Talk Morgan Forums Thread Like Summary - Trad Air Condtioning

Hi again Burgundy,

First, I should mention I am a big fan (pun!) of the 3.0 Roadsters. Great spec and only a few problems to sort.

Some years ago your verdict came up on a Roadster forum. I have many Roadster friends and I put up what they suggest on gomog. They were discussing whether there was anyway to improve the less than ideal Roadster cooling. I also dealt with two fellows off-group in depth. Like many, their AC was feeble, its was leaking and their controls had seized. One contacted an AC expert contacted in Dallas, (overseas Roadsters come standard with AC). That fellow asked me to get schematics. Morgan had been begun outsourcing all elements of design and production a few years before and the AC was another area they did so. Don't ask me how, but I got the schematics under the condition of discretion.

It was easy to spot the problem of the supplied system. It HAD TO to cause problems. I gather from you they did not address the issue by the time your car was made.

PROBLEM

1. ALL earlier non-AC trad Morgans have an rather awkward valve on a old choke cable. It shuts off the hot coolant flow to the cabin heater, which is virtually a small radiator that heats cabin air going into the cabin and most often has a bypass directing the flow back to the engine water pump. Any non-AC trad owner will tell you that, even with the cabin heater vents closed, unless the shut off valve is closed, the matrix continues to provide heat, radiant and from the unpumped engine airflow. The systems continue to heat the cabin!

2. In the AC cars it is worse. The designer chose to use the same passage for the cold AC air as is used for the hot air. This passage abuts and is above the matrix.

3. The designer did not install a shut off valve. No one at the MMC caught that. The cold AC air must go through a hyper-heated passage over the matrix constantly charged with hot coolant. A BIG NO-NO. This is a recipe for tepid damp air and lots of condensation. Many of the sufferers complained of a wet cabin floor and rusted controls
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SOLUTION

For the cars made before a remedial fix, (if any) and before damage has occurred, the fix is theoretically easy. One must install a shut off valve and preferably a bypass for the hot coolant to return to the engine water pump before the climate unit.)

It is theoretically quite simple. And it works. And you can test it. The system has hot coolant flowing in and out of the cabin unit. Image below. To sorta test, merely clamp one of the hoses (in or out) which will stop the hot coolant flow. That alone might make a difference. However, I found that other manufacturers, like BMW use a dual purpose passage. However, they use a electric solenoid valve which stops the flow to the matrix and bypasses it back to engine water pump. I was so pleased with this that I switched (pun!) from a Morgan mechanical valve to a solenoid valve myself. I have now used it for many (12+) years. It does not break like the Morgan mechanical valve often does and I merely put in a toggle switch to replace the choke cable. You merely have to get a valve that is open when not active or power it from the ignition through the aircon switch.

I wrote an article on all this then forgot to add a link to the gomog Roadster page. https://www.gomog.com/allmorgan/CabinHeaters.html#BETTER

The solenoid valve (which should have three hose attachments, A. to the valve, B. from the valve to the matrix and C. from the valve to the return hose.) should cost about 35 quid which is the cost of the fix if you do it yourself. That is all you need. The result is your unit will stop leaking and the AC will be cold and dry.

Did I complicate your life?

gmg.

P.S. Here is a Roadster cooling schematic. I have others from the MMC. I cannot show the suppler diagram, but if you call Mark Evans or Mark Baldwin at the MMC they will probably send you when.

No George the 3.7 thankfully doesn't have the extra complexity of the oil filter heater/cooler fitted to what appears to be just S1 and S2 3.0 Roadsters, given three engine variants used.

As intimated I have written and recently updated an explanation of the coolant system unique to the Cyclone engine in the 3.7 V6 Roadster, based on observations and much thought about my own car, if anyone is interested?

Richard, thought this underside image might be worth tossing in. From a pranged 2016 Roadster.

Yes there are drain spigots on both sides of mine too but you will see that the form of the airbox is different on mine to accommodate the aircon evaporator. The principal of blocking hot engine bay air (and potential fumes) remains the same for aircon and non aircon systems.


Foam cut to shape to fit the top of the airbox.


I made the blocking piece from a sheet of PVC cut and bent into shape. Where the material was bent a crack opened but it is only in the upper surface and I will use a little black silicon to fill it. If ever I replace it I will probably use a piece of aluminium instead now that I have the shape needed.


Blocking piece in place.


How it looks after a few years of use. Note the impression left by the edge of the louvres. It only just covers the edge. Probably the louvres should have been placed a centimetre closer to the hinge.


Tube fitted to lower left-hand drain spigot. I only worried about the left-hand side because condensed water from the aircon evaporator was getting under the ECU cover and dripping into the footwell past the main cable grommet (the one where all the cables pass through to the back of the dash). The dried leaf is an optional extra


Showing the neoprene gasket that I place under ECU cover flanges. The idea is to stop possible ingress of water that could then drip into the footwell. After taking the photo I noticed that the cable grommet was a little out of place. I have fixed it


This shows the drain tubes at the bottom of the in-cabin part of the air system. If they do not exist it would be possible to fit them but it would not be easy with the gearbox cover in place. Even in cars without aircon I believe these drains would be desirable due to the possible ingress of rain water.
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This last photo shows an example of poor design that creates long runs of tube but, worst of all, the tube from the compressor to the evaporator has a section which runs behind the hot radiator. This could be resolved by swapping the position of the compressor and the alternator.. The tubes which run to the condenser (aircon radiator) that is positioned in front of the radiator are also excessively long and whilst this is not a problem for the system it is untidy and unnecessary. It is indicative of a "near enough is good enough" attitude to fitting the aircon system.