3.9/4.0 V8 Transplant Cooling System

[Bowie69]

Not sure about the valve in all honesty, especially if a cheapo one - if it fails, what happens? 

The fans on the front of the rad are for the aircon, aren't they? 

... And yes of course I have chopped up a thermostat, when one fails shut in the middle of winter what do you do?

[Phill S]

Posts must have crossed!

For those now confused I deleted a chunk on my last posting to do with fiddling with the by-pass circuit. A penny dropped and I need to take some more measurements today, will rehash later today...

[AlWorms]

1 hour ago, Phill S said:

Yeah - you're not a weirdo or anything 😉

Haha. Yeah, right! I TOTALLY am one!

I like your thinking. I'm in Clinical Engineering in the public health sector (medical equipment servicing), so it's a bit like aviation, but not organised! I have Aspergers and ADHD, so sometimes I need to be told the STFU, because I don't get what's going on - so feel free!

I REALLY like your thinking. I've not long been into the Rover V8 - I brought this disco for a fun toy, because it was really cheap. I have built a VW Touran, with a Golf R32 drivetrain (3.2 VR6, manual and 4wd, + 7 seats) for mini me's and family trips.

I'm not too bad at solving problems that don't exist 😁

It would actually be brilliant to design a system where the pump output went into the block, circulating well throughout, then through the heater and the return is directly aimed at the thermostat wax pellet, but on the INLET side - much like Subaru used in the EJ motors (and many other brands use, too), so the block stays consistent temps.

I also fitted an EJ25 to my '84 transporter, so modified the system to work in that van. Incorporating the thermostat plate that forces full radiator flow once the thermostat is wide open would be awesome too. I think the block design is all wrong for it though! Maybe we could cast our own 😁

Also had some BMWs... so German cooling systems are something ive had to battle learn the function of.

What is your main reasoning for not wanting flow to the heater core all the time?

[Phill S]

Ok - anybody reading this thread might be a little confused at this point, but I realised I'd taken a measurement in the wrong place, Many a long year since all those lectures on flow through pipes that I never used in practice, but it's all in there somewhere. So here's the rehashed version with Q&A at the end for those that got there before the big edit yesterday:

--------------------------------------------------------------------------------------

Now, you might think I'm a bit OCD when it comes to concerns about overheating, but... Now retired I spent my working life in R&D aircraft flight control systems design and flight test. Not to trivialise it, but get things wrong and bad stuff happens - witness the Boeing 747 Max angle of attack debacle as just one unfortunate example. I'm afraid the ingrained habits of a working life don't go away when I turn my attention to the RV8. The cooling system being a simple closed-loop  control system means I'm going to want to take a good look at that, fully understand how it works, what are the worst possible failure cases, where the accountants came in and said "make it cheaper", and whether there might be any scope for improvement with a little guile and a little money. And then there's the combined knowledge and experience of you guys - there's no substitute for that.

Soooo..... 

My next steps in thinking about the cooling system. Giving it a jolly good looking at yesterday and with June and El Niño just around the corner I'm going to shelve the heater fit until the autumn and simply send the heater feed straight back to the pump inlet - it's basically what happens anyway, just via the heater - at least as far as it was on my donor Disco as it came out of the factory. Here's a thought to be going on with though. The Disco is a big ole internal volume and will need a fair amount of oomph to heat that volume. On a hot summers day wherever you are on the planet, that hot coolant is just being routed through the heater matrix unused, and directly back to the pump inlet. That's actually quite a bit of hot coolant just going round in circles...

 

Now. I'll almost certainly be using the electric fans from the donor Disco:

 

Assuming they'll fit in the bodywork. If not, I know Mr Fridge has a solution. I'll have a play with the viscous fan as well for good measure. I'll need a temperature switch - standard Disco 1 one is 100⁰C. Might want to go lower. Then a thought occurred - bear with...

If we use the thermostat housing outlet as the datum, this is 30mm diameter which gives an area of 707mm² . The heater pipes measure up at 16.5mm bore diameter or 214mm² area. You can see where this is going. Somebody will have done this before.

If we assume flow losses through the heater circuit and radiator circuit are reasonably small, as a rough estimate, at the point where the electric fans switch on I'm still dumping around 20% of the hot coolant straight out of the intake manifold back to the pump inlet, because as designed the bypass circuit is always active. And I'm only putting 80% through the radiator. You may tell me I'm worrying unnecessarily, but I think I want that 20% going through my nice fat radiator under this condition. Being at the point where the fans have triggered, the thermostat will be (should be) open by a goodly amount. So all I need is a valve that will close the bypass circuit when the fans are running. I should perhaps say running from the temperature switch, not just because the air conditioning is on. That could be messy.

I have a cheapo valve left over from another project like this:

 

This one is normally closed but they also come normally open, which would obviously be what we need here. Thinking about getting a cheapo one of that sort and seeing how it works out...

 

Whaddayareckon?

================================================================

Having thought about it some more I will probably hold off doing this until winter time when I do the heating/cooling, and that will give me direct experience of how the standard system works as a baseline. Although of course, I could just disconnect the wires to compare. Hmmmm.....

 

Q&A time!

22 hours ago, Bowie69 said:

Not sure about the valve in all honesty, especially if a cheapo one - if it fails, what happens? 

Cheapo one as a prototyping step. If it's worthwhile look for a better model. As a normally open unit, electrical failure is (should be!) fail safe. You'd have to chop one up and look at the guts of the thing. Alternatively it could jam closed, but it's all brass moving parts so unless you've got a lot of carp in your cooling system.... But then you've got bigger problems elsewhere.

 

22 hours ago, Bowie69 said:

The fans on the front of the rad are for the aircon, aren't they? 

Yup - and with the Davies Craig 150 pump config on my initial lashed up first engine run, they seemed to be doing an ok job. Somebody must have tried using Disco/RR aircon fans before?

 

22 hours ago, Bowie69 said:

And yes of course I have chopped up a thermostat, when one fails shut in the middle of winter what do you do?

Rush about wringing hands?

 

21 hours ago, AlWorms said:

I like your thinking

Please communicate your opinion to the woman in my life...

 

21 hours ago, AlWorms said:

I have Aspergers

I subscribe to the view that "The World Needs People With Asperger’s Syndrome", although I'm not keen on the term "normal":

https://www.dana.org/article/the-world-needs-people-with-aspergers-syndrome/

 

21 hours ago, AlWorms said:

sometimes I need to be told the STFU

Nah - give it all you've got

Sounds like you're busy with a whole lot of projects! Not sure that I'd want to mess with the internals of the RV8 in that way myself though - I need to get this truck on the road asap!

 

21 hours ago, AlWorms said:

What is your main reasoning for not wanting flow to the heater core all the time?

Aah - that's to do with how I think I want to implement the heating/aircon. My wintertime project. Along with the new paint job. And the suspension overhaul. And the and the and the........

A good question for @TSD  though!

[Bowie69]

41 minutes ago, Phill S said:

Somebody must have tried using Disco/RR aircon fans before?

They have, consensus is they are not up to the job. 

[TSD]

1 hour ago, Phill S said:

23 hours ago, AlWorms said:

What is your main reasoning for not wanting flow to the heater core all the time?

Aah - that's to do with how I think I want to implement the heating/aircon. My wintertime project. Along with the new paint job. And the suspension overhaul. And the and the and the........

A good question for @TSD  though!

Ibex has no bulkhead vents panels and the windows are sliding panels like a Series, so there limited cool air into the cabin. Neither of mine has a shutoff flap in the heater box (by design) so even with the diverter set to cold, the airflow still gets some small amount of warming from the heater core. Shutting off the heater core is just one more experiment.

[FridgeFreezer]

2 hours ago, Phill S said:

Now. I'll almost certainly be using the electric fans from the donor Disco:

2 hours ago, Phill S said:

Yup - and with the Davies Craig 150 pump config on my initial lashed up first engine run, they seemed to be doing an ok job. Somebody must have tried using Disco/RR aircon fans before?

A friend of mine did many moons ago in his V8 Range Rover and quickly discovered that they are there only to supplement the ruddy great viscous fan on the engine and help waft a bit extra through the aircon condensor when it's working hard and not moving very fast.

You can see in the design of them they're visibly different to OEM electric engine cooling fans.

If you want a contrast to my ambulance's cooling system, my 109 (also 4.6, also written up in the members vehicles section) has no heater core oil cooler, just a very open-core radiator & two old Saab fans & the Freelander relay under control of the Megasquirt ECU. The heater ports on the engine are blocked off. That truck is built to be as simple as possible, as it was built to get into & out of nasty places and keep going / be very repairable.

A long time ago I looked at the DC water pumps but was put off by their short quoted lifespan and the fact it's another thing to plumb & wire & control. I actually bought one cheap at Sodbury many moons ago and it sits in the expedition spares box as a universal "get out of jail free" card for any truck in a group, no matter what engine, to be able to limp home if a pump or something else fails.

 

As it happens because I'm intending to fit the Freelander setup properly to the ambulance soon I've revised and corrected my write-up: https://fuddymuckers.co.uk/wiki/doku.php?id=alfie:electric_fans

[smallfry]

Your credentials are impeccable Mr Bond  Phill.

But the circulating water in the heater offers an opportunity for extra, or emergency cooling.

You can put the blower on and have all the windows open if necessary. A bit uncomfortable in the height of summer or the Sahara, but sometimes needs must, and all that.

[FridgeFreezer]

6 hours ago, Phill S said:

And I'm only putting 80% through the radiator.

Just coming back to this - I think the heater circuit in total is likely a lot more restrictive than the main radiator circuit.

[Phill S]

16 hours ago, smallfry said:

Your credentials are impeccable Mr Bond  Phill

Aaw gedoutahere. Was just wanting to say I was taking an engineering design approach to this and not just being a dog with a bone. However:

16 hours ago, smallfry said:

You can put the blower on and have all the windows open if necessary. A bit uncomfortable in the height of summer or the Sahara, but sometimes needs must, and all that.

Yeah - I've had to do that before now. Old banger with fixed mechanical fan, summer, A30, holiday traffic jam. Need I say more...

 

20 hours ago, TSD said:

Shutting off the heater core is just one more experiment

Cool 😉

 

21 hours ago, Bowie69 said:

They have, consensus is they are not up to the job

Getting that message fast. But it's all been done before and I will certainly be going through:

20 hours ago, FridgeFreezer said:

If you want a contrast to my ambulance's cooling system, my 109 (also 4.6, also written up in the members vehicles section)

And thanks for the pointer to the muddystuff, I will be going through all of that...

As a minor digression:

20 hours ago, FridgeFreezer said:

A long time ago I looked at the DC water pumps but was put off by their short quoted lifespan and the fact it's another thing to plumb & wire & control

I use a Davies Craig pump on the ex-army RV8 I showed earlier because the car it went into had a lot of space issues under the bonnet. Works fine, but the pump I used in my 3.9 engine run up was one that I had decided had done enough time and put back on the shelf as an emergency spare. I wouldn't use one on the 110 because it would seem to me to over-complicate what I need, but for anyone thinking about it, they need to live in the bottom hose area and there's a big old lump of metal in the way called the steering box. That would make the plumbing very messy. And I certainly wouldn't want to hang one on a plastic radiator.

 

16 hours ago, FridgeFreezer said:

I think the heater circuit in total is likely a lot more restrictive than the main radiator circuit.

I think you're right. Don't tell anybody I did this, but if you blow through the heater matrix and then blow through the radiator you can get confirmation of that. Just for the record that was the Disco 1 heater. So it looks like if you're content to permanently plumb the heater to receive hot coolant all the time it's not that big of a deal, but if you want to use the H-type valve to return the coolant direct to the pump inlet, you might be loosing cooling effect from the radiator?

Hoping to be on the road in about a month, that will be without a heater box and just connecting the in/out pipes together, so I'm sort of drifting towards taking an experimental look at including an electric valve in the bypass circuit in the way I've been wittering about. Unless anybody can tell me it's a bad idea?

[smallfry]

3 hours ago, Phill S said:

 

Yeah - I've had to do that before now. Old banger with fixed mechanical fan, summer, A30, holiday traffic jam. Need I say more...

 

 

Been there, done that in an Opel Manta I had back in Eighties. I stupidly took the fan off to wring some extra power from the engine, like you do.

Got caught in central London with some friends. It was in the Summer and hot. Had to have the windows down and heater on full blast. It was dragging in the traffic fumes and dust (no pollen filters back then) and was sweaty and most unpleasant.

When we eventually got home, it looked like we had gone blackface !

Remember the A30 thing from when I was a kid and we were off to Devon and Cornwall. It was a regular feature of the holiday ISTR. Happy days though !

[Phill S]

Happy days indeed. How did we ever survive before health and safety were invented.

Possibly my last question on the wet bits before I go into deep thought mode on heater valves, fans, and general plumbing arrangements. Those two pipes at the air intake:

 

I understand that the inlet manifold needs an air bleed, they took away the one on the carb apex. The workshop manual is vague and just really says they're there and they're hot. What's their purpose? Anti-icing in cold conditions?

[Bowie69]

Yes, anti icing, however.... You can remove it from the circuit if you want with little effects, at least in this country. 

If you unbolt the plate they attach to and plug the two holes that aren't blind it means you can remove the passenger rocker cover without unbolting the plenum....  Which can be handy. 

[Phill S]

Great - and thanks for the tips. Don't think I'm going to use the intake heating thing then. I'll put it on the under review list.

Planning to use the original brass expansion tank, assuming it's big enough? The Disco 1 one is massive (and plastic) and I'm beginning to get a bit picky about space in the engine bay...

[smallfry]

I would think it will be fine. I don't think you have increased the coolant volume by any significant amount. 

If you are concerned, maybe do not fill it quite so much when the system is cold. As long as there is some in there it will be fine IMO

I'm sure an educated gentleman with your background will know by how much the coolant will expand when heated ! 

[FridgeFreezer]

12 hours ago, Phill S said:

Planning to use the original brass expansion tank, assuming it's big enough? The Disco 1 one is massive (and plastic) and I'm beginning to get a bit picky about space in the engine bay...

I only use brass tanks - they are more robust and can be repaired in the field, unlike the plastic ones that get brittle and love to split.

[Phill S]

7 hours ago, FridgeFreezer said:

unlike the plastic ones that get brittle and love to split

Bummer - original brass it is then. Thanks to all for all the help and advice on this one. I'm away for a time now, parts are on order so I can hopefully get rolling when I get back

[Phill S]

Ok - so I learn that there are different ways of achieving a water cooled engine:

 

And I'm very interested in the two-stage electric fan concept:

https://fuddymuckers.co.uk/wiki/doku.php?id=alfie:electric_fans

 

But just before I start to think more deeply about electric fans, I have this great big propeller option:

 

So what are the pro's and cons of those?

[Bowie69]

Massive pain when working on the fro t of the engine, will use a bit more fuel, and are noisy, especially on start up. 

They do shift serious amounts of air and great when in the Sahara, but not really needed over here, a good OEM electric fan will more than cover you. 

[hurbie]

46 minutes ago, Phill S said:

So what are the pro's and cons of those?

the pro is , you mount it , and then you can forget about it 😉 

[ThreePointFive]

On 6/3/2023 at 10:37 PM, FridgeFreezer said:

I only use brass tanks - they are more robust and can be repaired in the field, unlike the plastic ones that get brittle and love to split.

Or aluminium, for cheaper than the "new" old stock on eBay. Still robbery, but less robbery. 

[FridgeFreezer]

15 hours ago, hurbie said:

the pro is , you mount it , and then you can forget about it 😉 

That's the theory, yes.

However, without wanting to ignite an internet holy war on the subject, there are some real-world cons to them.

• Right pain when reaching into the engine bay for maintenance, especially with the engine running
• Require a matched cowling to be effective which can be difficult to get right on a conversion
• Always spinning - Always ready to catch & eat whatever comes by, I've seen engine-driven fans lose blades and/or eat radiators due to debris, wading, or just bearing failure pitching it into the back of the rad.
• Harder to replace if they break

With the trips my 109 was designed for and the approach of brutal functionality that Jez brought to every decision building the cars I prefer electric (ideally twin electric) for maximum survivability.

• If one fan fails, there's another one right there (very very rarely do both fans need to be on)
• I can hear the fan kick in & out and I've got a warning light that tells me one or both are on (or should be on).
  • Bonus: Gauge & fan are two different sensors, so I have a redundant way of determining if things are OK. Gauge says OK but fans are running? Something's not right.
• I can have a switch or move a wire to force the fan to run all the time if there's a cooling problem
• If my fan(s) fail I can take almost any other electric fan from any parts place, scrapyard, etc. and cable-tie it in place and be running again.
• If my fan hits debris or something bad it may well just pop the fuse rather than destroy itself or my radiator. Since it is usually not turning, crud caught in the fan will likely just sit there and pop the fuse on startup.
• I've got a clear foot of access space between engine & rad that's not taken up by cowling or whirling blades

This is not to say engine-driven fans are BAD and electrics are The Only True Way^TM, just that there are always compromises. Engine-driven fans are undoubtedly a reasonable solution in many ways or the manufacturers would not have fitted them. Obviously they require no wiring or sensors/switches and can move lots of air.

There's also potentially an issue on some engines (notably TDi) where the rapid thermal cycling of a big electric fan kicking in & out has been hinted at as a cause for head gasket failure as the cast iron block and aluminium head expand & contract at different rates and (in theory) stress the head gasket. However, the Rover V8 is all-aluminium so that should not be an issue.

Anecdotally, I've seen far more viscous failures than electric, but then someone else will undoubtedly post that they've seen many electric ones fail while they've never seen a viscous fail.

[Phill S]

Thank you! That's a very helpful and comprehensive treatment. Gives me the eebie jeebies thinking about getting up close and personal with the fan when I need to get the timing properly set up.

Having said that I'm going to fit the viscous fan, mostly because I'm in a hurry to get the machine MoT'd and time is going by. Aiming to take it to southern Italy this autumn via Corsica and Sardinia as a first foray, lots to do by way of internal fit, and there'll be a whole lot of worms that coming wriggling out once I start driving it after this engine fit. Want to get some UK miles on the clock this summer to build confidence.

The front body will all be coming off again this winter for re-painting and at that point I'll be going electric fans.

 

[Phill S]

Finally back on project! A massive amount of time spent reconfiguring a Disco 1 wiring loom for my '87 110, life events, and a requirement to go on holiday. Sadly, the 110 not yet ready for action, so 6 weeks in the old L200.

Along the way I bought a little something in Turin:

 

"What's in the box Phill?" I hear you cry.

A new old stock brass NTC6168 that's what...

 

Weighs a ton compared with the Britpart plastic one. 

So it looks the part, but anybody able to shed any light on who the manufacturer might be? Came in a plain brown box. The only identification is a fairly primitive stamping on the top surface:

 

Anybody able to shed any light? I assume it was manufactured in June 2007?

[Paul C]

If you are going to use the viscous fan, the cowling is basically a disco1 cowling which has been cut out for the narrower piping.  I will have to find the pictures if you need them.