Jacking up 328 is this normal

I don't know about the roof; I can tell you that my passenger's door cannot be unlatched or opened, when my car is on the lift, but my Driver's door works normally.

I'm afraid some sag must be normal, when the car is supported even at the correct lift points... certainly the entire power unit is cantilevered beyond the rear lift points, so it seems physics is not our friend, in this scenario.

Next time I put mine on the lift, I'll measure for any change in the roof opening, and I'll report back here.

 

If it's a GTB, that would be a big problem
No, I think 3/16 should be okay.

 

I have difficulty opening the passenger door as well when on the lift. Haven't noticed anything at the roof, will check next time. But not sure why it would pull away on the back where the latch is, shouldn't it do that on the front?

 

The place where I have tires replaced has always unlatched the doors and the targa top before lifting.

 

If lift points are at the ends of the car, the load is in the middle and top of car is in compression and bottom of car is in tension. Hence smaller roof gap.

If lift points are inboard, the load (engine) is at the end and the top of the car is in tension and bottom of car is in compression. Hence larger roof gap.

 

If you lift on the wheels, I'd expect your car would not flex from sitting on the ground. (Duh!)... It's just the physics described by i-velocita above.

 

Wouldn't that allow the car to flex even more? I would think you want the doors latched to increase the stiffness in the body?

 

Yes but they may need to get in the doors and also don't want the targa to break in any way. I have heard some 80s and 90s corvettes have broken their windows when the car flexed on the lift. Maybe they are just being cautious because of this.