal pipe that feeds the water pump (which I'll call a crossover pipe), thereby undesirably raising the temperature of the coolant returning from the radiator. Based on this hypothesis, you are interested in how to re-route the coolant flow to avoid this heat.

We will not consider whether or not this hypothesis is true, nor will we conduct tests to determine whether or not altering any other aspect of the cooling system would achieve compensating results.

Let's just concentrate on the crossover pipe--how do we keep it from absorbing heat. First, block the sources of heat impacting on the pipe; second, reduce the pipe's ability to absorb whatever heat is there. Ceramic coatings are likely the answer. One type of ceramic coating is mostly intended for exhausts, its function is to block heat from escaping from exhaust manifolds/pipes. Applied to your exhaust manifold and downpipe will cut down on the amount of heat transferred from the exhaust to the crossover pipe. This would only address one half of the equation, heat from the exhaust into the crossover pipe. The other half would be a different type of ceramic coating for the crossover pipe itself to reduce its ability to absorb heat from external sources. Without making a major change in the cooling system architecture.
 
stayros32001 said:
ignoring that the heat that is produced during the heat exchange at radiator, is in a completely different compartment at the Xes, so yes maybe Xes suffer less than FWD cars
Click to expand...
Actually I'm of the belief that the X has a more difficult time keeping temperatures in check than the 128. The front mounted radiator is a LONG way from the rear mounted engine, with two VERY long (and skinny) pipes connecting them. That puts a huge strain on the water pump. Not very efficient. Plus the X has a rather small radiator due to the low height of the car's nose (but I don't know how the 128 radiator compares in size). Also the location of the X's engine behind the cabin places it in a small enclosed box that traps a ton more heat than the front mounted 128 engine compartment.

I think the comments stating the X doesn't have a cooling issue are from those that happen to be lucky and don't have issues on their particular car. Could be a function of the climate they live in, how they drive their car, the condition of everything, any changes they have made, the performance level of their engine, or who knows what else that might be different from those that do experience cooling issues. The important point is there are some that do experience cooling issues despite everything being in excellent condition and working properly - regardless of why. And for them improvements are very welcome. :)
 
I have not had a moment to read the thread in great detail, but regarding OPs concern of the heat exchange between the hot exhaust manifold and the coolant feed pipe:

Yes there will absolutely be heat transfer here, but maybe not as much as you'd expect. However, there's one thing: during the conditions where the cooling system is most strained (low rpm, sitting in traffic with low airflow, etc) the flow rate through this pipe will be low, and as the heat is a consistent source, this means a larger amount of energy being put into the coolant.

BUT. You can pretty much make this negligible with some heat shielding, or a wrap, as Dr Jeff suggested early on. This should pretty much entirely eliminate the routing of this specific pipe as a concern, and there's plenty of cost effective options for going about this.
 
Jonohhh said:
I have not had a moment to read the thread in great detail, but regarding OPs concern of the heat exchange between the hot exhaust manifold and the coolant feed pipe:

Yes there will absolutely be heat transfer here, but maybe not as much as you'd expect. However, there's one thing: during the conditions where the cooling system is most strained (low rpm, sitting in traffic with low airflow, etc) the flow rate through this pipe will be low, and as the heat is a consistent source, this means a larger amount of energy being put into the coolant.

BUT. You can pretty much make this negligible with some heat shielding, or a wrap, as Dr Jeff suggested early on. This should pretty much entirely eliminate the routing of this specific pipe as a concern, and there's plenty of cost effective options for going about this.
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If your vehicle is overheating by heat transfer from the coolant transfer pipe to water pump you have a “bigger” issue somewhere else!!!
 
Stuartc said:
If your vehicle is overheating by heat transfer from the coolant transfer pipe to water pump you have a “bigger” issue somewhere else!!!
Click to expand...
Agreed. I can't imagine the difference in inlet temperature being more than a degree C or two.
 
Have a look at this thread... It's about isolating carbs from exhaust heat, but it's the same principle... I've had very good results using the Swain Tech Coating and some advanced Aerospace insulating materials... I don't think you need to reroute that pipe.. I would Swain coat it, and make a Heat shield between the exhaust and the pipe with some aerogel or similar insulation on the underside... The only benefit I can see from an electric water pump is it won't slow down at idle, in traffic. I used a cogged belt instead of a V-Belt on my pump for 2 reasons.. 1, I can get the belt on and off without removing the WP pulley. 2, It only requires 5 or 6 lbs. of tension, so there's less drag and power drain on the engine(also better for the WP bearings) This is on a 128, and I'm in Los Angeles, it's pretty warm here too...

Header wrap

A ceramic coating optimized for heat insulation can and will reduce radiant heat pretty moderately - but not all types of coatings provide this benefit, and quite a few coatings on the market don't. It's actually possible to get the cylinder head combustion chambers ceramic coated to yield an...
xwebforums.com
 
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A simple improvement for the OP would be to change the colour of the coolant pipe from black to silver, making it less prone to absorbing radiated heat.

I found that my X benefitted from cleaning the crud from the system and optimizing the water pump housing/impeller clearance.
 
The general consensus here is that relocating the water pump pipe is actually the last solution to consider since it's not easy to do and none of us have ever done it.

Stayros wants us to stay focused on changing the pipe but maybe he has target fixation on that as a solution.

Let's not chase down a problem that may not actually exist. Has anyone tested how far the heat from a header pipe radiates? Heat rises, is most of the heat coming off the header pipes going up (to cook the intake) rather than cooking that cooling pipe? Does all the heat wraps and coatings actually solve the issue?

There really isn't any room in a 128 engine bay to reroute the header pipes further away from the cooling pipe so no solution there. I went to look at a 128 sedan that was being prepped as a drift car of all things and it had a big ass cowl induction hood scoop. I bet it would have vented a lot of engine bay generated heat with the car sitting in traffic.

If Stayros wants us to stay focused on reconfiguring the coolant pipe I fear that we just can't provide much help.

My only input is to reroute that pipe so it comes out of the water pump, goes straight down, then runs laterally along the outside of the oil pan and then makes another 90 degree turn to go back up to the thermostat. And no I wouldn't actually bother doing that.
 
I don't believe there is much heat effect from exhaust to the water pipe in question.

On my car I have electric water pump (for both hoping to gain 1 or 2 hp and fix idle heat rise), part of this is I have replaced this pipe in question with a stainless pipe that includes the 90 turn to the block. Replacing the mechanical pump completely. My pump goes between thermostat and this new pipe, replacing the short 90 rubber hose.

That said, one way to reroute would be to do as I have done, but route the pipe from the thermostat to an eclectic pump, to whatever route you like and make a straight pipe directly to the block, again replacing the mechanical water pump.

On an X1/9 this could go via the rear boot. On a front engine car looks like you have plenty of space to route a hose around the firewall.

I don't see why this couldn't be done, but it seems like a lot of work for small if any gain.
 
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The most common problem with the pipe that runs from the coolant pump to T-stat housing is pin holes that develop due to corrosion. These pin holes cause a slight air leak into the cooling system which causes mysterious cooling system problem.. Not often considered possible problem area in the cooling system.

As for heat transfer from the exhaust to that coolant pipe, would be nil due to the fact air is a surprisingly good heat isolator and the exhaust systems in a normally aspirated motor is simply not that high compared to a turbo exhaust system. Is the motor in this exxe being run at full throttle 100% power output for hour after hour, then maybe a problem..

Lampredi and the folks at Fiat understood this problem and why there is significant air space between the exhaust system to that coolant pipe.

Before trying to re-design, re-engineer any aspect of the exxe, fully understand the original design problem and how/why the design/engineering folks solved these problems. It is simply ignorant-arrogant to believe Lampredi and others involved with the original design did not fully understand what they were designing and why they did what they did.


Bernice
 
Clearance gap between the coolant pump impeller to housing does impact coolant flow at idle or lower engine speeds. This is why there is a spec for this in the Fiat service manual, check this as the current crop of "aftermarket"coolant pumps might not meet this spec once installed on to the coolant pump housing..

As for reducing motor power loss by using an electric coolant pump, yes, but that energy has to come from some where. ... that some where will now be the electrical system instead of the petro motor..

There is no "free" energy, as energy has to come from some where..


Bernice
 
I'm with Rupunzell on this one. An X1/9 cooling system in proper working order will do its job. I've fixed many an X1/9 that was overheating and it was always fixable without the need to shade-tree engineer a new cooling system. Clogged radiators, bad thermostats, wrong thermostats, hose nipples in the thermostat housing nearly rusted shut, owners never bleeding their radiators, water pump impeller to housing gap being too large, raditator fans not working (bad fan or themoswitch dead), wrong expansion tank cap (too low pressure), cracked expansion tank nipple, timing being way off. Once sorted, the cars will not overheat. So no, this isn't only my magical car, oh how lucky I am to have the one X1/9 ever made that doesn't overheat. None of my many X1/9s overheated over the last 37 years once they were sorted out. FI or carb'd. Even hotrodded out, like my '74 with dual DCNFs, cam, '74 exhaust manifold, high compression pistons, big valve head, doesn't overheat on 95 degree days. This car has gone through three different engine configurations over the decades, FI, FI HotRod, now dual carb HotRod. No chronic overheating.

If your X1/9 overheats, find the problem and fix it. If you find joy in re-engineering your car, then by all means enjoy, it's your car. But I don't buy the claim that it's flawed by design. My experience doesn't support that conclusion. The only conclusion my experience supports is that these cars are decades old and need sorting. Once sorted, they work just fine without re-engineering.

As for heat transfer physics, fluid flow is a major driver in heat transfer. The faster flow will transfer more heat, not slower flow. So increasing the flow rate will improve heat transfer. If you're concerned about heat radiating from the exhaust on the pipe, then wrap the pipe. I painted mine silver and also painted my son's '86 silver, black absorbs radiation big time.

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Rupunzell said:
As for reducing motor power loss by using an electric coolant pump, yes, but that energy has to come from some where. ... that some where will now be the electrical system instead of the petro motor..

There is no "free" energy, as energy has to come from some where..
Click to expand...
You are completely right, I have read online about the power loss from a water pump but obviously replacing with an electric the power has to come from somewhere. I guess it is about efficiency and to be honest I have no idea which is more efficient overall.

My thoughts on the matter are the main win is a constant flow of coolant over a mechanical pump which changes the flow with engine speed. So hopefully less turbulence in the coolant flow. I never tested if it actually makes any real difference, but I like it and its easy to do.

What I really enjoy is in an old car coming to traffic and watching the engine temp drop a little rather than creep up a little. Also I can leave the pump running after the engine has stopped to avoid the coolant boiling after a spirited run, but then again I have an uno turbo engine.

I tired just answering the original question, but I don't think it needs doing. To solve rust/pin holes in the pipe in question I replaced with a stainless pipe, which may also reduce heat absorption.

The only ferrous metal I have in my system is the engine block and the heater core and I still seem to have gained some rust. Time for me to do another flush and coolant renew but that is another story.
 
Alex(UK) said:
You are completely right, I have read online about the power loss from a water pump but obviously replacing with an electric the power has to come from somewhere. I guess it is about efficiency and to be honest I have no idea which is more efficient overall.

My thoughts on the matter are the main win is a constant flow of coolant over a mechanical pump which changes the flow with engine speed. So hopefully less turbulence in the coolant flow. I never tested if it actually makes any real difference, but I like it and its easy to do.

What I really enjoy is in an old car coming to traffic and watching the engine temp drop a little rather than creep up a little. Also I can leave the pump running after the engine has stopped to avoid the coolant boiling after a spirited run, but then again I have an uno turbo engine.

I tired just answering the original question, but I don't think it needs doing. To solve rust/pin holes in the pipe in question I replaced with a stainless pipe, which may also reduce heat absorption.

The only ferrous metal I have in my system is the engine block and the heater core and I still seem to have gained some rust. Time for me to do another flush and coolant renew but that is another story.
Click to expand...

To do the electric coolant pump proper demands a number of well placed temperature sensors, a means to sum up the temperature data then apply a controller with a proper temperature range window with the needed time delay for control loop stability. Doing this properly is a LOT more involved than simply installing an electric coolant pump with a "black box"...

As for the traffic temperature rise, that is what the thermostatic switch in the radiator, fan relay is for.. and the control loop for this temperature regulation system has been worked out, does what is intended.

If you're paranoid about temperature rise during extended traffic stops, add a manual control switch for the radiator fans. Turn the fans on if the temp gauge becomes a "worry"... far easier than going the electric coolant pump route..

Item of primary concern would be the turbo, cooling the turbo after a hard run is stressful on the turbo bearings, tends to cook the oil on to the turbine shaft bearings causing all sorts of problems.. Depending on the turbo, they are oil cooled/lubricated. In time, turbos got coolant cooling. This helped, but cooling only happens if there is coolant circulating around the turbo's cooling passages, or the coolant flow terminates once the motor is off. SAAB had a very nice and elegant solution to this problem. SAAB designed a thermo siphon system based on temperature difference between turbo's cooling passages -vs- temperature in the cooling system. Long as there is significant temperature differential, coolant circulates, circulation stops once the temperature difference equalizes. Other brands often use a small electric coolant pump plus temperature controller to run this coolant pump after the motor is turned off to continue circulating coolant in then out of the turbo to cool it off. Notable, Some Mini's sold in the USA had a recall for electric turbo coolant pump failures.. which caused the turbo to fail...

The old school solution to cooling off the turbo soon after the motor is switched off, allow the motor to idle down cool off before switching off the motor.. Keep in mind, there will be heat soak to deal with once the motor vehicle comes to a stop. Having watched countless LeMons race cars come in HOT.. for a stop, then refuse to start up and lots more.. the heat soak problem is very real and can be very serious.. Road cars, not so much as the heat load on road cars is no where near what an endurance race car deals with in 100+ degrees F track conditions.

Honestly, the heat generated with the motor at idle is simply not that high compared to a race motor being run at nee full throttle, nee full power in race conditions and high ambient temperatures. Oh, air density based on altitude/elevation has a strong effect on cooling ability..


Bernice
 
Rupunzell said:
To do the electric coolant pump proper demands a number of well placed temperature sensors, a means to sum up the temperature data then apply a controller with a proper temperature range window with the needed time delay for control loop stability. Doing this properly is a LOT more involved than simply installing an electric coolant pump with a "black box"...
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Bernice I always appreciate what you have to say

Also I feel we are drifting off topic. However for completeness.

What I currently have is the pump running at 100% when the key is in position 2. As it is placed between the exit of the thermostat housing and the water pump entrance to the block, I allow all the thermostats to do their job and the coolant flow is the same as stock. No black box. Only change is the flow is faster at idle, but I have not seen any issue with this.

As a monitor I do have an additional coolant gauge that goes to a sensor at the radiator. So you can see the thermostat opening on the gauge and see rad temp vs engine temp.

This does mean after a hot run the coolant is passing through the turbo as if the engine was running. You can see the coolant leave the turbo as it goes directly to the expansion tank. Thinking about it maybe I have rerouted some of the coolant hoses. Heater core return also goes directly to the expansion tank.

I tried different speeds with a manual PWM circuit at different time but it didn't seem to make a noticeable difference, except too slow gets hotter.

If I was to make the choice again I might be persuaded to keep the mechanical pump, but as I have it all in and working, and working well I will leave it as it is. My engine temp is more consistent. What I have seems to work.

I have however recently moved the car to a hotter environment (UK to Tenerife) so I will see how I get on with a higher air temperature.

Alex
 
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