I have one of the “smog” intake manifold cars that has all sorts of secondary stuff (I have removed the butterflies and blanked off the secondary fuel routing with brass tubing etc…)- if I re/de-route the coolant, capping off nipple at WP, and the like will this then create “hot spots” in the manifold at the head such that I should just plumb as factory and not worry? If it is any factor, I plan on pulling the heater core box out of the circuit as I really never use it in my climate and the cockpit runs warm, as is (that and I feel that the original box is a weak link in the system, due to its age- I ran demo demolition derby as a kid and learned early to take off-line the heater core as I was sprayed with hot coolant when it gave way, luckily we had replaced the glycol with water and I was wearing enough to keep me form being scalded).
Huff, if you want to take the heater components out of circuit you can make some plugs to fit inside the hoses where they enter the bulkhead, under the carbs. That way you get zero hot water anywhere in the heater system and everything looks stock.
Huff, I doubt that you reduce induction temperatures by routing the coolant away from the intake manifold. The manifold is well attached to the head which is hotter than the coolant. Also you might develop hot spots in the head if the flow in an area is reduced.
I like having the heater core as an secondary radiator. If the coolant gets too hot, turn on the heat & fan. The E-type has the added ability to dump that heat out the bottom of the heater box instead of sending it to the passengers.
I really didn’t think I could sidestep the game of thermo-dynamics and reduce manifold temp, much. I like the idea of having the heater core as a “backup radiator” as well, but I worry about the old girl so I will do what I have done before is dead-head the two line to themselves (a “U”) at the aft end of the manifold and cap off the heater core (after putting some coolant in there to slow down the rot). At one time I had a shut-off valve in line to try to exclude the heater core, somewhat, but there is still flow if one cuts off one line and one can’t put in two shutoffs lest there be no flow through the manifold.
Huff
On my seriesII jnstalled 2 shut off valves to stop coolant flow to pipes and heater box. This has worked well to reduce cabin temps. I also block off all air flow from heater box by using some magnetic sign material to cover screen. My A/C works much better with this setup. Coming back from the BSOL yesterday I had not yet turned off valves and put cover over screen. Going through Vegas interior was hotter than usual. With valves closed and screen blocked I can push both levers to the on position (in). In the on position the flap on bottom of heater box is also closed preventing air flow from there at speed. Covering screen is only a good idea if you have A/C.
That’s something I hadn’t thought of, I had always thought that we had to suffer along with it! But your right, it would just dump it out the bottom, cool! Or maybe not
Cheers,
LLynn
Surely, when the heater valve (the water valve) is turned to off, there’s
no more water flowing so you have “stagnant” water in the manifold, no?
If this is the case then either one has to keep the water valve open to
ensure a flow of coolant to keep the manifold “cool” in which case good
luck to to trying to keep the cabin cooler in the summer, or it makes no
real difference if the water flow to and from said manifold is cut off, or
not.
As mentioned in an earlier reply to this post, I have simply plugged the
hoses at the bulkhead on the carb side. No water flowing through the
system at all.
Tom,
So if it’s required for good running, shutting off hot water flow via any
means is a bad thing, right?
I can’t recall the actual flow routing but it seem like water flows through
the manifold, into the heater tubes, around the heater and back out to the
pump, or the reversal of that.
If the aforementioned is correct, just shutting off the heater valve will
presumably stop water flow across the manifold, and either the manifold
will get hotter or it will get cooler, which if it’s required for fuel
vaporization, cool is bad.
I’m referring to my setup with two Strom’s and the extra manifold of
course, although I have removed the exhaust heater bridge across the engine
and plugged the outlets to the heater pipes…the flow might be
different with the earlier triple SU’s and one less manifold, but I
wouldn’t think so.
As Tom pointed out, running coolant through the intake manifold is done to help vaporization of the fuel, primarily to help get the engine off choke quicker after a cold start. It is completely benign from a performance and driveability standpoint, so kinda silly to try to defeat it.
I wouldn’t think heating the intake would be as much of a concern on the jag 6 but definitely agree that it is there too heat, not cool. on other inline 6 engines with down draft carbs, their are more bends and greater distance and can be an issue. this link explains it a little better http://www.langdonsstovebolt.com/tech/why-you-need-to-heat-your-intake-manifold/
jrinam, good article. My understanding is it can be a problem on any engine, and is not only for warming up from cold but under many conditions. Lack of heat can be extremely hard to diagnose, as many people do not understand how much the fuel creates cooling, both from the heat required for vaporization as well has the cooling from the Venturi effect, and thus never even think it could be a problem. In some cases, they even remove the heat source thinking they are making their engines perform better. They never even think that it may be their drivability problem.
Tom
Ok, understood but doesn’t that mean it is always flowing through the
manifold and comment please on my assumption that if the water valve at the
heater is turned off, doesn’t that stop the water flowing through the
manifold, seeing as that’s where the hot water comes from?
As I had stated earlier I had installed two shut off valves controlling flow to heater.
Believe that is all that is shut off. One valve is between firewall and manifold and the other on line from water pump to firewall. Don’t fully understand the flow and maybe only one valve is necessary? This is a latter seriesII. My original thought was to have the ability to stop water flow if water pipes in firewall should fail. What I learned is that shutting off flow reduced heat in cabin and increased the performance of A/C.
Les, I am surprised that the heater would shut off the manifold flow. But since I am not near my car I cannot confirm or deny, but it is not what i believe is typical . If it does shut it off, maybe they felt it was only needed when it was cold enough for heat. But again that would surprise me to depend on that.
Tom
Les, I have not found a good schematic, so I could be corrected… My understanding is the coolant enters the intake manifold from the head. From there it can go to the thermostat (if open to the radiator), the bypass to the water pump, or to the heater. The return from the heater goes to the pump. From the pump to the block, and then the head. Hope this is correct & helps.
Glenn, I have done exactly what you have done except I used plugs in those
hoses so that the car “looks” the same as it would if all was connected and
running as designed. My reasons of course are the same as others…to
prevent heat getting into the cabin from unused heater or pipes.
I installed new pipes during the refurbishment (still underway) so that if
the heater is required at some point (not in Georgia whee I live) the plugs
can be removed and the pipes are stainless so wouldn’t be a problem.
A good schematic would probably answer my questions about the routing of
the water flow during normal operation.
Either your car is very different from mine, or your explanation contains some misunderstandings, or I misunderstood your explanation. On my car (also a Series 2 with a secondary throttle housing assembly between the carbs and the intake manifold), there are no water ways in the secondary throttle housing. All the water ways are in the intake manifold directly attached to the cylinder head. Hot water enters the manifold from the head through holes in the gasket that attaches the head to the manifold. The channels in the manifold heat the manifold. There are two ways for the water to exit the intake manifold. At the front, the water can exit through the thermostat to the radiator, or if the thermostat is closed it will take the bypass hose directly to the intake of the water pump. At the back of the intake manifold is a pipe nipple from which a hose connects to the heater via the pipes behind the firewall. The return from the heater also takes a pipe behind the firewall, and emerges into a hose which connects to a hard pipe hung under the intake manifold with a second hose at the front that connects to the intake side of the water pump. So, the main radiator and the heater are effectively in parallel in the circuit. Shutting the heater valve has no impact on the flow through the intake manifold - it just only has one way out (through the thermostat), rather than two.
