Since system bleeding is my hot button, here's a question......

Would it make sense to provide multiple bleed points?

Cheers
DD

 

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doug thread #33 addresses that idea!

 

Potential issues versus actual problems can present a dilemma. Different people approach the dilemma differently.

There's a lot of satisfaction in designing an executing a plan such as what you've proposed, and I have full appreciation of that. Sometimes, I think, the satisfaction derived from performing such modifications is greater than the need of doing them.

Ages and ages ago I designed an e-fan set-up for my XJ6: two fans, two speeds each, three (or was it four?) modes of operation. Lots of fun working out the details. It worked exactly as designed....but in reality was over-the-top and provided no real world benefit over an earlier, vastly more simplified e-fan configuration.....which in itself never provided as much improvement as I was looking for.

Later...this is really silly so it's OK to laugh.... I somehow became convinced that I was having a fuel drain back problem and that a fuel system primer would be the cat's meow. A pressurized fuel rail before I even got my key into the ignition! I used a GM "entry timer" and some relays to rig up a system that ran the fuel pump for 10 seconds whenever the driver's door was opened....tied into the inertia switch and with a defeat switch, etc. It worked exactly as planned.....but the problem I was trying to solve turned out to be more in my head than grounded in reality.

Not a criticism, just food for thought.

Cheers
DD

 

Yes, but with the e-pumps you are assuming that the increased flow is filling the voids. Maybe so, but.....

If you had multiple bleed points you could verify, or at least be more confident, that no air pockets existed.....with or without the e-pumps.

Cheers
DD

 

No. Experience proves that increased flow will not always bleed 100% of air out of the system.

 

Thanks for the comments and opinions guys! I probably should have better described things up front, but there's no time like the present!

This arrangement reverses coolant flow in the block. From radiator into the water rails out the front inlets. This should evenly cool all 6 ( adding support for the center two.) coolant ports without the balancing restrictions of the Lutz mod.

It has no crossover pipe because it has no bypass system. coolant flows from rad to pump to rails out the old inlets into old pump cavity out blanking plate pipe to pump 2 to radiator.

This systems doesn't use thermostats at all. The controller varies flow from the pumps to control temperature. It meters temperature at the junction at the old water pump location. If maximum pumping does not meet the target temperature then it activates the efans.

If I was going to maintain the current flow direction this would be a good routing.

I have other versions of this system. One does have the pumps one per side. While I liked the concept of treating this like two independent i6 engines, I thought that the same hardware, in this configuration, would offer a more significant benefit by offering redundancy.

That's cooled coolant from the radiator in my diagram. Not the best source for the heater coil.

I even think the OEM system with the OEM rad and OEM mech/e fans is sufficient.

This system is unnecessary. But so are V12s. So?



All hardware fails. This system has a two-stage failure mode. That's better than a one-stage failure mode.

There are no thermostats in the diagram. It meets the pre-set temperature target through varying the amount of flow and activating the efans.

And physics says there is a difference in power and economy based on engine operating temp. Noticeable? Yes. Important? I don't know, if I want to drive to Vegas then yeah.

The purpose is to better control the flow into all of the coolant ports on the rail and there by ensure even cooling of the heads. And delivering coolant to the head first rather than the block is intended to deliver the coolant to the hottest components first better equalizing temperature differentials throughout the engine.

Evans don't run until actually needed in this setup, and I care!

Oh how I hate the roar of that stupid mech fan uselessly sucking cold air through the cold radiator for no reason. I would rather hear the engine quietly idling all by itself. Now, this could be accomplished just by replacing the mech fan with an efan. I'm just itemizing things I like about this whole setup.

Thermostats for one, and I don't know. I assume not. I didn't suggest they do.

Greater total heat dissipation capacity. Greater total heat generation capacity.

Dropping the block temperature slightly more rapidly and properly circulating air under the hood after shutdown will not harm my engine.

Nor will it prevent heat exposure to all the items under the hood. It's going to get hot under there.


Somehow I managed to upload a version without flow arrows. So bad. Like I was trying to make you solve a puzzle. Sorry, here.

 

Indeed. But here I am enjoying the design process and solving problems involved in my solution.

I'm not about to go pulling hoses and tossing them over my shoulder. But I am working on a long term plan to clean out the engine bay. This is just one planned mod.

Of course, I'm always re-evaluating my plans and sorting the list of things-to-do. If this one fails muster then it will join the others in the stack of things I once thought were a good idea.

 

See comments inserted

 

Thanks JigJag for all the explanation. I totally agree with you and Doug about doing things for the fun of it. Following your explanations, I have two further points that I think are worthwhile considering carefully:
1) I truly believe reversing the coolant flow is a bad idea. OEM, the cooled flow enters the heads and swirls along round all the liners etc etc and "naturally" exits the top of the heads as it warms up through quite small orifices. The Lutz mod takes care of ensuring enough flow to the rear of the engine. Your setup is trying to force water downwards through these orifices, having pushed it along smallish pipes, and then it has to force the coolant downwards and out of the engine, as it heats up, at a lower level than it entered. I feel this will just about guarantee steam hotspots, poor water jacket filling, and air in the system which cannot easily escape as it needs to escape against the coolant flow. In fact precisely equivalent to reversing the flow in a radiator by feeding hot coolant into the bottom if it.
2) The worst aspect of the XJS V12 installation (which is NOT duplicated in the XJ40 or X300 application of the same engine) is the radtop bleed arrangement and the siting of the expansion tank. AFAICS your mods do not address that aspect. I think this is a major opportunity for a very substantial improvement and simplification wasted. All the XJS bleed problems and quite a few others, are caused by this aspect of the layout, and all the counter-intuitive installation pipework complexity. As for extra bleed points, assuming OEM flow direction, it just needs a vent fitting in the heater valve supply pipe. Having said that, whenever paranoia has struck and I have eased that pipe off to check for air bubbles, there have not been any!
Great project, once the idea has been refined, and great fun. In my own case, I would only caution that the only mods I have ever made that have let me down, and in 100% of cases, is the installation of any device containing modern electronics!
Greg

 

Interesting.


1. Ford used the two "cooling" system layout from 1932 til 1953. A lower and top hose for each bank. One water pump for each. One radiator, although one version used two cores. The 32-36 cars used WP's at the front of each head to lift the water up and into the radiator. The later cars used a WP on each bank at the lower hose.
Pumping cooled water in to the block. Some of the cars cooled just fine, others not at all???


The later cars enjoyed huge radiators???


2. My LT1 features reverse cooling. Touted by GM as allowing better cooling throughout the engine. It seems to work just fine.


Carl

 

Reverse cooling can and does work great on engines that were designed for it from the ground up. Backyard conversions carry a huge risk factor and seem pointless when there's no problem with the status quo.

 

so reverse flow... switch the radiator so the hot is in the back and the cool in the front so it gets fresh cool air not heated air that passed through the first half of the radiator...
I agree!
I might want the two pumps not in series but Parallel, one for each bank.. with temp sensors for each head and will that controller handle two pumps independently ...
if not two controllers


I like it! it would/will work just fine the way you have it.... if ever you want to go crazy and use an aftermarket ECU controller to run on one bank and shut the other down for economy I would do two in Parallel

 

JJ
Just FYI, as shown in your second diagram, on the XJS there is no OEM water manifold serving the middle two cylinders of each bank - I have heard that there was in the V12 pre HE E Type installation but I am not sure.
Greg

 

You're correct. There is no connection there, but the ports are there. Blanking plates over them.

Your earlier post also mentioned the smallish water rail
As a concern. Valid. Here is the solution for both these issues.

 

The latin gets me.


But, the picture is amazing. Whomever did that is an artist and craftsman....


Carl

 

Want one
​​​​​​​

 

GM did the reverse flow change ,to allow cool water into the cyl. head 1st to reduce chance of detonation,or loose valve seats, it works , and allowed better control of timing! more advance.

why they changed back i donno!

i would prefer an EWP on each bank, just to keep faster flow to each side!

the question now: who gonna do this mod, and see what works, not many Jaguar V12 race cars around anymore?