Door gap when put on jackstands
Pro
Joined: May 2005
Posts: 515
Likes: 66
From: Grosse Pte. Mich.
Now that's funny...
This has always been my understanding. I have witnessed 3 different
Vette restoration shops who take special care when lifting these cars
for this very reason. It seemed to have nothing to do with rotted or weak frames either.
Just nature of the beast. In the case of a convertible, the doors were opened prior to lifting.
Vette restoration shops who take special care when lifting these cars
for this very reason. It seemed to have nothing to do with rotted or weak frames either.
Just nature of the beast. In the case of a convertible, the doors were opened prior to lifting.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
From what I'm reading here the frame on my '69 convert. is weak and about to fall apart. It has flexed from day one for me. With the top down, if I drive into a driveway at an angle the door ajar light often comes on briefly as a result of frame flex. When I put it on jack stands which I locate at the recommended jack points on the side frame rails, the back of the car droops slightly; the gaps at the back of the doors widen slightly.
With the hard top bolted on the car is much more rigid. The door ajar light doesn't come on on driveways and the entire car feels more solid, especially on a twisty or bumpy road. It changes the entire character of the car.
As for aluminum body mounts, my car missed those going down the assembly line. They are rubber.
Cheers,
Pete
With the hard top bolted on the car is much more rigid. The door ajar light doesn't come on on driveways and the entire car feels more solid, especially on a twisty or bumpy road. It changes the entire character of the car.
As for aluminum body mounts, my car missed those going down the assembly line. They are rubber.
Cheers,
Pete
Enough flex in the body/frame to turn on the "door ajar" lights would scare the bejezus out of me. One of my uncles had a 68 4-speed vert until about two years ago, and it would never flex like that when I drove it.
No one likes to hear it, but there is no way that the frame should flex enough to jam up the doors when the car is lifted. I don't know what's going on with some of these frame-flexing cars, but something isn't kosher.
Melting Slicks
Joined: Nov 2002
Posts: 2,231
Likes: 7
From: Fort Pierce Florida
The frames flex. I've seen it on every C3 that is lifted (there's five at my house now). I never had a problem opening and closing doors, but my gaps are set perfect on the ground and maybe open up a 32nd at the top when my '82 is lifted.
Pro
Joined: Jun 2005
Posts: 725
Likes: 1
From: FL.
Come on "Simple physics rational", All frames Flex , Jack points are there to minimize Flex. Convertables Flex More than Coupes, Remove the engine and have more flex than when the engine was Mounted..Rear diff. same thing..ect..ect. The C3 Frame would have to be Trussed and Gusseted to the Max to not flex, the factory never even considered it.
Instructor
Joined: Sep 2007
Posts: 138
Likes: 1
ALL CARS, including modern cars will flex. It's refereed to as torsional rigidity. Modern unibody cars are much more rigid than C3's (full perimeter frame). However, I wouldn't worry about a steel perimeter framed car breaking in half on the freeway any more than I would worry about a steel spring breaking in half.
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
They're flexing because the frames are weak. Jason, you just proved the point. A C3 frame SHOULDN'T flex when lifted, and one that does is a sign of problems. As I have said many times, my 77 has been on stands for 18 months and the doors still work just fine.
Believe you're OK all you like...but the results won't be pretty when your car cracks in half on the highway.
Believe you're OK all you like...but the results won't be pretty when your car cracks in half on the highway.
Burning Brakes
Joined: Dec 2007
Posts: 952
Likes: 0
ALL CARS, including modern cars will flex. It's refereed to as torsional rigidity. Modern unibody cars are much more rigid than C3's (full perimeter frame). However, I wouldn't worry about a steel perimeter framed car breaking in half on the freeway any more than I would worry about a steel spring breaking in half.
Anyone who thinks a Vette frame won't flex never read the power book. GM says they do. 
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Advanced
Joined: Jan 2006
Posts: 97
Likes: 0
From: Long Island NY
Frame flex
I've had them both ways. They all flex. Some flex and it shows up at the doors. Others don't show it as other components compensate for the flex. I would check the frames and not worry about it unless your doing some high stress driving.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
There's a difference between minor "flex" and "door-jamming, t-top shattering flex."
Pro
Joined: May 2006
Posts: 573
Likes: 5
From: Georgetown Township MI
When I put my car on a lift or lift it up on jackstands, I notice the gap at the top of the door become greater. That's not suppossed to happen right? I usually put the jackstands right before the doors on the front, but this has me wondering. I don't see any obvious frame problems...
last 5 months on jack stands. Once on the ground, everything
aligned back up. I opened the door and could lift it up and down.
I discovered my door hinge pins have weakened. I will be replacing in
the spring. I would do that first before worrying yourself over what
could simply be the hinges or hinge pins.
