Electrical Driven Water Pump on a K Series Engine.

[Banjo]

I'm just in the intial phases of fitting an electrically powered water pump, to my 5K Engine, that is sitting on a test bed, in my garage atm, with my trigger wheel project thereon.

I was wondering, if anyone on this forum, has ever done this before; or knows of anyone on here, or, elsewhere on the internet; that has accomplished this mod previously.

I'm currently just figuring out how to create an inlet coolant spout, for the front of the motor.

 

 

 Well, that bit didn't work !  I was hoping to keep it all Corolla, but the top hose spout, points in the wrong direction.

Cheers Banjo

Edited July 6, 2023 by Banjo
adding pictures

[Banjo]

Well, a little bit further advanced on this experiment.

The original water pump backing plate, cut down; is now mounted on the 5K EFI project.

Without the water pump & it's fan belt driven pulley, I have fitted a shorter belt between the crankshaft pulley & the new 120A alternator.

The belt adjustment tension bar, is now pivoted off a post on the upper RH corner of the backing plate; as previously, it was in the same position, but on the front of the pump body, that no longer exists.  There is not a lot of room, betwwen the back of the alternator & the timing chain cover, so the white plastic pipe, was used to work out where an entry point was needed on the backing plate to feed the water into the block's water jacket.

The original hole in the backing plate was filled in, & welded with a filler piece.  A new hole was cut above to be the entry point for coolant to the block water jacket.  The bottom raditor outlet, will be connected to an electric water pump, whose outlet will be connected to the bottom of this depicted 25mm dia. copper pipe.  So here is what it looks like at the moment.

The vertical copper pipe has been left intentionally long; so that when the electric water pump arrives from Sydney (thank you ebay), I can mount it down near the bottom radiator outlet, & then cut the depicted vertical copper pipe to a length, to suit the final position, of the new electric water pump.

The pump I have ordered is a Bosch model, which they claim can move about 2400 litres/Hr. It is a 12 V DC 90W model, which means it will draw around 7.5 amperes, at full speed.  It has an "S" terminal on it, where a frequency controlled pulse voltage can be fed in, with a frequency betweem 9Hz - 110Hz; controlling the pump from zero to full speed.

I am hopefull, that once I have it working, that we can not only optimally control the coolant temperature, but make it more uniform across the block & head.  Standard K Series motors, are known to run hotter on the rear cylinders; particularly no: 4.

Cheers Banjo

 

 

 

 

 

Edited July 13, 2023 by Banjo

[Trufauru]

love to see that people still tinkers with this old engines

[parrot]

Will it somehow still be controlled by the standard thermostat?  I wonder what the flow rate of the normal water pump is.  Possibly may need to enlarge the thermo bypass to minimise turbulance?

[Banjo]

Hi Sebastian,

Quote

love to see that people still tinkers with this old engines 

Yes, it's fun, cheap, & they were a damn good engine design in the first place; confirmed by their longevity.

Once you've got your car body rust all sorted; You too, will have fun, I'm sure, with the mechanical side of things.

Cheers Banjo

Edited July 14, 2023 by Banjo

[Banjo]

Hi Pete,

Quote

Will it somehow still be controlled by the standard thermostat?  I wonder what the flow rate of the normal water pump is.  Possibly may need to enlarge the thermo bypass to minimise turbulance?

With totally variable speed water pump, & complete control over the operation of the radiator fan,  I can see how it should be possible to hold coolant temperature at a fixed temperature, or over a very narrow band; under all driving conditions.

The electric water pump speed, will not be in anyway, controlled by the thermostat.  In fact, I am hoping to remove the thermostat altogether, as both a restriction, & coolant temp controlling device.   My preference would be to control & maintain, the coolant temperature, by electric water pump speed, & therefore, coolant flow rate; based on various inputs, into an intelligent controller.  The electric water pump's on/off & variable speed operation, would be determined by a number of temperature sensors, located at different areas of the engine & block.  I should be able to drill & tap sensors into the Welsh plugs, so I can see what coolant temp differentials are around the block.  Ambient temperature would be an input, as well as whether the cabin heater was being utilised, as well as engine loading & operating characteristics, like TPS, RPM & MAP readings, many of which I can exported from the Speeduino ECU.

The radiator electic fan, will also be on/off controlled by this intelligent controller.

Coolant initial heating; & cool off, after engine stops; should also be a great improvement. 

My initial thoughts are, that during start-up; neither the radiator fan, nor the electric water pump, would run, for some fixed time (eg: say 2-5 mins); timing being based on ambient temperature. After that time, the water pump would run at low speed, so that there is some minimum flow of coolant, so all temp sensors, around the coolant track, can provide meaningful readings, that will  be used for all control actions, thereafter. 

These are all  unknowns at present, but that is the aim of the exercise; to find the best possible solution.

I already have a bypass from the back of the head of my 5K engine, back to the lower side of the existing thermostat. There was always a short rubber hose bypass in the coolant system, between the existing thermostat housing, & the olde mechanical water pump inlet.  I will retain this, but place a cock in it, so I can throttle it off, or even shut it closed, to see what effects it has.

One of the aims & purpose of the exercise, to to reduce, or hopefully remove; the high temps of the coolant at the rear of the head & block, where flows are low, resulting in higher coolant temps.  My tests have shown that the coolant temps around cylinders no: 4, can be 15 deg C higher, than those around cylinder no: 1.  Many off us, who have lost rings or pistons, in our K Series engines, will atest, to it almost always; being cylinder 4 or 3.

Early attemps to improve the coolant flow around cylinders 3 & 4, was the creation of head gaskets, where the coolant flow holes, between block & head, were sealed off, around cylinders 1 & 2; in an effort to force flow to the back of the block; & hence up into the head around cylinders 3 & 4.  This worked to some extent, but also restricted total flow somewhat.  I'm hoping to be able to open up all the coolant passages in the head gasket, between block & head.

 So, I going into this with an open mind, & not having all the answers; but sure that with what I come up with, will be substantially better, than what I have got at present.

Soooo, Fun days coming up !

Cheers Banjo

 

 

Cheers Banjo

 

Edited July 19, 2023 by Banjo

[Banjo]

For those of you interested, here are the specs, of the Bosch electric water pump, which I will receive on Monday.  I'm sure it will do the job.  I had a giggle regarding the spec. for max. lift, of up to 7 metres.  My guess is that the vertical distance from the radiator outlet, to the top of the 5K head would be about 1 metre, so no issues there.

 

 

[Banjo]

Got the pump lashed up on the test bed engine, & it is now going great, but was not without, a few learning curved balls encountered..  That's it; down in the lower LH corner of the pic.

First thing I noticed, was how quiet the electric water pump was. In fact it was so quiet, it was hard to tell, it was running. The exercise today, was just to get it running On/Off, at full speed.  Varibable speed; controlling the flow rate, will have to wait, until I build a suitable controller.

Initially, I could not get the electric water pump, to run for more than a few seconds, before it automatically shut down.  I figured it was sensing that the pump was "dry", & shutting down to protect it.  It did seem however, a very short time, before it shut down.  I have no idea, what sensor it uses, & was not going to pull the pump apart, to find out.  Purging air from the coolant passages, may be a very definite requirement, when first filling the coolant system. 

I learnt a quick lesson, that the pump needs a "flooded inlet", at all times, & that the outlet, must be facing upwards, & be higher than the inlet; so no air gets trapped inside the pump body, at all.

After I repositioned the pump, (as above) it ran without cutting out at all.  I measured the DC amperes, & it was pulling 5.6 amperes.

I haven't done a flow test on it as yet, as I haven't got it flowing through the block as yet. Currently, it is just lashed up, so that it pumps the coolant back to to the radiator header tank.

The main requirement is, that the inlet of the pump, is at least level, or below, the bottom radiator outlet., as above.  The pump is quite small, & will fit down in that area easily, on most vehicles.

However, watching the coolant flow rate, through the top of the radiator, with cap removed; it certainly is flowing faster, than the normal  mechanical pump, at about 2000 RPM.

So next exercise is to feed it through the block & head, without, the thermostat in situ, & see what back pressure that places on the pump. & what the maximum flow rate, that can be achieved.   I'll just collect what it can pump, in a minute; then multiple that by 60, to get the number of litres per hour.

So now I've proved it works, next stage is to remove all the lash-up, & make it permanent, then repeat the exercise, with the coolant passing through the block & head.

After that, it will be time to fit a number of coolant temperature sensors, all around the coolant system, so I can see the temperature gradient, between the top & bottom of the radiator core, & at various points inbetween.

Cheers Banjo

  

 

[Banjo]

I started off this thread, by enquiriing whether they knew anyone on here, or elsewhere; who had done the mechanical to electrical water pump conversion. I've trolled the internet, & there are a couple.

https://www.youtube.com/watch?v=gX2A9rSLAPw&list=RDCMUCqvXGJXKeLCm6zg-JagDdzQ&index=1

https://www.youtube.com/watch?v=wJNqEZQKwpI

https://www.youtube.com/watch?v=SWkCHaAAerM

Admittedly, it's on a Mini engine, but the techniques & requirements are similar.

Here is another commonly available electric water pump, off an early Toyota Prius.  I like the fact, that it has three (3) rubber isolated mounting points, which renders it easily to mount; unlike the Bosch unit, I currently using.

https://www.youtube.com/watch?v=1ojNID2jDz4

 

Cheers Banjo

 

 

Edited July 21, 2023 by Banjo

[Banjo]

Well, another milestone passed in this little experiment today; with the whole system piped up.

I removed the thermostat altogether, so there was no impedance to the water flow, & then filled the system up with water. I then let the pump run, at full speed, with radiator cap removed; so any air bubbles inside the block, could be  removed from the system.  Only took about 30 seconds for all the trapped air bubbles to be removed.  Looking down into the radiator top tank, with the cap removed; indicated the water flow was substantially greater, than the flow with the original "mechanical" water pump.

It seemed funny, watching the water flowing through the system, when the engine was not even running.  This however, will now be possible, when the engine stops on a hot day, & as well as the electric radiator fan running on; so will the water pump.  This should result in both electric fan, & electric water pump, shutting down sooner.

 

 

 

So next job is to build a pulsed speed controller to control the pump, between 12% - 93% capacity. I believe if the PWM speed control signal is removed altogether, then the pump will run at 100% capacity. Then I'll fit several coolant temperature sensors around the coolant system.  I'll then fire the engine up, & experiment with a few different pump & fan control strategies, until it becomes obvious, which provides with the best results.  There will be three (3) phases, to address.  Startup, & getting up to temperature as quickly as possible.  Running under load; & cool-down, after engine has been shut down, after being driven.

Should be a lot of fun, & I'll pass on here, to anyone interested; what those results are.

Cheers Banjo 

Edited August 2, 2023 by Banjo

[Banjo]

I found a DC motor speed controller on ebay, which controls the electric water pump, & flow of the coolant, from a trickle to full on.  It handles a DC load of up to 10 amperes.  With the radiator cap removed, you can clearly see the water flow change as the water pump speed is changed.

It has a knob on it, which will be useful, as I manually try different flows & resultant temperatures, but also can be controlled by a 0-5V DC voltage, ultimately; from a controller, once a control system & program, is determined.

So I started fitting sensors to the coolant system in several spots today.

One on the hose leading to the top of the radiator, which will basically measure the temperature of coolant leaving the engine head, & entering the radiator.

I already have a return line, at the back of the head, which returns hot coolant to the thermostat housing.  I will fit one to that pipework, close to the rear exit from the head.  Another will be fitted at the water pump, which is attached to the lower outlet from the raidator.  This will allow easy delta T across the radiator, by sunbtracting radiator outlet temperature from radiator entry coolant temperature.  The other place, I would like to measure coolant temperature, is inside the block coolant passages. The most convenient way to accomplish that, is to tap a temperature sensor, into a Welsh plug on the side of the block. It's simply a matter of drilling a hole & tapping it, in a Welsh plug, & then replacing an existing one.  That will require the manifolds to be removed, to gain access to the three (3) off Welsh plugs on a K Series engine.

So almost there, & should be soon starting the fun bit; which will be determining times & control program, to get the very best coolant temperature control.

Cheers Banjo

Edited August 21, 2023 by Banjo