Bongo Fury

On a slightly different track.

Does the ratio of coolant to water cause problems? Can "waterless coolants" be used?

Quote-
Waterless coolant virtually eliminates boil over in gasoline or diesels - the waterless coolant allows engines to tolerate running hotter, without boiling over, and allows the cooling system to run at very low or no pressure.

I know that differing ratios can cause changes to pressure and temps before the whole mix boils.

Any thoughts?

Bonza

Experiment 1 update

I had to join a ½ mile slow moving queue this morning on the way to work. This gave me plenty of time to watch the temperature readings.
When ever I was not moving the top hose and expansion tank hose temperatures were the same, when moving the top hose was always higher.
As I approached the end of the queue the Mason gauge was showing 12 o’clock / 50% and the hose temperatures were just over 60. The bottom hose was reading just above 20.
As soon as I got going (actually managed to reach 30mph ) both readings dropped, down to about 40 and 30 but the Mason gauge rose steadily to the running position of around 70%.

Conclusion

I need to protect the sensors from air flow.

However I think that I shall get similar readings on each and that will be around 60-65 most of the time. So I don’t think it is going to tell us much.

I really want to position them so that I can tell when the stat is open/closed or in a ‘balanced’ ½ way position so that I can see if things are approaching the pending disaster state. That is to monitor the ‘input’ and ‘output’ conditions of the cooling system as a whole, if the input temperature approaches that of the output then zero cooling = panic.

Regards Grahame

The Great Pretender wrote:

Grahame at work wrote:TGP - Yes I understand - so can we tell how much flow there is? to get the high pressure (relative) that you are getting and not reach the cap pressure on the 'downstream' side does this indicate a high rate of flow or a low rate of flow?

I shall have to go back to the begining of this thread and study it some more - I may be loosing the track

Grahame

The flow is the same throughout the system grasshopper, it is the speed that changes to alter the pressure.

I think we are getting confused about pressure here.

There are TWO pressures to consider. The background pressure in the system which is caused by the air in the header tank trying to expand as it heats up. This is governed by Charles Law and it goes up about 3% per 10C

Then there is the differential pressure caused by the pump and constrictions in the system.

In a normal bongo (not TGPs) the background pressure climbs rapidly as the header tank temperature is connected to the output of the engine - it will reach a maximum pressure governed by the header tank cap. The pressure from the pump is about the same as this pressure so that governs the pressure leaving the head. The thermostat is the biggest restriction in the system so the pressure entering the head is lower

TGP has moved the thermostat so that its on the output of the head in an attempt to increase the pressure in the head. It will do this, but as the header tank will not heat up until the thermostat opens, the background pressure will increase more slowly. As flow through the header tank also goes through the heaters etc TGPs engine will heat up faster, but his heaters will take longer to come on. TGPs theory is that once the system has stabilised, the head is at the pressure at the output of the pump, or background pressure plus a bit. On a standard bongo its at the input to the pump, or background pressure minus a bit. The extra pressure should help cooling.

TGP, have I got your idea right?

Personally, although I can see the logic, I'm not sure it should be necessary. As we don't know the ins and outs of the system I'd worry about it too. For example, where does the turbo gets its cooling? If its the water from the header tank then this will be restricted until the engine is hot, this could be counter productive.

I think the bongo design is basically very robust, it will operate reasonably well even with a clogged radiator, and defective fans but under these conditions reliability is reduced. With a 10year+ old car though these symptoms are common, and add that to 10+ year old rubber hoses and an engine temperature guage which tell lies and we have the basis of the bongo cooling system weakpoint.

Dave

Grahame at work wrote:Experiment 1 update

I had to join a ½ mile slow moving queue this morning on the way to work. This gave me plenty of time to watch the temperature readings.
When ever I was not moving the top hose and expansion tank hose temperatures were the same, when moving the top hose was always higher.
As I approached the end of the queue the Mason gauge was showing 12 o’clock / 50% and the hose temperatures were just over 60. The bottom hose was reading just above 20.
As soon as I got going (actually managed to reach 30mph ) both readings dropped, down to about 40 and 30 but the Mason gauge rose steadily to the running position of around 70%.

Conclusion

I need to protect the sensors from air flow.

However I think that I shall get similar readings on each and that will be around 60-65 most of the time. So I don’t think it is going to tell us much.

I really want to position them so that I can tell when the stat is open/closed or in a ‘balanced’ ½ way position so that I can see if things are approaching the pending disaster state. That is to monitor the ‘input’ and ‘output’ conditions of the cooling system as a whole, if the input temperature approaches that of the output then zero cooling = panic.

Regards Grahame

Grahame, you seemed to have doubts about your fan operating. If the fan operates properly you may not reach the disaster state.

I've convinced myself that it makes sense for the hot coolant to go straight to the header tank - this will pressurise the system in the fastest time.

Dave

Still working on a '2 dimensional' graphic - a question - where does the conventional theory say the fed TO the heaters come from? is there an 'output' from the block that is hidden in the 3 dimensional sketch we are currently using? - if so how high up the block is it?
I understand that the 'return' is on top of the stat - am I correct?

Aethelric - yes I have my concerns about the fans but its more to do with releability of operation than not at all. They do come on but I'm not convinced that its when I expect them to.

Regards Grahame

Grahame at work wrote:Still working on a '2 dimensional' graphic - a question - where does the conventional theory say the fed TO the heaters come from? is there an 'output' from the block that is hidden in the 3 dimensional sketch we are currently using? - if so how high up the block is it?
I understand that the 'return' is on top of the stat - am I correct?

Aethelric - yes I have my concerns about the fans but its more to do with releability of operation than not at all. They do come on but I'm not convinced that its when I expect them to.

Regards Grahame

Not sure we have a conventional theory! I think its the output from the header tank. The return on the top of the stat would make sense. It would give a flow through the system even with the thermostat closed.

With the thermostat closed though, we still have flow in the bottom hose so there is some sort of a bypass. Does anyone know where the turbo gets it cooling from?

Dave

Don't forget there is a bypass around the thermostat housing in the return , even if the thermostat here was removed and replaced with a thermostat in the cylinder head outlet pipe then you will still get the coolant circulating around the crankcase and cylinder head.

For heater coolant inlet & returns goto:-

http://www.lushprojects.com/bongoparts/ ... nents.html

For any other diagrams look at:-

http://www.lushprojects.com/bongoparts/pages/

Experimented tonight with the pressure tester on the expansion tank and the pressure never exceeded 11psi and that was with the fans on and the (Mason) temp gauge showing around 1 o'clock.
It took around 10 minutes of revving at 3000 rpm in a 20 deg.C workshop to achieve that.

I'm now wondering about the importance of the water pump. On a conventional cooling system the pump primarily takes the coolant UP from the lower radiator tank to the engine block. It produces little pressure for circulating the coolant - that's left up to convection currents to raise the coolant up to the thermostat and out to the radiator top tank.

NOT so in the Bongo system..................the water pump cannot lift the coolant from the bottom radiator tank until the stat has opened and as the thermostat bypass is above the water pump then what is the pump actually doing in bypass mode?

I might be talking through my arse here (nothing new TGP cries ) but as the system heated up when taking the pressure readings it SEEMED that the metal pipe from the thermostat got hotter before the radiator bottom tank

Keep up the good work.....................

dandywarhol wrote:Experimented tonight with the pressure tester on the expansion tank and the pressure never exceeded 11psi and that was with the fans on and the (Mason) temp gauge showing around 1 o'clock.
It took around 10 minutes of revving at 3000 rpm in a 20 deg.C workshop to achieve that.

I'm now wondering about the importance of the water pump. On a conventional cooling system the pump primarily takes the coolant UP from the lower radiator tank to the engine block. It produces little pressure for circulating the coolant - that's left up to convection currents to raise the coolant up to the thermostat and out to the radiator top tank.

NOT so in the Bongo system..................the water pump cannot lift the coolant from the bottom radiator tank until the stat has opened and as the thermostat bypass is above the water pump then what is the pump actually doing in bypass mode?

I might be talking through my arse here (nothing new TGP cries ) but as the system heated up when taking the pressure readings it SEEMED that the metal pipe from the thermostat got hotter before the radiator bottom tank

Keep up the good work.....................

I believe the bongo pump pushes the water out of the head towards the radiator. It all goes into the rad and comes out via the bottom hose and the other top hose to the header tank (and hence to the heaters). So its pushing water around the heating system continuously. It is also pushing water through the rad continously, as we have deduced there is a bleed around the thermostat somehow (maybe via the turbo??). This flow through the rad increases when the stat opens. The pump is crucial. - See my earlier post.

Dave

Aethelric - I don't agree about the flow through the radiator before the stat opens unless you mean through the hose connections at the top [ Dandy is what you are calling the top radiator tank?].

As per the sketch referenced by Dipstick the flow either to or from the heaters is out of the block at 'Z' (somewhere above the starter?) to both front and rear heater and back through 'Y' to the top of the stat housing [Dandy is this the pipe you refere to?] so there is always flow through the heaters irrespective of the stat condition (including TGP's system).
The turbo is connected to the outlet/inlet of the cylinder head (just above the alternator) and to the top of the stat housing - so it also has flow irrespective of the stat condition.

So is the coolant coming out of the head and into the block at the stat housing (not very far) or the other way round?

Regards Grahame

Grahame at work wrote:Aethelric - I don't agree about the flow through the radiator before the stat opens unless you mean through the hose connections at the top [ Dandy is what you are calling the top radiator tank?].

As per the sketch referenced by Dipstick the flow either to or from the heaters is out of the block at 'Z' (somewhere above the starter?) to both front and rear heater and back through 'Y' to the top of the stat housing [Dandy is this the pipe you refere to?] so there is always flow through the heaters irrespective of the stat condition (including TGP's system).
The turbo is connected to the outlet/inlet of the cylinder head (just above the alternator) and to the top of the stat housing - so it also has flow irrespective of the stat condition.

So is the coolant coming out of the head and into the block at the stat housing (not very far) or the other way round?

Regards Grahame

Hi Grahame
I think there is flow through the radiator before the stat opens because the bottom hose starts to heat up straight away (albeit slowly), as soon as the engine is running, and before the thermostat could have reached its opening temperature of 82C. If it were dependent on the stat, the bottom hose would stay completely cold and heat up quickly when the stat opened.
I did think that there may be a partial use of the radiator between the two top hoses, bit your measurements disproved this. There in negligible temperature difference between the top hoses.
Flow through the turbo was a guess - seemed a good idea. Cooler water from the rad always feeding the turbo!

Dave

My understanding is the heat transfer convects/pumps out of the head at the driver's side and along the metal pipe to the radiator top header tank (not expansion tank) and circulates back to the head and stat bypass via the expansion/degassing/whatever-you-want-to-call-it tank.

It also circulates in the heater and turbo system at the same time.
When the engine requires extra cooling the thermostat opens by heat conduction through the thermostat "block" attached to the head and now allows the flow to circulate through the expanse of the radiator. When this happens the bypass circuit is closed off and all coolant circulation takes place through the radiator until the temperature drops enough to close the stat again and reopen the bypass. The coolant cannot flow in the radiator circuit until the stat opens. A certain amount of heat can conduct through the hot radiator and lower pipe but it won't circulate until the stat opens. When I felt the hoses tonight during warmup it seemed that the large bore metal pipe to the radiator was hotter than the bottom radiator tank and core. That's why I believe the stat is opened predominately by heat at the engine side, not the radiator.

I don't believe there's anything flawed in the system, I think the problems arising come from neglect/bad maintenance. If there is any blame in the design it is that the return 'stat system means that the radiator isn't circulating as much as it could in a conventional setup - and could clog up. but that's still a maintenance issue in my book, flushing/changing antifreeze by the book would alleviate clogging up of the core.

The waxstat type of thermostat is flawed by design in so far as it can (and often does) fail CLOSED causing overheating. Manufacturers raised the operating temperature of their systems to make the engine more efficient and raised the opening point of the stat to do so. This puts more stress on an already flawed product.
Designing the stat to be in the return side makes it work less hard and I presume more reliable (operates at a lower temperature).

If the position of the stat was causing heads to crack then all Bongo heads would crack - simply NOT the case - I still put the problems suffered by an unfortunate few down to blocked and partially blocked systems putting undue stress on the engine components when they're needed most.

I have to admit I haven't read all this thread, but the bits I have seen seem to mostly confirm what we suspected before.

Is there anything that contradicts the basic flows shown on this diagram that I drew ages ago? (click on the image to get a full-size version)


I am pretty sure the connections are right because I looked very hard at all the diagrams from the stuff I assembled on lushprojects.com. I also checked against what I could see on my car.

I don't think the heater system is directly linked to the header tank circuit.

I can't cope with all these words. Must Have Pictures

Thats how I see it working alpha - the only comment I'd make is that the red/blue might confuse people to think there's a hot/cold thing going on in the diagram. It could be shaded bright red from the head outlet and fading slightly to dark red as it cools

alphabetter the small blue pipe from the header tank if I remember correctly goes to a metal pipe at the front of my engine that I took to be the front heater pipework.

This is where the heater take off is on the engine.