SUNROOF DRAINAGE - RL, RM, RN

[Martin Prior]

I'm baffled.

The sunroof wells of pre-RP Box saloons have a pair of drainage slots at the front leading into the windscreen head.  This seems like a VERY BAD IDEA.

Where is the water supposed to emerge?  The examples that we have here are so decayed (I wonder why) that I can't identify any outlet.

[Steve Jones]

They drain through the front of the roof into the external gutter that runs along the top of the screen. The outlets onto the gutter is covered by a small aluminium cowl. The water then drains out of the gutter onto the scuttle via a pair of holes in the gutter bottom at each side. I've just taken a couple of photos of mine doing exactly that as the car's stood out in the rain. Will post on here once I've compressed them. And yes, without doubt it is a very poor idea!!

Steve

[Martin Prior]

Thanks, Steve. I look forward to seeing the photos.

[Steve Jones]

  Roof Outlet.jpg (Size: 230.36 KB / Downloads: 356)

Here you are, Martin. Behind the cowl, there's just a simple hole through the front roof timber. If you want a photo of that, let me know and I'll take the cowl off. My roof works reasonably well. The main problem is that water drains through the holes in the gutter under the cowls, hits the scuttle and runs down past the side air vents and, in heavy rain, comes into the car via the slight gap around the closed vents. Yes, it is a crap system and make no wonder that many have sealed the roofs over historically. 

Steve

[Martin Prior]

That's great, Steve. Many thanks. This will be a very useful reference picture. Just for the record, could you please confirm the model and year of your car?

I'm just in the process of shaping a couple of timber window heads for RL/RMs. I've made repros of the pressed steel channels that collect the water, with the extensions that pass into the head, but was stuck on how and where to bring them out - stupid, really, as I must have seen these before without taking enough notice.

Could I ask one more favour? What are the width and depth measurements of the cover plates.

It's now obvious that the outlet arrangements must be completely different on the RN, although the upper end appears to be near enough the same. Another puzzle to solve!

[Steve Jones]

We're away at the moment, Martin, so I thought I'd have nothing to measure with but, inevitably, Mrs. J has a sewing kit with her so 2 3/8" x 1". It's not flat being raised to its lower edge. The car is a early RM (wider scuttle than an RL). To be fair, the sunroof system, whilst being pretty crap, does work reasonably most of the time. The big issue is that like any drainage system its success or otherwise depends on its pinch point. In this case that's the holes through the front of the roof and in very heavy rain, the channel to their rear that feeds them becomes overwhelmed because the water can't get away through the holes to the outside fast enough and the excess pours onto your knees!!!

Any more or any further dims, just let me know.

Steve

[Martin Prior]

Wonderful! Thanks very much for all of your help.

[Dave Mann]

Here's a photo of an RN windscreen peak with the bottom removed showing one of the sunshine roof drains which exit just in front of the windscreen.
  Windscreen peak drain.jpeg (Size: 24.65 KB / Downloads: 278)

[Martin Prior]

Thanks very much, Dave. That's the RN sorted. What a truly horrible arrangement - the car that we have here has rotted out completely around these outlets.

[Dave Wortley]

When travelling, the rain is blown back up the gutter hole and sometimes spills over the gutter and gets in the passenger compartment. Agreed, another one of those Austin apprentice draughtsman designs.