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MG MGA - Hood to windshield frame seal

I’m looking for help for a long lingering nuisance. I completed my frame-up restoration on my 1960 1600 about 5 years ago, and am very pleased with the car, However, on the rare occasion that I have the top up, the wind noise and air entering the cockpit between the windscreen frame and the top rail is extremely high. At highway speeds, the incoming air creates enough pressure within the cockpit to pop the sidescreens out. I can correct this by sliding the side windows open but that defeats the reason the top is up - raining or cold. I did a test by adding a “gasket layer” of plastic closed-cell foam (about 1/8 inch) and it greatly reduced the incoming air over the windscreen frame.
Did I miss something in building the top? There is only a thin layer of canvas over the wood frame to interface with the metal windscreen frame, providing a very poor “seal”. Should there be some sort of rubber seal on top of the canvas or padding under the canvas?

There is the welting around the edge of the top but it seems to do more to direct the air into the cockpit than to seal it.
Bruns

The hood material should extend down over the top of the windscreen by about 40mm.(one and a half inches). That would/should prevent air rushing in.
The side screens should also have a small metal clip to hold them tight against the windscreen side frame to prevent them blowing out.
Barry.
Barry Gannon

Do You have the metal clip in the middle pulling the head rail down?
Dirk Van Ussel

I had the same problem when I first got my roadster, probably because the wooden front rail on the hood is not exactly the same curve as the windshield to frame.

Fitting a centre clip helped to reduce the gap and much reduced the amount of air and water blowing through it, but it was still a pretty damp experience whenever it rained.

So I took the advice of Bob West and fitted a rubber seal along the entire length of the wooden front hood rail, specifically in the centre of the edge of the rail that is in contact with the top of the windshield frame.

The seal has the shape in section of a capital letter D and is about 1/4" wide. I glued it to the centre of the rail using contact adhesive and it ran the full width of the rail (between the holes for the windscreen pins) at each end.

It has completely sealed the windscreen top.
I intended to put little sections of the seal onto the short length of the rail on the outside of the holes but, because I don't seem to have any leaks from there, I just haven't done this.

I have a picture of the seal somewhere and I will post a copy as soon as I find it.

Cheers
Colyn
Colyn Firth

Barry – The hood does have the overlap (I will have to raise the hood again to measure how much), but it just seems to act as a “scoop” to direct air.
Dirk – I do have the latch at the center of the windshield, but even with three points to pull the hood frame down tight, (center latch and two outward posts) the air still pours through.
I think Colyn has the answer I was looking for. The only way I am going to get the two hard, non-conforming surfaces to seal is with a gasket of some sort. I looked at some gasket material at the big box hardware store that has the cross section you described – I think it was for widow sealing. Is this what you used? It was soft, which would be good for this application, but looked pretty soft ad vulnerable. Given how seldom I raise the hood, this would probably be OK, however. Any info on the seal you used?
Back to Barry – I do have the clips for the leading edge of the side curtains (anti-rattle clips?), but have never installed them. The side curtains, as I remember, are aftermarket and rather ill fitting. Closing the door with the side curtains installed requires hand fitting the rubber seals on the side curtains under the hood material as the door is closed. Pretty easy standing on the outside of the passenger side, but more difficult from inside on the driver side. I don’t see any way that the clips on the curtains would slide easily behind the windshield frame as the door is closed. I admit I have never actually seen the door closing action on a correctly functioning car since most everyone has the Hood stowed except for inclement weather.
Bruns

I had the same issue on my MKII and solved it with a thin strip of open cell tape attached to the bottom of the header rail. The open cell feature allows the tape to easily follow the contours of the rail.
Nick Kopernik

When I restored my 1600 some 30 years ago I added a thin strip of foam on the wood prior to wrapping with the hood material to create a good weather tight seal.
To confirm my memory I just looked at the hood and it is still soft to the touch.
I have been caught in a few torrential rain events over the years without any water coming in. The A I had in high school, was solved by adding small “C” clamps during winter driving.
L Frisch

As promised, the picture of the rubber seal that I have glued to the front hood bow rail.
It is about 8mm wide, it is hollow and has the cross section of a capital letter "D". The flat side of the "D" is a little wider than the rounded part which gives a larger surface to apply the glue to.

I used a contact adhesive and this has lasted over 10 years.

As I mentioned previously, I installed the seal between the holes for the windscreen pins and intended to fit smaller pieces of seal later to the short section of hood-bow to the outside of the holes.
However, I have never had any rain water leak through these outer sections and so I never thought it worthwhile.

This rubber seal in conjunction with the centre rail clip has made the top of the screen completely leak free.

Before I fitted this rubber seal I tried using a self-adhesive foam strip which was advertised and a window draught seal, but this never really stopped the leaks.

But, I still get drips onto my knees from rain that seeps through the bulkhead from the heater shelf, fortunately, it is usually warm water which makes it less unpleasant! :^)

Cheers
Colyn





Colyn Firth

A sure way to solve the issue of water coming under the lip is run a strip of duct tape across the windscreen to hold down the flap and terminating around the windscreen post. I use colour matching black tape to suit my hood. (Easily removed when you need the concours look).
The other items to ensure a water free cabin are the short foam strips between the windscreen frame and the scuttle- this stops water tracking along the small gaps where the piping passes under the windscreen frame. Next you need to ensure your side screens are a good fit against the windscreen posts and the hood flap along the top of the side screens (this takes a lot of fiddling to get perfect). Also use the clips that hold the side screens againt the windscrren posts to ensure windage doesn’t create a gap there (fold back Bulldog clips are affective for this job). And carry a small towel to mop up any drips that sneak through - remember you are driving a car designed +60 years ago so it will never be as watertight as your SUV.
Mike
PS when the weather forecast says no rain take the hood down.
Mike Ellsmore

A strip of duct tape across the edge of the flap does work well Mike, but here in the UK, by the time you have the hood up, it is too wet for the tape to stick to anything.
I have only used it on a couple of occasions as a temporary measure when the threads have stripped on the wing bolts and I couldn't secure the hood.

When I have to fit the hood, I often drive without the side-screens fitted, you get almost no rain coming in through the sides and it gives me much better visibility too.

Cheers
Colyn
Colyn Firth

Hi. I fitted a foam strip to the underside of the wood rail before fitting the vinyl covering(see Anglo Parts Cat. #30 part). This will then seal against the windscreen frame when fixed. Cannot confirm whether it is water tight as I have not put the hood up since rebuild.
Brian
Brian Paddon

This thread was discussed between 29/12/2021 and 09/01/2022

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