Windshield problems!

DaveR · #1 (**permalink**) 03-07-2004, 03:22 PM

My windshield is wider at the base than the indentations in the body by about 1/2", which means that all the weight will be on the two bottom corners, with a 1/4" gap under the windshield all the way across the bottom. Should I grind a groove wide enough for the windshield frame at 90 degrees to the body dimples where it is supposed to sit?

Bruce Edwards · #2 (**permalink**) 03-07-2004, 03:43 PM

Dave,

I read your post three times and still do not understand. I may be having an off day.
Are you saying that the side braces on the windshield are past the indentation marked on your body or that the windshield is being hug up by the curve of the car so that it is not sitting on the body?

DaveR · #3 (**permalink**) 03-08-2004, 05:12 PM

Bruce

Sorry, I was in a hurry. I don't have the side braces or brackets on yet. I simply took the windshield out of the box and set it on the body. The outside bottom corners are too wide to sit down into the dimples in the body, they extend probably 3/8" beyond the dimples, outboard into the rectangle marked in white by the manufacturer to be cut for the brackets. I am assuming if the windshield corners sat down into the dimple recess, that the bottom of the windshield would sit fairly uniformly accross the top of the body, but it currently has about 1/4" gap, even though the giant seal on the bottom covers the gap from the front. I'm pretty sure that once the brackets are mounted, I will have to cut the slots outboard from where they are currently marked, because of the extra width. If I cut a 3/8" groove 90 degrees outboard from the front-to-back dimple, the windshield will drop down snug on the body, but this groove will probably cut through the body, and I will have to seal it from the inside. Maybe it doesn't matter, maybe the entire load of the windshield should be born by the brackets, and it doesn't matter if the bottom isn't touching all the way accross.

Bruce Edwards · #4 (**permalink**) 03-08-2004, 05:25 PM

Dave,

What angle are you setting the windshield to? If you lay it back will it still be off? It should fit flush across the car with no gaps. The only gaps we get are around the trim that fits around the brace and this is only 1/16 to 1/8 at the trim.
Can you get a picture? I will be happy to help if I can.

CRZN427 · #5 (**permalink**) 03-08-2004, 07:22 PM

DaveR,

When you go to put the slots in the body for the windshieild support posts you will have to insure that the posts bolt up to the chasis, in the holes provided, and penetrate the body so that the posts make no contact with the fiberglass.

If the posts do contact the body you could, and probably will, have trouble with the four screws on each side that mount the windshield frame to the posts. This is the infamous stripped holes in the brass strip ordeal.

When you make the holes in the body, so that the supports pass through, then you can attach the posts to the windshield frame (with the four screws per side) and sit the unit in as an assembly. If you happen to make the holes in the body a little too big they will be covered by the little aluminum plates anyway, if you really have a big hole make new plates big enough to cover.

On the B & B, you shoud be able to temporarily hold the posts to the chassis with C-Clamps while you locate where to drill the holes in the support posts.

The bottom of the windshield frame should not touch the body. The rubber seal lip in the bottom of the frame will contact the body and will keep the wind and rain out. To work effectively the bottom of the windshield should be at least 1/4" above the body. This gap will vary depending on the angle of the windshield.

The seal lip will, over time, make a wear mark in the body. I alwlays put a couple layers of electrical tape there to minimize the effect. I would replace the tape if the wear looked excessive. If the windshied frame touches the body it will make a bigger wear mark in the body as well as buff the chorme off the frame.

If you are concerned with the windshield "dancing around" there are center mount brackets that help keep it more stable.

Bruce Edwards · #6 (**permalink**) 03-08-2004, 07:36 PM

Dave,

You should ALWAYS put the windshield together before you try to cut any holes in the body. Use the marks on the body as a guide for the cuts only. We place heavy tape on the car to help mark the area for the slots. If the supports for the windsield are on the outside of the supports on the frame of the car use spacers do not try to pull over to fit you WILL break the glass.
I do think it is a good idea to use the center support. However most of the cars you see do not have this due to the windshield being layed back to "Race" angle. Check you side curtains if you have them to be sure of the windshield angle.
The windshield frame seal will keep the frame off the finish but it is my opinion that the frame be on the car for added support not held up off the body. The windshield frames are not strong at all and can use all the help they can get. More so if you are going to run your car with a top.

CRZN427 · #7 (**permalink**) 03-09-2004, 12:07 AM

One thing that slipped my mind on my earlier post.

At highway speeds, let alone racing speeds, the windshield will move back a little under the pressure of wind resistance.

If the bottom of the windshield frame contacts the body the frame could be distorted as it tries to reform itself to the contour of the body.

This could lead to a cracked glass (windshield) as will as increased wear on the glass body and chrome frame.

I ran my other Cobra, an LAE, for over 40k miles and seven years with the bottom of the windshield frame at 1/4" above the body. I added a center bracket after the first three years.

I never had any problem with the windshield frame protecting the windshield glass. The support posts are designed to do the job, the center clamp does help keep the center of the frame from lifting slightly at higher speeds.

I had my inside rear view mirror mounted to the top of the windshield frame. The center bracket eliminated about 90 % of the vibration in the mirror at highway speeds.

DaveR · #8 (**permalink**) 03-09-2004, 02:04 PM

BRUCE and CRZN427,

Thanks for the help. After talking to the manufacturer, turns out that there is supposed to be a gap. I would have never thought that this was the case, because if it's true, I don't understand what the dimples are for.

Bruce, I haven't set the angle yet, but it will not decrease the gap, only make it bigger. I'm thinking that I will lean it back as far as possible to minimize wind resistance.

However, some of the comments from CRZN427 make sense to me, especially the part about the windshield shifting at speed, and the need for room to allow for this.

My original concerns were not nearly as complicated as some of the points you have made (although they should have been) but simply that it wasn't consistent with my preconcieved notion that the dimples allowed the glass to sit lower.

CRZN427, how do you like your FFR versus LAE?

Bruce Edwards · #9 (**permalink**) 03-09-2004, 02:26 PM

By that do you mean the car manufacture said it should have a gap or the windshield manufacture said it needed one?
The windshield gets it strengh from the curve in the glass not the frame. The uprights that hold it in place should not move and if the windshield is flexing in the middle I would be a bit concerned. The way the frame and glass work together make it fairly strong, after all you can attach a top that is always trying to tear it's self off the car by pulling up due to the wind force.
I guess my problem is I do not drive at 150 mph and have never seen one move once it is bolted into place.

Bruce Edwards · #10 (**permalink**) 03-09-2004, 06:44 PM

Dave,

I have uploaded three pictures of the windshield on our car. Please note that we use the center support and the back side spacing that is shown in the pictures is a result of the gasket.
http://www.clubcobra.com/photopost/s...0&ppuser=18529

BMK · #11 (**permalink**) 03-10-2004, 04:11 AM

Dave

Hi

Sounds like you are getting good advice here. The only thing I found when fitting my screen was it was an advantage to open the bottom hole up on the posts.

This allowed me to move the screen back and forward until I found the right angle (look).

Between the top of the windscreen and the back of the body between the seats is 36". Does that make sense?.

My photos will give you an idea of the rake I used. I can move the screen about an inche forward or back.

Just one other thing... Once you fit the screen put plenty of "Silastic" or similiar sealant around the posts where they go through the body. Then put the cover plate on whilst its still wet.

Drops of water down those posts make a real mess in the footwells in heavy rain.

Have fun building

Cheers

Bernie

DaveR · #12 (**permalink**) 03-10-2004, 09:39 AM

Bernie,

Thanks for the waterproofing advice, there have been a lot of good ideas from this thread. I'm not sure the 36" measurement will be the same on my body due to variations from manufacturer to manufacturer, although I will check this dimension. What's your best guess as to angle?

Bruce Edwards · #13 (**permalink**) 03-10-2004, 10:00 AM

Dave,

Finish line now carries the correct seals for the windshield supports.

Art Burtt · #14 (**permalink**) 03-10-2004, 01:15 PM

I made my gaskets from a piece cut from tire tube. New wheelbarrow tube costs about $3 at Lowes

BMK · #15 (**permalink**) 03-11-2004, 03:37 AM

Dave,

I would say nearly 45 deg. But you may pick it better off the photos.

I used the rubber under the windscreen plates but put the additional sealant in. A low cost build tip.

I found at speed the screen did move slightly and heavy rain was getting in. Put the sealant in and found that it stopped that occassional drip of water.

Just experiment. The sealant sealed the rubber down onto the body before I put the plate on.

Sounds like you have it all sorted. Again good luck with the build.

Cheers

Bernie