Hey guys, I was out taking some corners in my vert and when I got home I have a perfectly straight vertical crack in my windshield about six inches from the middle on the passenger side. It goes straight from the top to the bottom of the glass and there is no rock chip or visual cause. Do our cars flex enough to do this? Is this common to our cars and if so what is the remedy? My windshield was perfect to; this is a pain in my @$$.

 

If it was a coupe, I would think possibly, as the windshield is part of the structure of the car. On a convertible it is not part of the structure as the loads are transferred from the roof through the doors and floor.

If the windshield was damaged from installation or prior to installation on the edge it would propagate.

 

The windshield was perfect untill I was having fun with some local corners. I followed no cars and wasn't gone that long and when I got home a perfect crack. Never had this happen before. I didn't know if one front wheel was loaded more than the other if it could torque the windshield section and cause this. Every other time you can hear the pop and see the star and watch it slowly creep.

 

All windows crack sooner or later.

 

I don't see how that could be possible on the vert because the floor and doors and sub frame carry the load on a vert. If you are that worried about flex get sub frame connectors

 

To say that all windows crack over time... is not correct, something had to happen to it, or there was a MFG defect. There could have simply been something in the glass when it was manufactured. I have seen the heat of the inside of a car shatter rear windows because there was a defect in the glass, how I could tell was the glass exploded outward, not inward like it was if someone broke in.

I really suspect there was simply something wrong with the glass to start with in order for it to happen.

 

The windshield will see more stress on a convertible than a coupe. The flex of the chassis during your fun cornering was the cause of the crack. There is just not enough reinforcement of the chassis on these cars to make up for the top being taken off. Have you installed SFC's yet? I installed the Alston SFC's and it helped a lot on the chassis flex. I also installed a 3-point Edelbrock STB which ties into the rail just below where your windshield broke. I modified the 3-point STB into a 4-point with two additional bars that are welded to a metal piece that mounts to the upper radiator mount point to further minimize the flex. If you haven't done these modifications yet, I'd strongly recommend it. These convertible chassis will flex worse as they age.

Lon

 

Lon,
You definitely are more of an authority on convertibles than I... It seems counter intuitive, but like I said you are probably correct. I know that my convertible really moves around when going from my driveway to road, as we have the low curbs where they do not cut out the curb for the drive, and I can see the car flex... My T-top car before I installed the SFC's really would flex...

 

Well either way your car flexed and the window contacted the surrounding area and cracked it. It was either chipped before around the edge or simply to tight a fit.
If I were you I would buy some sub-frame connectors to hopefully keep the next one from cracking they cost no more than a window and will prevent you from needing another one.

 

What subframe connectors fit verts? I have UMI on my iroc and I love them but I know some will not fit a vert. If any of you have any pictures of your SFC on your car and what brand please let me know I have never had a windshield do this and it happened on a short drive with the top down sliding it around a few 30-50mph corners. Since I have tightened up the suspension it is like driving a go cart. I know I need subframe connectors in the worst way but I would probably a set that doesn't fit. Lonsal, I would like some pictures of your set-up as well as any other cars out there with a good tight suspension. Oh, and there is not one chip on the windshield since I had recently rain-xed all the glass and re-glued my mirror back on. It cracked 4 inches on the passenger from top to bottom; never had one crack like this.

 

Alston are the brand I use. I had them installed on my car roughly 2 years before I started TDS and started selling them on my web site. I like that they directly tie the front & rear subframes directly by the shortest path which is also the lightest. I also like the formed sheet metal cup on each end that wraps around the front & rear mount points snugly. You have the option of drilling your car body & bolting them or just welding them in. I have a 3" intermediate pipe and like that the Alston SFC's protect the I-pipe. When I hear them bang or scrape on a tall speed bump I smile knowing that they did their job protecting the I-pipe from damage. When you have the car on a lift you can rattle-can spray out the scrapes.

Lon

 

Thanks Lonsal, I know coupes fairly well but I admit to not knowing a lot about verts except that I have been trying to buy one since 1989 and have bought four t-top cars untill I finally found my 92 triple black Z. Now it's all I drive. I have a 90 ZR-1 Corvette Black Widow with 430RWHP and winds to 8000RPM and I haven't driven it since 2008. I will check on the alstons. Will UMI or BMR fit a vert? I like weld on stuff compared to bolt on where the frame is concerned. I would probably go with bolt-on in the engine bay though. Pulling the engine with welded things in the way would make for a long day and I want to put a new motor in mine before long.

2-1981 Z28 Camaros
1979 Bandit Y84 Trans am 4 speed
1989 Z71 4WD
1990 ZR-1 red Corvette
1989-90 Iroc 350 t-top
1992 Purple haze Z28 t-top
1992 triple black vert Z28
2002 Corvette yellow
2005 2500 Duramax 4 door

 

Oh I love the c4 zr1's way ahead of their time the problem with the verts is that they already have reinforcement on the outer pinch rail that gets in the way of most sfc's, and besides the ones that go there typically don't actually tie in the front cradle.

 

You can just do port work on a C4 ZR-1 and gain 100hp. They are an amazing engine but with 4 cams I had to take it to Oklahoma to Greg Vandeventer and Scott Skinner to get the cams timed and some other things done. It has a timing chain you could hang a man and his horse with. The ZF gear box is supposed to be the strongest gear box ever used by GM. It is heavy enough but does shift great. An amazing car and will go 200mph I PROMISE!!!

 

Oh god I see one in my future now. I was going to get a grand sport but
a zr1 would be way more fun. My first car was a 1990 black on black with the fx3 adjustable suspension and the six speed zf first mod was a b&m short shifter
It lacked power though dang l98's

 

The ZR-1s are very cheap right now. The engine parts are on the expensive side but I have bought about everything you can buy for one and I also know all the guys who mod them. They are well worth the money and the cool factor when you raise your hood is off the chart. The engine looks like something Darth Vador would wear to help him breath.

 

Ya Its like a tpi intake on steroids Pretty much double everything do you have any pictures with the valvecover off curious to see the lifters and cams.
I hate going to the corvette shows like bloomington and carlisle because I find myself drooling over the c4s more than any other car even though there is cooler cars I just love 80-90s cars for some reason

 

You can go to www.zr1.net and see about anything you want to see. They have cars for sale there, info, pictures etc. Mine has stock cams and does 0-60 in about 3.8 seconds. In a 1/4 I can leave easy and not spin a tire and turn 12.2 with stock tires not pushing hard untill 3rd gear since it just spins the tires. Greg Vandeventer is a good friend of mine and does port work on lt5 cars as well as other cars. I spent the weekend with him when we did my car and got to know him and his family. I did the valves in my car. All 32 of them. Me and Greg worked all weekend to finish the heads so Scott Skinner could time the cams. I bought some rare stuff from him while I was there. I got a pre production air horn from a prototype motor that there was only about 3 of. I got the air horn cover the motors were shipped to bowling green with. I got another throttle body that Greg ported for me. I got some small stuff also like emblems and rub strips for the cam chain tensioners. My motor is basically a black widow motor made by the same guys (Greg and Scott) except Doug Rippie officially made them. There are I think 18 official Black Widow ZR-1s but Mine is actually a little better with better porting and better pistons and rods. Mine is verified by Greg and I have a ton of e-mails and Greg himself to prove it. My motor went to Yale Oklahoma instead of Rippies shop to become a black widow motor. I rode in a guys car who was the motor right after mine and his is exactly like mine except he bought the big cams and his car is the only car that I have ridden in that is faster than mine. His is over 500rwhp where mine is 430rwhp. I wanted cams so bad but I didn't want to touch mine since it ran so good. Cams are also almost $2000.00 for all 4 at that time. I don't know how much they are now. I haven't priced any lt5 stuff in a long time. In 1990 a water pump was over $500.00.