Heat is normally a symptom of some engine or combustion malaise. Any discussion on cooling must start with the premise that the reader has ruled out poor timing, too lean an air/fuel mixture, bad coolant, a radiator or cooling system blockage, a faulty water pump, bad combustion, poor lubrication, a lousy rad fan, a malfunctioning sensor, a bad thermostat, an imprudent camshaft selection or "badge" blockage.
Cooling a car generally concentrates on coolant temperatures and secondarily oil temperatures.
The coolant heat is dissipated by its passage through the radiator which is turn cooled by the flow of air that runs through it. As this flow of air greatly increases with speed and idling engine gets hotter than a cruising engine. Systems to deal with a stationary or slowly moving car must compliment the systems used to cool a cruising car.
|WATCHPOINT FOR ORIGINAL PLUS 8s: I have heard and immense amount
of nonsense in this area. :( All engines and their fueling systems
have a temperature range they are meant to run at. Plus 8s came in two
basic versions, Carburetted and EFI. The first run with the lower end
of the range set by their thermostats..82C for carb'ed cars and 88C for
all EFIs. This can be confusing as Morgan often put their rad fan
switches at the bottom of the radiator, where the coolant is coldest
and yet the temperature gauge is installed at the top of the engine,
where the coolant will be its hottest. (I experimented and had rad fan
switches put both at the bottom AND the top of the rad.) The
temperature difference is 4 to 5C. Of course, the temperature reading
is best taken from the top, but one gets used to a chosen placement.
The rad fan switch must be changed to reflect where the switch
placement is. A good way of checking how accurate your gauge is to see
how close to the rad fan switch's range is the gauge. The fan should
come on when the gauge reads about 100C, assuming the rad fan switch is
placed at the bottom of the rad and 96C if the rad fan switch is at the
top. The temperature sender is just to the left of the thermostat
housing if you are standing in front of the car. It should not be
confused with the EFI ECU temperature sender.
All cars must run within their desired engine temperature range. However, owners often swear they have the craziest temperatures given by faulty gauges or, most likely, bad connections at the coolant temperature sender or gauge. Once a year, remove the wire to the sender, clean the blade on the sender, and make sure your fitting is tight and does not wiggle. Running temperature for a an EFI Plus 8s is around 91-98C. If it is under or over that, you have a problem. It could be, as described, merely a bad connection or it could be worse. The later EFI vehicle (like GEMS) can be very sensiitve to lower temperatures, which will eventually force them into limp-home mode, requiring a computer reset in a world where such systems have not been installed by Land Rover for more than 22 years, which is older than many of the LR dealers mechanics!
Morgan cowls restrict the possibility of large radiators. The louvres do not improve the airflow much and must be considered decorative. The flow of air is funneled through the grill or from under the car. This being the case, the following aids may help when moving.
2. Install an air "dam" or rubber mat deflector underneath the car to force the cool low air (the lower the air from the ground the cooler it will be) up into and around the radiator.
3. Even better than 2. install an air scoop that will funnel large amounts of cool low air into the front of the radiator. A scoop can double the air flow into the rad. There is a Morganesque version designed by Maurice Owen and Bill Fink that replaces the original scuttle (the piece at the bottom of the grill cowl attached to the wings) with a new scuttle shaped "S" funnel that forces the air up from under the car and into the rad. It is remarkable how well these scoops can work. They are available from Isis Imports in San francisco or from the Morgan Factory.
4. Avoid "badge blockage" which occurs when our affection for badges on a badge bar and badges on the grill create a significant blockage of the free flow of air through the grill to the rad.
5. Be careful of your placement of your license plate...if you are unfortunate enough to live in a jurisdiction where front license plates are required try to place it to the side rather than the center of the car if possible. A central placement of the license plate blocks the flow of air under the radiator and makes an air scoop impossible and prejudices even a simple air deflector.
WHEN MOVING SLOWLY OR STATIONARY
When moving slowly or when stationary the radiator does not have enough speed induced air flow to cool well. If these conditions continue, the car will overheat. The solution is to artificially create an airflow when needed with a fan. Obviously, the higher the power of the fan the more the airflow and the greater the cooling ability you will have when needed. Morgan fans are not famous for power but many good replacements are available. (see SPAL)
1. Do not install a fan mounted in front of the radiator. They are an easy install and inexpensive but they create the problem they are supposed to resolve. They block the airflow to the rad which contributes to the overheating and then they come on in effort to cool the rad to the point where they can stop and block the airflow again.
2. Install the fan to operate on a radiator thermoswitch (if you don't already have one installed). This item switches the fan on at a certain temperature and off at a lower one. You can also install an manual switch override that forces the fan on regardless of coolant temperature to deal with a heating situation before it develops fully. Check with your supplier if you require a larger relay switch for the fan you purchase.
3. Remember that all rear mounted rad fans PULL air through the radiator. If you see your fan pushing the air back towards the radiator then simply reverse the wire leads to the fan and recheck the rotation.
IN ALL CONDITIONS
A BETTER RADIATOR.
Morgans are sporting old radiators, some as old as forty years. Their engines do not function as they once did, greater friction than originally is the rule and their radiators are no longer up to the original state of the engine let alone today's state. A better radiator improves cooling whether stationary or moving, but what is a better radiator? Here are some answers;
1. You have had your original radiator re-cored or you have had the coolant flow system of the radiator and the cooling facade and fins renewed. The rad returns (hopefully) to its original cooling abilities. The drawback here is whether the original cooling capacity of the radiator is sufficient for the present state of the engine. You have ignored the benefits of technological progress in the last forty years and you have used the old rad as a base which may be less than a solid foundation.
2. You have purchased a radiator larger capacity than the original though it is conventionally designed. The only drawback here is the technological one noted above and any loss of space considerations.
3. You have had an technologically advanced core installed to replace the original. A good option..but at this point why not go all the way?
4. The ultimate...a high tech aluminum radiator. See An Aluminum Radiator for Your Morgan.
COATING YOUR MANIFOLDS
For some time, there has been an option increasingly offered of coating your manifolds or heddars with a ceramic based compound that very much lowers the heat of this part of your exhaust system..a prime radiator of heat. Essentially the compound..in a choice of colors or effects, is sprayed on your clean sandblasted manifolds and then baked. It is inexpensive and aethetically very good looking, replacing the rust that all Morgan manifolds arrive with even when new. It does not discolor as does stainless steel (which doesn't lower heat).
Make sure that the INSIDE of the manifold is coated..this is more important than the aesthetics of the outside. There are a number of companies in the field and some can be found in the GoMoG General Parts Directory . Be careful of some of the better known firms which coat their products in bulk lots of many customers at a time, leaving a orange-peel effect to the finish.
Curiously, I have only found one coating service in the UK or Europe..though they are common now in North America, New Zealand, Australia, and Japan.
N.B. Please ignore the claims of massive horsepower increases. These are largely pipe-dreaming fancies...though a cooler engine can produce more power and leaves more room for "tweaking" than one which is already running hot.
Wrapping your Headers (NO!!)
Many people still use heat wraps to lower their engine bay temperatures. Essentially, these are a wrap insulation which must be tediously wrapped around each exhaust branch. It is considered by many to be unsightly and will very much accelerate the rusting of the manifolds. They also, of course, do not improve the inner surface of the manifolds and thusly do not speed the flow of gases. They can, however, block the heat from the wrapped section.
Coating vs Wrapping
I get asked this question quite often, and there’s really no easy answer since each application is different, and everyone has a different budget. But in a nutshell, ceramic coating is the better option.
There are two issues when using a wrap that do not come into play when using a ceramic coating. These issues are thermal fatigue and moisture corrosion.
Wraps decrease under hood and under wing temperatures and because of that save other components. But they also shorten the life of your exhaust. Wrapping promotes thermal fatigue of the component you wrapped. It is a type of metal fatigue caused by repeated heating and cooling, also called creep damage which leads to premature component failure. Some owners believe that wraps help prevent thermal fatigue, but in fact, it is the opposite.
Wrap your headers and a few years later, there are holes in the piping. This can happen quicker than you might think.
Moisture is the second issue with exhaust wrapping. The wrap will actually pull moisture in and keep it there, holding it against the component, which speeds up the corrosion process. Ceramic coatings are self-sacrificial in design, meaning that they will corrode/rust/oxidize before the substrate underneath will. It’s a good idea to go with a coating company that offers a warranty, be careful of companies that only cover 'rust-through', meaning that there has to be a hole in your exhaust before it will get covered!
Coating the Exhaust
The best option to manage heat is to have your exhaust ceramic coated. The coating actually bonds to the substrate (at about 10,000 psi) and prevents the heat from soaking into the substrate. If you get it done right, the rate of expansion of the coating will match that of the substrate, or the metal your manifold is made of. Your exhaust component can usually be coated on the inside as well, giving it thermal and corrosion protection inside and outside.
It’s also a good idea to go with a company that creates/manufactures their own coatings, not one that just buys it from an online coatings store and slaps it on. There's a lot more to the application/preparation than you would think, and if a company has the resources to manufacture their own coatings, odds are they’ve been in the game a long time and have the processes to near perfection. The downside to ceramic coatings is of course the cost. You can get enough wrap to do most of your exhaust for around $50-$100, compared to a full system getting coated for around $500. You get what you pay for.
Top quality ceramic coatings can reduce engine bay temps by over 50%, and the more common cer-met or ceramic-metallic coatings can reduce temperatures from 30%-40%. Another added benefit is that you will see power gains anywhere from 3-5% by keeping the exhaust gas velocity up. Increase spool-time in a turbo system, and increased scavenging is another benefit of the increased exhaust gas velocity.
So, when the time comes to do some heat management, do some research for yourself, look at your budget, and determine which direction is best for you. If you can only afford the wrap at that point in time, get it so you don’t cook the rest of your components in your engine bay, just keep in mind that it’s a “quick fix” and get your components coated when you come into a bit of cash.The Thermostat (NO!!!)
|WATCHPOINT Carb'ed engines often run at a lower temperature range than their EFI counterparts. This is why they are less fuel efficient. For example, the Plus 8 runs a thermostats with an opening temperature of 82C with carbs but 88C with EFI.|
|STANT (Thermostat Manufacturer)|
|many more available on request|
all but a few of us, Morgan body aerodynamics is a iffy area to go into
for the obvious reasons of the aesthetic prejudices caused. Morgans
sell and are beloved for what they look like, making deep changes in
this area heretical for a car that has a sillouette protected by a
European body patent.