Lotus Europa Community
Lotus Europa Forums => Technical Articles and DIY tools and tips => Topic started by: Lotsof 3146 R on Friday,April 17, 2020, 09:57:10 AM
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Lotus Europa twin cam special coming out of twenty years hibernation.
The water pump is seized, but not leaking externally and there is no water in the oil.
Can I fit an electric pump without removing the original?
I be grateful for any feedback or experience.
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I'm thinking of doing the same to my TCS after my engine rebuild. My concern to leaving the original water pump in place is the impediment to flow with the stock impeller in place. Also the seal may not be leaking now but how about further down the road.
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I have found the following information from https://daviescraig.com.au/electric-water-pumps
DISABLING THE MECHANICAL WATER PUMP
Leaving the mechanical water pump in place, install the EWP® into the bottom radiator hose and remove the manufacturer’s thermostat.
You will need to bypass the water pump pulley by installing an appropriate length belt. This method makes for an easy installation.
If running the pump continuously, remove the thermostat and drill two approx. 3mm (1/8") holes in the thermostat plate to allow some coolant circulation. Re-install ensuring that the thermostat housing is clean and a new gasket is used if required.
What is not clear is if this would still apply to a seized water pump; any experience with EWP on the twin cam would be much appreciated.
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I used a EWP pump and controller in my TCS. I removed the water pump belt, and the mechanical pump freewheeled with the EWP water pump flow. I had no issues, except getting all the air out of the system. It was nice with the controller - you could hear it ramping up flow, and starting the fan with temp changes. Also, the controller ran for a few minutes after shutdown to cool the engine a bit. With the impeller frozen, seems that would impede coolant flow greatly.
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Many thanks for letting me know, I have decided that EWP is the way to go and ordered the parts; if I’m lucky it’ll work; if not, it’ll be engine out and mechanical pump removed.
I’ll update in due time
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Every engine driven water pump that I have seen is a centrifugal type. Most have straight vanes, a few have curved. Coolant can flow between the vanes without the impeller running. it does not matter if the pump is seized.
To take out the impeller usually requires pressing off the pulley and taking out the sealed bearing that it is attached to. Then the bearing hole has to be plugged. You might be able to press it off the shaft or break it.
Porsche was clever enough on the Boxster to use a plastic impeller so when the bearing went out it did not take out the engine case.
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So its fitted, the engine has run up to temperature for the first time in perhaps 10 or 20 years and yippy it works!
No leaks, no water in oil or oil in water and the old mechanical pump remains seized solid.
And the engine sounds sweet with good oil pressure.
Early days - I'll post an update once she's back on the road
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Good job. Were did you install the pump?
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Good job. Were did you install the pump?
On the bottom radiator hose. I fitted a new aluminium radiator and fan at the same time.
The standard EWP 80 comes with a one straight and one 90 degree flange. This is not optimal (and I'm not posting photos of this lash-up:-) ) I have a straight flange on order from the UK importer http://www.mawsolutions.com/index.html
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The lower radiator hose seems to be the easiest place to plumb in the EWP. The biggest issue that I've read is the possible loss or reduction in coolant flow for the cabin heater due to the change in differential pressure across the heater core. I'm very curious if you experience this phenomenon. My plan is to plumb mine in at the inlet to the normal inlet to the engine, at the timing chest.
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Quick and easy installation of an electric water pump and associated thermostat
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I love the electric pump idea! The work you have done looks very good. I do have one question though if I look at the diagrams on the water pump website has online the outlet pushes towards the engine and sucks from the radiator, the way you have this installed the opposite is happening. You are sucking from the engine and pushing coolant into the radiator. Can the system flow either way?
Cheers,
Ross
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i fit mine at the radiator.
(https://hosting.photobucket.com/images/nn56/rascott_2008/IMG_3219.JPG?width=1920&height=1080&fit=bounds) (https://app.photobucket.com/u/rascott_2008/p/3b49d28a-3252-44ae-97bc-156ab9f087e8)
the temp control sensor is in the head, the fan control is still in the radiator.
i'm still turning the waterpump, 'cause the alternator is driven by the wp pulley.
hmmm. the pic is bigger than usual. another mystery.
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I love the electric pump idea! The work you have done looks very good. I do have one question though if I look at the diagrams on the water pump website has online the outlet pushes towards the engine and sucks from the radiator, the way you have this installed the opposite is happening. You are sucking from the engine and pushing coolant into the radiator. Can the system flow either way?
Cheers,
Ross
From the way I see it, both installations have flow going in the correct direction, normally coolant from the engine enters the radiator from the bottom hose and goes back to the engine from the top hose. Lotsof has his pump plumbed into the bottom hose sucking from the engine discharging into the radiator. rascott has his pump plumbed into the top hose sucking from the radiator discharging back to the engine.
This is for the twin cam.
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I love the electric pump idea! The work you have done looks very good. I do have one question though if I look at the diagrams on the water pump website has online the outlet pushes towards the engine and sucks from the radiator, the way you have this installed the opposite is happening. You are sucking from the engine and pushing coolant into the radiator. Can the system flow either way?
Cheers,
Ross
From the way I see it, both installations have flow going in the correct direction, normally coolant from the engine enters the radiator from the bottom hose and goes back to the engine from the top hose. Lotsof has his pump plumbed into the bottom hose sucking from the engine discharging into the radiator. rascott has his pump plumbed into the top hose sucking from the radiator discharging back to the engine.
This is for the twin cam.
Almost right, hot coolant is pushed out of the top of the engine into the top of the radiator, the radiator cools the coolant because the opposite of heat rises occurs so cooling lowers, the cooler coolant is then sucked from the bottom of the radiator to the (normally) lowest place in the engine, the water pump inlet, the water pump then pushes the coolant through the engine, through the thermostat / bypass system, through to the top of the radiator starting the cooling process again.
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Looking at the parts manual to shows the thermostat housing connecting via the pipes to the bottom of the radiator.
I thought the flow was from the engine via the thermostat to the radiator. Am I reading the parts manual wrong or misunderstanding something.
Many thanks for any clarity on the correct flow direction.
PS - I’m really happy with the EWP. And control unit. Even if re-building the engine I’d not want to go back to a mechanical pump.
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i am also interested- i read it the same way.
mine is an s-2- just assumed the tc plumbed the same?
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Looking at the parts manual to shows the thermostat housing connecting via the pipes to the bottom of the radiator.
I thought the flow was from the engine via the thermostat to the radiator. Am I reading the parts manual wrong or misunderstanding something.
Many thanks for any clarity on the correct flow direction.
PS - I’m really happy with the EWP. And control unit. Even if re-building the engine I’d not want to go back to a mechanical pump.
From what I can seen you're reading the manual correctly, it does show flow going from the thermostat to the bottom of the radiator then out of the top radiator outlet to the pump. Out of curiosity I checked the paper and pdf copies of my workshop manuals and there's no real guidance so all you have to go on is the parts manual. I've got to be honest and say until this came up I'd never even thought about it, when I repaired my chassis I just followed what was there to start with.
What Chris describes is logical and how the Elan is plumbed, thermostat to top hose, bottom return into the engine pump so you'd expect the Europa to be the same. I suppose it depends if the pump is push or pull ? I've no idea if that matters, I'd have thought the pump pushes cooler water into the engine block but honestly I've no idea.
Equally possible is that there's been an error in the diagram for all these years and no-one has picked it up ! Intriguing whatever the reason, I might even go and see which hose in the front gets warm first !
Brian
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every car in world that uses water / coolant uses the same system, cool coolant in to the bottom of the heat producer (the engine), heat is removed from the engine inc the thermostat at the top, either by pushing the coolant out or pulling the coolant out to the top of the heat dispenser, (the radiator), cooled coolant is then pulled or pushed from the bottom of the heat dispenser back into the bottom of the engine,
believe me I've been doing this mechanicing / engineering job for nearly 50 years now.
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For some reason, the Europa does not appear to follow convention. I just pulled the coolant transfer tubes as part of my engine rebuild from my TCS and the layout is as per the parts manual.
- hot coolant comes out of the thermostat housing into the tube with the long bend (left hole in the chassis looking forward)
- enters the bottom of the radiator
- gets cooled and exits the top of the radiator into the tube (right hole in chassis)
- enters the engine at timing cover to water pump suction.
You can visually follow the layout by following the tubes from inside the access hole in the cabin
As an aside, the coolant transfer tube feeding coolant back to the engine was a bitch to remove. I had to remove the rear chassis cross beam to get enough room to pull it out.
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For some reason, the Europa does not appear to follow convention. I just pulled the coolant transfer tubes as part of my engine rebuild from my TCS and the layout is as per the parts manual.
- hot coolant comes out of the thermostat housing into the tube with the long bend (left hole in the chassis looking forward)
- enters the bottom of the radiator
- gets cooled and exits the top of the radiator into the tube (right hole in chassis)
- enters the engine at timing cover to water pump suction.
You can visually follow the layout by following the tubes from inside the access hole in the cabin
As an aside, the coolant transfer tube feeding coolant back to the engine was a bitch to remove. I had to remove the rear chassis cross beam to get enough room to pull it out.
So it defies the laws of physics that state hot water rises & vice versa
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For some reason, the Europa does not appear to follow convention. I just pulled the coolant transfer tubes as part of my engine rebuild from my TCS and the layout is as per the parts manual.
- hot coolant comes out of the thermostat housing into the tube with the long bend (left hole in the chassis looking forward)
- enters the bottom of the radiator
- gets cooled and exits the top of the radiator into the tube (right hole in chassis)
- enters the engine at timing cover to water pump suction.
You can visually follow the layout by following the tubes from inside the access hole in the cabin
As an aside, the coolant transfer tube feeding coolant back to the engine was a bitch to remove. I had to remove the rear chassis cross beam to get enough room to pull it out.
So it defies the laws of physics that state hot water rises & vice versa
If a system has forced flow, it doesn't matter which way the coolant flows into the radiator. It so happens that the Europa goes against convention. Check it out yourself. The flow path is fairly easy to follow visually by noting which hole the pipes enter the chassis and exit the chassis. As I said earlier, look inside the chassis inspection hole under the center console to follow the pipe run.
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I've just looked at the twin cam parts manual & you are right, the top thermostat housing connection feeds to the bottom of the radiator.
I admit this goes against everything i've been taught & have taught in the last 47 years about making efficient cooling systems.
I'll ask Paul Matty on Monday why they did this when they could have done it the theoretical correct way or I'll ask one of the designers who worked at Hethel from 69 to 74 & again 86 to 93 then again in 96, perhaps he'll know or he might be able to ask Mike Kimberley
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Perhaps one reason could be that it's not a conventional layout with (almost) horizontal steel tubes going the length of the car. More heat will be lost during transmission to the rad than for a conventional system with shorter rubber hose connections. The temperature gradient will still play a part at the radiator itself but perhaps it's not as significant with this design.
Some cars (Elise) have the radiator mounted horizontally with inlet/outlet at the same level so as Grumblebuns says, with a forced flow system, providing your pump capacity is good enough the thermosyphon effect becomes less of an issue.
Brian
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I am not an engineer but I have a little bit of knowledge of heat transfer and fluid flow remembered from my previous professional career. It takes a very specific set of conditions for natural convection or thermosiphon to occur and I can't think of any production car that was designed with any form of thermosiphon assistance as a design factor. When the water pump fails, the engine starts to heat up. If there is any thermosiphon, the mass flow rate and heat rejection from the radiator is too little to overcome the heat produced by the engine still running at road speed.
Looking at the cooling pipe layout in the parts manual, I'm wondering if the bends in the piping in order to be able to install/remove the pipe was what determined the direction of flow to the radiator. The S2 also has flow entering the radiator from the bottom.
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I am led to understand that Henry Ford thought there should be a way to do away with a water pump but finally realized he couldn't.
I have to admit that I have never given the direction of coolant flow a whole lot of thought. So now I am giving it a bit of thought and I'm thinking that most of the heat comes from the head (right?) and it would seem to make sense to provide cooler water to it. Obviously, I'm missing something. Can someone explain what that is?
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I'm not totally sure of the question but if you're asking how the coolant flows through the engine, this is my understanding for the twink:
- cooled coolant comes out of the top of radiator through the transfer tubes into the timing chest cover front nipple
- through the timing chest cover passage into the water pump impeller located in front of #1 cylinder in the engine block cooling passage
- coolant is circulated into the block and up into the head through connecting passages
- hot coolant is discharged out of the thermostat housing back to the radiator bottom inlet.
I'm not sure if that is what you were asking for but makes sense to provide cool coolant from the bottom up.
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There were quite a few thermosyphon-only cars way back, the Austin Seven for one. Water pumps were fitted to higher-output cars, and later to smaller radiators too.
I think the standard Europa radiator is a crossflow design, actually a twin crossflow. Water enters from the lower left, flows to the right, then upward to the top where it flows right to left and out again. There's a baffle between the two halves to keep it flowing the right way.
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I'm not totally sure of the question but if you're asking how the coolant flows through the engine, this is my understanding for the twink:
- cooled coolant comes out of the top of radiator through the transfer tubes into the timing chest cover front nipple
- through the timing chest cover passage into the water pump impeller located in front of #1 cylinder in the engine block cooling passage
- coolant is circulated into the block and up into the head through connecting passages
- hot coolant is discharged out of the thermostat housing back to the radiator bottom inlet.
I'm not sure if that is what you were asking for but makes sense to provide cool coolant from the bottom up.
Yes, I see that is the actual route the coolant takes. My question is: Since the heat in the engine is generated in the head, that seems like the part of the engine we should focus on cooling. So why wouldn't the cooling system be designed so that the coolest water goes there first? Such a design would work backwards from the way it actually works. The cooled water from the radiator would go to the head, down into the block, and out the water pump back to the radiator.
Since that is the opposite of the way it really works, I'm probably missing something pretty fundamental. Maybe the exhaust stroke pushes out enough heat that the block is actually the bigger concern?
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I could ring Richard although I haven't spoken to him in 25 years
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I'd bet he would remember you! If you do call him, I'd be interested in his opinion on the subject.
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My question is: Since the heat in the engine is generated in the head, that seems like the part of the engine we should focus on cooling. So why wouldn't the cooling system be designed so that the coolest water goes there first? Such a design would work backwards from the way it actually works. The cooled water from the radiator would go to the head, down into the block, and out the water pump back to the radiator.
Good question.
Perhaps the thermosiphon effect is merely a design parameter left over from a bygone era?
How potent is the thermosiphon effect?
Is it like the coriolis effect which is relatively minor?
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How potent is the thermosiphon effect?
Is it like the coriolis effect which is relatively minor?
I've limited experience of the system, we used them on mechanical seals and from what I remember they had to be set up correctly, ideally with the reservoir/cooler directly above above the item you were cooling. Also a metre or so height was required, I think that was to get sufficient temperature gradient but I'm not sure.
It does work and folks sell commercial systems, the big advantage is that once set up there's not much to go wrong with them, and (almost) maintenance free was always a good idea on chemical plant !
Given the relative heights of engines/radiators in most cars you might get some movement but I doubt the effect would be good enough for anything with a decent power output. On the Europa the radiator is well below the engine so it doesn't conform to the normal layout you'd expect for such systems. And on the Europa, if the water pump belt goes then the car overheats minutes later so it does need a decent flow rate to work.
Brian
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Well, I'm going to throw in my two cents. ::)
Virtually all engines flowed coolant Up from the block to the head(s) until pretty recently.
Then someone decided that engine temps would be more evenly distributed if the hottest component (head) was cooled first.
I believe Chevy calls this "Reverse flow" and now uses it extensively.
As so many things automotive today this has a lot to do with quicker warm-up for emissions systems.
Also some consideration of complete engine thermal characteristics since so many modern engines use more aluminum and even plastic components than before.
As I recall a double cross-flow radiator is about 40% more efficient for a given size.
So Lotus may have been well ahead of the curve here. :)
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Quick update:
With the increased flow rate the breather pipe to the top of the expansion tank (swirl pot) acts as a venture sucking in air and causing cavitation at the electric water pump.
A simple value, normally closed when running, open to bleed (see photo) is a quick and simple solution
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The flow through the radiator is reversed from normal convention to make the the system less "air-lock-friendly".