[QUOTE=Daim;1593019]Electrical water pumps can be turned on and off to tweak fuel economy... BMW use it frequently on their active dynamics system. It saves the engine having to use power (and therefore fuel) to always pump it through. QUOTE]
I think it also has a whole lot to do with cheapness of manufacture, assembly and componentry, Daim.
Greg

 

[QUOTE=Greg in France;1593363]That as well. But mainly fuel economy. A belt/chain driven pump is always dragon on the engine. Cause more friction and more fuel consumption... Dich that and you free up some power and use less fuel. Like electrical power steering, electrical air con compressors etc.

 

I put an electric water pump in my '87 V12 a year or two ago. There is ample room for one inside the left front wheel well (see photo, it's not of the finished installation but pretty much looks the same). I have +1 tires on mine, and even with those there is ample clearance.

I also ditched the engine driven fan and aux fan, and put in a pair of dual electric fans. Got rid of the coolant crossover pipe and thermostats and put four temperature sensors in the coolant manifold piping (you can see the brass fittings where the temp sensors were installed) so I could monitor coolant temps at four locations.

Some of the malcontents on the forum heartily criticized this project, which took a lot of fun out of posting. In any case, it's doable, it's your car, so do what you want with it and enjoy the experience.

John
1987 XJ-S V12

 

Good for you. If you have the time, could you post a little more about how you control the temps each side with the electric pump in the absence of thermostats? I have managed to do away with the radtop bleed system, crosspipe spout (not the pipe) and find room near the bulkhead to install a "normal" higher-than-rad expansion tank. Works wonderfully too. So I am most interested in what you have done.
Greg

 

Very interesting John, I will join Greg with the questions. So I assume all you did with the new electric water pump (EWP) is plumb it from the lower rad hose opening to the EWP in the left wheel well to the stock belt driven water pump using the "old" lower rad rubber hose & it looks like PVC Sch 40 for plumbing material. I never thought to locate the EWP there.
Your four sensor's in the water rail housings. What will you connect them to in the cabin to complete the monitoring system ?
Thanks for the post, looking forward for more on this Jaguar.

 

.

nice work , that should take care of the dreaded V12 overheat worries!

are you going to use a digital temp gage, with a 4 position switch, sounds doable,yeah.

most of the guys on this site have not experianced the V12 dropped valve seat issue, and they just say ,if factory system is in good condition,never any problem!

maybe so but 75/80% of V12 went down because of overheat issues!!

 

I have this diagram.
When ignition is on, the engine is running, all work like stock. The E-pump is disabled, the vacuum can be to the heater valve.
When ignition is off and T-switch is on E-fan & E-pump works together, the vacuum isn't run to the heater valve.
The E-pump and non return valves is from XKR.
When the weather is very hot the temperature drops to approx 80C within 5-10 minutes. The T-clock is a little up 1/4.
But there is one little weakness. When the weather is very cold the engine a little bit longer to warm. Because the coolant run bypass thermostat .

 

question; the E-pump is from an Jaguar XKR, and what does it do on XKR?

 

XKR has two pumps. One is for climate control MJA6710AA or MNA6710AB (small one).
One is for supercharger intercooler C2C1314 Comparison sizes. There is different brands.
(little bigger).
Non return valve MNC6742AC

 

The worry will forever remain. We've been conditioned


Which is generally true.



True enough. But there's overheating and then there's overheating!


I'll take this opportunity to beat my usual dead horse....

A lot of time is spent worrying coolant temperature when coolant *flow* is equally or, quite possibly, more important. More specifically, no air pockets. Valve seats don't drop because the coolant was 210ºF instead of 190ºF. They drop because the surrounding area became super-heated due to lack of coolant in the area.

Bleed, bleed, bleed the system. If unsure of result, bleed again.

All the modifications in the world, including after-cooling, won't save your valve seats if coolant isn't reaching all areas of the cylinder head.

OTOH, if coolant is reaching all areas of the head you're not likely to drop a seat, even if the coolant temp is higher than we'd like....within reason of course.

All the above is "IMO". To be taken on a for "whatever it's worth" basis

Cheers
DD

 

doug, use of EVANS coolant can not boil and cause the localized hot spots to occur!

Evans along with a GOOD E-pump ,plus some changes in the coolant flow in the block and heads, 2 large E fans, and i'm betting overheat and dropped seats ,will /should relieve any worries of V12 cooling problems.

jaguar V12 engines never were designed with an effecient cooling block and head system.

personally i think the V12 should have a cooling pump on each cylinder bank(2 pumps).

 

I believe Doug is speaking about cooling systems that are partially empty, leaving air pockets in the worst possible places. Evans coolant, in addition to being the worst thing around for heat transfer efficiency, will not fix a system that's low on coolant or improperly bled.

 

mikey, the factory pump is barely able to pump coolant thru,because the block and heads have to many nooks and crannies that slow moving coolant cant flush thru!

like said a GOOD high flow ,high pressure E-PUMP would push coolant thru and fill the pockets, without even having to start the engine, you could even put some small bleed valves in known places , mostly at the rear of the block/heads!

along with good oil coolers, and a lower thermostats settings, i have run 180F on most all my engines for 60 yrs, and i have nevver actually worn and engine out from low temps, yes ,i know emissions, and that dont amount to a hill of beans!

 

That's part of it, yes.

But, also, over the years I've become fairly convinced that a great many V12 cooling systems are opened up and not properly bled.

Cheers
DD

 

In lieu of the engine driven water pump I just put a blank out plate with a 90 degree bend so a hose can from from the water pump into the block. The pump and pump controller were from Davis Craig. The unit comes with a control box that, depending on what temperature you want, will increase the coolant flow rate and then turn on the electric fans if necessary. This system will also run several minutes after engine shutdown to help remove residual heat from the block. I've not had a problem with it running down the battery.

The PVC pipe show in that photo is part of my "cold air induction" system (air filters are in the headlight housings), so it's not related to the cooling system.

My original intention in installing the four temperature sensors in the cooling manifolds was to investigate the possibility that the "rear" ran hotter than the "front"...I'd read that somewhere but never saw any evidence of it myself. Their second purpose was so I could monitor the performance of the Davis Craig controller and see if it were actually doing its job properly, and it was. The third reason was to see how much it helps to raise the bonnet after engine shutdown...not for the sake of dropping a valve seat as much as extending the life of the fuel injector harness and other wiring I recently rebuilt. Needless to say I suppose, opening the bonnet lets the block (or at least the wiring above it and the bonnet liner cool much more quickly, hopefully extending their lives. Obviously I don't do that everywhere, just at home.

Given that the Davis Craig unit seemed to be doing what I wanted it to do, I've since removed the manifold temperature sensors since had turned into triple redundancy. The Davis Craig unit has a temperature scale, and of course the stock gauge still works, so i have two independent methods of watching the water temperature.

The attached photos show the blanking plate (where the stock water pump use to be) and the 90 degree bend. the hose goes through a hole in the fender out to the water pump.

Also shown are the location of the temperature sensor (on the coolant hose just behind the radiator) as well as the cold air intake duct). There is also a pic of the controller (and yes, the inside of the door is off because the left door won't open from the outside and I'm scratching my head on trying to fix that...posts on here talk about it but I don't see how to reach it), and an overall view of the engine bay.

Thanks,

John
1987 XJ-S V12

 

i like it, if that DC product was around 1995 it would be on car now!!

i could change ,but i'm always monitoring with digital gage and dash gage!

doug is right , seeing at the daytona races the best of the XJ-XJS and Grp44 cars go down for overheat problems , along with reading reports ,puts a scare into you.

 

As foolishly installed by Jaguar the injector harness is actually *clamped onto the engine* in the middle of the Vee.

If you relocated your harness out of the Vee.....most reposition it to run alongside the fuel rail....you've already taken THE most significant step in preserving the wires, IMO


Cheers
DD

 

So, in the following arrangement I'm trying to address a lot of potential issues with an EWP mod.

Redundant pumps
Allows for variable temperature operation on the fly depending on intention ( power vs economy )
Deliver low temp coolant directly to the heads
Produce zero noise on startup
Reduce coolant flow restrictions
Increase coolant flow
Reduce both coolant and under-hood temperatures after shutdown

Critique or improvements would be appreciated. If you feel the need to say "Its fine as it is!" go right ahead.




Redundant EWP setup

 

You did ask for critique

-Redundant pumps

Is there a known problem with pump reliability?

-Allows for variable temperature operation on the fly depending on intention ( power vs economy )

The thermostat will negate variable temp operation. Expecting a noticeable difference in power and economy according to coolant temp is unrealistic.

-Deliver low temp coolant directly to the heads

Not sure why this is required or is even a good idea.

-Produce zero noise on startup

How and who cares?

-Reduce coolant flow restrictions

What restrictions, and do they presently cause problems?

-Increase coolant flow

Why, what are the benefits?

-Reduce both coolant and under-hood temperatures after shutdown

As discussed above, the problem is engine externals and accessories being exposed to excessive heat over a very long period of time (decades) . Pumps and fans to drop coolants temps will do little to reduce the temps in the critical areas, and might make it worse.

 

Great project, but your lovely diagram is a bit confusing for the OEM accustomed! The blue (which I take to be the cooled flow from the rad bottom) looks more like where (OEM) the hot water is. OEM, the heated water exiting the head goes into the rail on the outside of the heads and once the stats are open, along the rail into the thermostat housing and thence to the radiator. If the stats are closed the crosspipe sends it back to the water pump and straight back to the heads.
If you intend to do away with the crosspipe between the two sides of the V and the thermostats, then surely the two pumps should be one for each bank of the V and be controlled independently? If you intend to do it, I feel it might be a big mistake to reverse the coolant flow in the heads; so assuming you do not want to do this, the cool flow exiting the rad needs to go into the "emptied out" OEM pump chamber, and either be divided into two by a vane of some sort or be left to do it on its own, or if using two pumps have each pump connected directly to a bank but still using the OEM entry point each side of the pump chamber.
Also why not keep the heater supply hose where it is OEM at the back of the A bank rear water manifold, for far simpler plumbing?
To really simplify the system, make it far more reliable and easy to service, doing away with the radtop bleed pipe, banjo bleeder, fill spout and all sorts of small pipes, while making the system far more intuitive is easily possible on your model if non-ABS. Add a wizard rad and you will have cracked it, without all the electrics and grief your major rework will entail.
Having said all the that, the OEM system with two decent electric fans and a wizard rad will do the business, no bother!
Greg