8valve

Its evident that some have the problem, others dont. May I suggest the following, but first a disclaimer; I cant do what I am suggesting. I live very remote in the mountains and can only get on the web with dial up at 24.4K, it takes minutes for me just to make a post.

I suggest some of you start searching the web, corvette sites and any other site where you may get a hit on C4 Roof Off. We need to go way back in archives, hopefully to when the C4 was announced and see if and when Roof Off Problems started. If we can find that C4 Roof Problems started after the car was (lets say) 10 years old, then keep searching and see if that is a trend with different year Vettes.

If, once again lets say problems start in a year model after 10 years, then whats failing ? Right now, in respect, We are just whipping a dead horse. We need background data to come up with the problem, then a fix.

8Valve

Klondike

If the targa top is such an important structural member on a stock C-4, then it makes no sense for the tire shops to want it removed when they jack up the car. You just can't talk them out of it though.
Just to demonstrate, I can jack up my car on one corner till 3 wheels are off the ground and I can still open the door.
I'm not going to try that with the targa off though!

Tom400CFI

The problem was known before the car was even released in 1983. Dave McLellan said talks about it quite specifically in the book "Corvette from the inside".

Here is some good reading from the man, himself about the structure, and how the roof plays into that;

JrRifleCoach

Always been a problem.

Look at the door lock pin area of early C4's and you'll find a pin and socket that help to align the door when closing. This was discontinued in the later years.

Roadsters were equiped with the cross brace to strengthen the frame.

Some aftermarket mfgrs sold a Targa Brace that was basically a roof panel frame without the panel. Just a cross brace so you could have the benefits of the wind in your hair and not feel like the car was going to rattle itself to death.

The old method of opening doors and hoods before going on a lift are unnecessary for the C4. You can argue till your blue with some shops and all you'll get is tired. Let them have their way and forget about it.

8valve

Tom400CFI;
Thanks for your post and the attached good reading. That answers the question once and for all...at least for me. I need to find the book you mention. Is the book just C4's or does it include C3's.

Thanks
8Valve

H P Bushrod

I looked at buying a triple white '92 vert a couple of years ago. I drove it and the cowl shake was so bad i thought something was wrong with the car (and the car only had 18,800 miles on it!). I passed on that one.

woody41

My 91 is pretty smooth with the roof off even over 100 mph. I grew up driving a Triumph TR 3 and just sold a 72 Triumph Spitfire, you have not experienced shakes and rattles until you take a drive in a British sports car....stuff even falls off from time to time...and they always mark their territory... My Corvette is the smoothest, quietest sports car I have owned, with the roof off or on.

Tom400CFI

The first two pics are from "Corvette from the Inside", by Dave McLellan himself.

Second is "The Newest Corvette, from A to Z51"

Both books are great reading. Both FOCUS on the C4, but give a lot of history that both educate and help set the stage for the discussion of the C4 design and implementation. Excellent reading for the C4 enthusiast.

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