by Lorne Goldman

As with so many things, cabin heaters were a straightforward component until the 1990s. There are so simple that I have often mused at the reason why Morgan did not simply design their own cabin heater systems rather than running to less-than-ideal systems through their cabin climate years! They certainly had the capability of doing so as they personally made me an earlier Smiths plenum when it was needed for them to rebuild my Morgan in 2002.

The First Smiths Cabin Heaters 
The first cabin heaters were optional and remained so until 1969/70. They were called fug stirrers. It was a Smiths Industry item made for the early Land Rovers
. It consisted of a small matrix (a "matrix " is a name given to the little radiator core used to heat air for the passenger cabin) and fan, both placed atop the bulkhead in the engine compartment. compartment. in the engine compartment. Availability: Parts for this system have become extremely hard to find or replace. Be patient and look on or .ie. I have also seen the cores at Europarts and Holden.

The Later Smiths System (1970-1985)

The system was used by Morgan for many years.  It's best virtues are its simplicity and compact size..which make it easy to modify/improve without crowding out space used for other components or requiring much labor...(the curse of the later Morgan Classic cabin climate systems). After 1974, two air outlets were added to the front which feed the then-new demister vents air conduits.

Two coolant hoses
from the hotter (aka front upper) section of the engine are run to, through and from its heater matrix (effectively a small radiator (223 x 190 x 53mm) that sits on the bulkhead.  An air plenum (either the tatty looking original or a prettier aftermarket affair) slips tightly over the matrix and funnels air from the bonnet slats through the heated matrix and then through a hole in the bulkhead into a small  heater box in the occupant cabin which also encloses the heater fan. There are two air conduits that sprout from the front of that box and feed the demister vents at the windscreen. At each side of the cabin heater box are flaps which allow airflow to the passenger and driver areas.  The design splits the needed space between the bulkhead (plenum and matrix) and the cabin (heater box with fan and flaps) and therefore allows more space in both areas.

The fan, a rather feeble one, (potential solution for that) functions at two speeds through the use of a resister (looks like a coiled spring) attached to the rear of the cabin 
heater box. This resister lowers the voltage of the motor which responds by turning at a slower speed. Morgan used a choke cable to awkwardly close and open a mechanical valve on the bulkhead to control the flow of hot coolant through the matrix.  However, in practice, you will continue to get hot air unless you block the air from the bulkhead plenum in some fashion. As well, ideally, the two hoses will have a bypass valve before (engine side) of the mechanical valve which allows the coolant to keep circulating when the valve is shut,

Availability: As of the date of this article, all parts for the later Smiths system is still available from British car specialists or on ebay. (December 2017). Addiaionally, when the later system appeared, many British owners had this system swapped out for the next one...(a BIG mistake!) and some of the older dealers still have the unit in their old stores.

WATCHPOINT: The most common things that go wrong:
1. Morgan has used a very awkward shut off valve for decades. It is cable operated and the necessary twists and turns required, arrive at the thingie which is installed weridly to work at all. Yet without a shut off valve, (a less-than-brilliant cost saving for the 1990s cars) the cabin is constantly hot as the cabin heater matrix is constantly hot. Of course, even without the heater fan on, the rush of air pushes the hot air into the system, the matrix and into the cabin. (sad sigh)  I can think of two solutions. My friend Lance tapes a plate to block air inflow into the heater on the bulkhead. Or try the one I describe below. Works a treat!
2. Your matrix has not been flushed for too long and is partially block or gone south,
3. Your cabin heater flaps are closed.
4. Your hoses to the windscreen demisters have dislodged. Easy to check and sort.
5. Your cabin heater fan has slipped its connections.

Post-Smith (1985-1987)

The cabin heater used after the last Smiths was one of the sadder examples. Morgan management has always been extremely cost conscious..which often develops into a penny-wise-pound-foolish tendency which thrives more now than the past. In this case, they chose the last of a failing company (see the current sadness
with circuit boards and LR column). Those that charged with component supply, base their purchase decisions on price, rather than the more important priorities of suitability, durability and the assurance of continued supply. This cabin heater is another example. It functions poorly, it takes up too much space and the supplier quickly went bankrupt elminating the supply of repair parts from 1988 on.

It consists of a long box on the bulkhead again having the matrix covered by its plenum. The fan motor is also placed on the bulkhead crowding the area. Yet its bulky heater box is, of course, behind the dash in the cockpit, eliminating precious space there as well. I have mogged with this system for a few thousand miles.and  I have nothing good to say about. I recommend it be replaced before it fails you.

Availability: None

Peck (1987-1993)

After the bankruptcy of the above-noted supplier, Morgan was forced to find another. These were sourced, at the time,  from a company called "Peck"  who made
a matrix/fan in a box, with 12v or 24v options which were often used for pleasure water craft. Peck was taken over by a company called (click)  Gallay and then made at a new factory they set up in Wellingborough, UK where they still manufacture today.  Sadly, this unit was even LARGER than the system it replaced, eliminating even more of the behind dash space.
Availability: Check with the company at the link given.

K L (1993-1997)

Morgan changed yet again for a period from 1993 to 1997 to a still existing company called K L, a division of which is again supplying them with airconditioning unit currently.


by Lorne Goldman

Decades ago, in the early 1950s, Morgan began offering cabin-heating and windscreen-demisters as an option. That was still in the era where the Morgan factory designed and fashion most things inhouse and mechanical expertise was very high. They immediately realized that a shut-off valve was necessary for the system, not merely turning off the forced air (the cabin fan) but also the heat source of the hot coolant flowing through the cabin heater matrix (aka the little radiator) that sits under the cabin air plenum on the bulkhead. They fitted a cable-operated shutoff valve on the bulkhead. The valve is/was an awkward affair made for anything but the use it was put to here..but it worked..a bit. The cable is run through a tortuous routing making it stubborn and binding..but coming from the era of choke cables and clutch cables and many others, it was understandable. and the theory for its necessity eminently logical.

As they did not wish the hoses running over the hot engine to continue to unnecessarily heat the coolant in the hoses going to and coming from the cabin heater, they placed a bypass between the two lines. Therefore, when the valve shuts the flow to the matrix, the hot coolant keepts circulating.

Of course, over the years, these awkward valves break, bind, and cause much cursing. Owners have fit them with better designed valves that operate by hand directly, or ones that better respond to a cable. And then, oddly, just when they were needed most, they disappeared, an eliminated component. There is no logic to this, but the Morgan Factory no longer functions as it did during the Morgan Golden Age. See Editorial.

Without a hot coolant flow shutoff valve to stop the feed to a hot matrix (cabin radiator) perched atop the cockpit, the cockpit can never be properly cooled.  It is not merely a matter of shutting of the air flow...radiant heat produces heat as well. Imagine a home heated by water-filled radiators. Now imagine the effect on a hot day if the hot water flow to the radiators cannot be stopped!!!! But there are other causes the curing of which willl VASTLY mitigate cabin heat problems.

by Lorne Goldman

It is also easy matter to eliminate the awkward and unhappy cable-operated used by earlier Morgans (pre-1999) by substituting an inexpensive ($25-40) electrical solenoid shut-off valve made for purpose. Many automotive designers have faced the same issues as Morgan (duh!) come up with the same conclusions that earlier Morgan designers have. Coolant shut-off valves are used by Audi, Ford, GM,Mercedes, Jeep, BMW, Volkswagon....etc. Over the decades, they have all come up with easier, more durable and effective heater shutoff valves, often incorporating a bypass. Buy any of the many available that suits you and your hoses. It is a simple matter to buy hose adapters and your nearest plumbing store.

They do away with the awkward choke cables by operating with a tiny solenoid, needing only a small electrical feed from a convenient little switch near the driver. Proper heating and cooling depends on the flow being OFF when it is off and flowing when it is OPEN. That means you want a valve that is closed without power to it and open when you flip the switch..for those that a bit more anal than I, they can also be operated by dimmer switches to adjust how much hot coolant you wish to flow into the heater matrix. I recommend them for all Morgans as even the post-1999s have NO system to close off hot coolant flow though the matrix, .making them even hotter, with everything off, than the earlier Morgans!

I have been using mine for 5 years without an issue.

WATCHPOINT: Shutting off the hot coolant flow to the matrix will NOT completely stop the hot air from entering the cabin. The Morgan design is not stellar. The engine bay gets very hot and the in-rushing air forces hot air through the matrix and into the cabin whether the flow to the matrix is closed or not. You also have noticed hot air from the engine bay travelling past the gearbox and up through the gear lever shaft to your hand! The air that enters past the matrix is hotter! My mate Lance, who lives in the southern US, deals with this problem by taping (aluminum tape) over the engine bay entry on the heater.

These valves come in almost any configuration and for any hose size...with or without integrated bypasses. They come in all sorts of materials as well..brass, plastic, threaded male, threaded female and those that clamp.

You need one that is open when unpowered. Run the electricity to a simple, easily accessible switch OR, simply attach it to the AC "on" switch and both tasks will happen simultaneously. (Maybe you should increase the relevant fuse an extra 5 amps while you're at it. If you need any advice, contact me.

Remember, as well, that keeping your cockpit cool requires other work.

WATCHPOINT: Shutting off the hot coolant flow to the matrix will NOT completely stop the hot air from entering the cabin. That seems logical but the Morgan design is not stellar. The engine bay gets very hot and the in-rushing air force hot air through the matrix and into the cabin nonetheless. You will have noticed hot air from the engine bay travelling past the gearbox and up through the gear lever shaft to your hand! The air that enters past the matrix is hotter! My mate Lance, who lives in the southernUS, deals with this problem by taping (aluminum tape) over the engine bay entry on the heater.

by Lorne Goldman, Hurricane & Vintage Air

Factory Air Conditioning & Its Problems

First, forgive me. I am not a fan of Morgan air-conditioning in trads. YES, I find most Morgan classic cabins hot, but that can be addressed successfully with non-invasive measures that complicate the cars and gobble horsepower. I don't give cabin heat much thought unless I am in someone else's Morgan and notice the heat I had 25 years ago. But the Roadster Group got me interested enough to examine the MMC climate system problems. Their cars are even hotter than earlier ones ever were! Sadly, the outsourced design that the MMC adopted is a recipe for inefficiency and damage. 

Morgan adopted airconditioning around 2004. I had seen US dealers design and install systems from as early as 1990. But Morgan did not cast their research net very far afield, a chronic problem they have. Once again, they used a nearby UK supplier. New Morgan suppliers are chosen on the basis of price and proximity, not quality, durability or suitability. This habit costs the FActry and the owners moeny and frustration. But Morgan component sourcing is quirky. For example, there is a famous axle supplier in Quaife.. ideal for a light Morgan and who has supplied the Morgan steering rack, taking over from Jack Knight since 2007. Yet Morgan chooses to buy too wide very heavy pickup truck axles from BTR (aka Dana) and shipping them from Australia!!! The list of such things is endless. 

I deeply researched and examined the design of this air conditioning system Morgan are being supplied with and indeed, some major failings in the logic of many post-2000 Morgan heating systems. I even went o far to call the aftermarket company supplying them and asked why air cold air conduit was placed a thing metal barruer away from a constantly super heated heater matrix. Sadly, the MMC chose to merely "added-on a patch" to their earlier heating system by way of AirCon components..compressor condensor, evaporator etc, to create a second source of refrigerated air and run it through the existing heating design. It is never wise to run two temperatures of anything side by side in the same space unless you want the blend of both to achieve something less effective than either can be. In practice, any aircon expert will tell you that running super cooled air over a heated (cabin heater) matrix constantly supplied with super heated coolant is unwise. That recipe creates condensation, (aka dripping water) and speedy rusting. The hot coolant supply to the cabin matrix on such Morgans has no on-off valve). It relies on the airflow vent only which any mogger from 1950s through the the mid-1990s will tell you makes no sense. The best attempt to stop the heat is to both cut off the coolant flow to the matrix, close the cabin vents AND block the vent on the bulkhead. Even with that, the source keeps radiating into the cabin through the prop shaft tunnel.

With a bigger-than-necessary cooling unit, you CAN overpower any amount of adjacent heat
. Sadly, this overpowering merely increases the horse power lost and creates MORE condensation. AND if the drain for this condensation is inadequate or it naturally clogs with debris over time, the entire climate system will regularly flood..most likely on the occupants legs and lap. ( The inner components will also rust, controls will become unworkable and/or seize or shear at the control knob stems..which is the experience everyone is having.  

Of course, one "fix" is to repurchase the same rusted components and wait for them to fail again but......

A cure?  

There are many, many other vehicles I ran across in my research with the same issue, namely airconditioning fighting with heating using the same distribution system. See above. They all found solutions, curiously the same solution that Morgan people did with the heating in th 1950s. They place a stop valve on the supply of the heater matrix.
However, they use electrical valves that functiion automatically off the cockpit controls. By the way, that opened my eyes. I have never been happy with the odd, badly chosen, traditional shut-off valve that Morgan heat systems have mounted on the bulkhead for decades, activated by a carburretor clutch cable.  An electric button-operated solenoid shut off is much smarter.