Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) +4 GDI Air Temps

Hi Peter,

I had gone as far as I could in restricting Engine Bay Air into the top of the Heater Box but the entry air was still significantly Hotter than Ambient, so I wouldn't fit a Bypass if I were starting again, I'll have to decide on removing the Bypass but no rush at the moment.

BTW. I proved Rogers idea of extracting air via the Heater box today. Fitted a cheap £5 fan mounted in some foam, lit a Smoke Match in the passenger footwell and watched it pull the smoke out and up through the heater box.

Lots of little problems to work through before I have a proper implementation though.

Worth mentioning that whilst poking around heater box with my head in passenger footwell I noticed a significant hole in back of box behind radio although hidden underneath in photo.



With my hand in gap between back of box and bulkhead I could reach with several fingers and touch inside of footwell vent!

There is a hole in the back of the box for the radio cables. I don't recall from when I last had the radio out but the rectangular recess for the radio should be isolated from the ventilation system. Apart from any other consideration water (or condensate if an aircon is running) can arrive to the bottom of the ventilation system, that is why there are drain tubes. The last thing one wants is a wet radio 😲

I can see that both drain tubes show a small sign of having been kinked or squeezed. It is obviously important that these tubes are kept as open as possible to allow correct drainage of the bottom of the ventilation system-

On the subject of the intake air I can't help but think that if the bonnets were a little shorter and the shuttle top extended a little further forward that the intake for ventilation could be in the top of the shuttle and better isolated from the engine bay heat. It would need some trick system for sliding out the air filter for cleaning and/or replacing but that would not be difficult.

I can't help feeling that for several reasons, if I was ordering a new car or replacement bonnets, I would not get top louvres, I would only order side vents, and a scoop on the inlet side (perhaps even both sides for symmetry). Clearly the exit of hot air (pushed by the radiator fan) in front of the intake of the cabin air is problematic, and that is without taking into consideration the gap in the foam around the bonnet hinge.

Actually if I was re-designing the shuttle top I would also move the wiper spindles and change the degrees of rotation. the idea being that the blade should finsh vertical against, or close to, the driver's side windscreen pillar and park flat pointing to the passenger side. This would maximise the driver's clear view in rain.

I'm trying to picture how the heater box system works. Does anyone have a schematic or GA drawing of the assembly.

I'm guessing that the heater matrix and fan sit in the top half of the assembly i.e in the engine bay and the flap which cuts off the cabin heat sits between the top half and what appears to be simply an air box in the passenger compartment.

The radio seems to be just sitting in a pop riveted tray inside the airbox.

In other words, if one took out the radio tray and filled in the aperture, one would simply be left with the airbox.

Or are there some other gubbins lurking in the airbox in the passenger compartment?

It's Richard's photo above that got me thinking.

You can confirm the flaps operation by looking horizontally through the forward facing cabin vents Bob with the help of a bright light source. The flap should drop closed (with a gentle thud) onto a soft seal just above when the bowden cable control is operated.

The radio seems to be supported by a universal slotted metal carcass incorporating the usual locking mechanism.

Thanks Richard,

Just had a look and I can indeed see the flap moving with the control knob,

You can also see the bottom of the heater matrix .

What it has shown me is that my flap is neither closing nor opening fully as I can just reach it with my finger and move it a bit even when the knob is hard over open and closed.

I suspect the control quadrant detents need cleaning as I've seen in another post somewhere on here.

Certainly answers why I always get some hot air even with the knob suggesting fully closed.

Thanks again Richard, such a simple check but it reveals a great deal.

Ivormog, I wrote a piece on here (TM) with pictures showing the flap operation & how to remove the vents so you can get to the end of the Bowden cable. Someone may be able to find it as I can’t. Me & website searches don’t work. I used some brake grease for lubricant. You may have to release & adjust the dash end of the cable if the flap won’t close. (Caution with the crank as it has a small ball that can get lost, but to adjust the cable you shouldn’t have to dismantle that)

Is it this piece, IcePack?

https://www.talkmorgan.com/ubbthreads.php/topics/767556/re-heater-control#Post767556

Thanks IcePack and Heinz. That link to the heater control post does show the removal on the vents and a lot of other info as well.

The vents were relatively easy to remove (following Icepack's instructions) and certainly gives good access to the flap and Bowden cable.

I've actually taken some photos inside but they are inverting when I upload to TMimg which makes them quite confusing to view. (See my plea for help on another post)

I think there are actually 2 flaps in there as I can see the main Bowden cable connection that operates the front flap but then there is a linkage to a second flap that seems to operate some thing at the back of the heater box. (looking through the vent)

A picture paints a thousand words so I will post if I can solve the inversion issue I have.