windshield

[aumoore]

I have developed a crack in my windshield and am thinking of converting to a lexan or some other type of plastic windshield. Any experience with the plastic windshields? Please note I do have functional windshield wipers that are sed in emergancy situations like getting caught in a sudden rain shower.

This crack developed after running up to 120 at Roebling road road course. I did not see it untill after I had loaded the car and drove about two miles from the track? It starts in the upper left corner and travels in a 45deg anglel toward the middle of the dash.

[Richard Hudgins]

aumoore,

Lexan windscreens work very well. You have to make sure that they are coated with a good anti-abrasion polymer.

We use Racingshields.

there are some other suppliers out there, but I have not worked with them.

Speedglas

Polyshields

(Check the FFR board, I think that David Borden has some experience with lexan shields.)

[Steve R]

aumoore,
Fix the root cause of the problem first. your windshield frame is most likely mounted incorrectly. This is a somewhat common
occurrence when kits are assembled.
Steven

[terry lee]

Ruble,
My advice is stay away from "Track Events," your record isn't too good.
Like some guy says here, "It's only Money"
I cracked mine also, don't know exactly how; but I'm sure that pulling on the upper corner to help exit the car hasn't helped matters.
I emailed "Racingsheilds" as recommened by JBL for a replacement.
I'll keep you posted on my results.

TL

[aumoore]

I do not think the windshield glass in these cars are of the same quality as those found on our daily drivers. The cost is pretty high too. I had a windshield replaced in my Taurus and it only cost $175 which was paid for by my Insurance. I cannot buy the glass for a Cobra windshield for that.

If I can get a good quality Lexan type of windshield that will not scratch when you look at it I think that would be the way to go.

As for my track time I am addicted. Why do you think I am looking for a plastic winddhield, sticky tires and a racing seat so I can drive without trying to hang on.

[Richard Hudgins]

Steve R,

I think that you are correct in the mounting causing the problem.

However, I do not think that that it is matter of the installation in most cases, but rather that the mount structure is not strong enough in a torsional load condition.

If you look at the windscreen mount/dash hoop structure areas in most roadsters, they are not very strong in torsional stiffness.

Therefore, under heavy loading (Such as track use with slicks, etc.) the windscreen frame is subjected to twisting as the underlying structure deflects under these severe loads. (Note: if you do a little search about windscreen breakage, you will find a very high percentage of these breakages occur during track use. Try the FFR forum, there is plenty of info about this there.)

terry lee,

Pulling on the upper corner as you get out of the car does the same thing as mentioned above. Torsional loading. NOT a good thing on this windcreen design.

The nice thing about the Lexan is that you can stress it much farther then you can glass and still not crack it. (Of course, you do have to be very carefull with hydrocarbon based solvents around polycarbonate as it will cause chemical stress cracking and hazing.)

[Roger Upton]

Richard Hudgins is pretty correct here. The structure the windshield is attached to is flexing but, what is causing it to flex is the question. This is due to the frame twisting you can watch a sign of this, if you will watch on most of these English roadster kit cars the gap in-between the door and the part of the body that is the top of the dash is changing as you drive down the road, especially during hard cornering or going over bumps in the road.
A stiffer chassis is the answer for this problem.

Roger

[aumoore]

I have been told that the windshield can push back in the middle from wind pressure at speeds over 100?

Almost any roadster/convertable has some chassis flex vs a solid roof car.

Hell Maybe I mounted it wrong. I need to check to see if I shimmed the support brackest so they did not have any stress induced as I tightned them.

[Rick Parker]

I too am faced with replacing my windshield. Yestereday I had the opportunity to speak at length with a vendor that installs glass at our Dealership. He made a point of saying that the glass in this type of installation must "float" in its mounts, ie: it must not be rubbing or have any contact with the metal frame or the screws and be free of any torsional twist which has been addressed previously. He recommended using some sort of polyurethene in a tube (frequently used in the glazing trade) unsure of trade name or brand to mount and insulate the glass panel in the channels of the frame. He assisted in finding a souce for the glass and was quick to say that part of the reason for the frequent breakage is that the majority of these panels are not tempered glass but rather just laminated. He went on to say that a tempered panel will accept much more twisting before it breaks, but they are about twice the cost.

Seems that the glass for these cars is sourced fom the East Coast exclusively.
Has anyone found a West Coast source?

Rick