Just curious -
lifting the car (87 924S) on my two post lift with the arms under the jack points just behind the front wheel and in front of the rear wheel -
the drivers door closes and latches when on the ground, but in the air I can't close the door, the latch strikes differently.

so it's apparent to me the chassis is flexing. Any thoughts?

 

I would expect some flex. Any signs of rust in the rockers, externally or viewed from the door jamb vent opening? Possible that the door (top) hinge and attachment to the body (which is marginal at this stage of age and use) has the door position on the edge of working / not working when the car is on its wheels, and when further stressed, or possibly less stressed since there is less span between jack points than between axles, the door goes outside the fit tolerance at the latch. Can you tell if the door is missing high or low?

 

Yes - have noticed same thing on a jack/stands.
Van and others have noticed the shock towers spread about 1/8" or more depending if the wheels are on the ground or not - thats where a strut brace helps.

 

to spare the door hinges, especially on ragtops, set the doors on the first click when lifting.

 

No signs of rust in the rockers. The car looks pretty solid from that standpoint. The door is rising up a tad when the car is lifted, so the striker hits the latch high relative to when the car is on the ground.

I was just curious. My plan is to track the car and I’m wondering if the chassis flexibility will be detrimental

 

Joe, are you going to put a cage in it? The older I get, the less i’d want to be on the track in a car without a proper cage.

But it’s your car!

John

 

it has a welded 4 point rollbar but no plans for a full frontal cage at this time.
the 4pt might marginally help with rigidity but obviously not much since it's already in there and the car still flexes

 

Pretty sure those are not jack points, they were only used to move the car along the production line during assembly.

 

per Pelican Parts tech articles this is acceptable, and there really is no other good place for the lifting arms to go anyway. My 924S does not have the jack point in the middle under the door

 

That Pelican article is wrong, it’s been bought to their attention many times over the years but they haven’t bothered to change it. Read the comments at the bottom.

Please be careful. Those factory points are prone to collapse if used as they are not rated to support the corner weight. The factory support arms used that “cup” as a guide only, and an adapter supported the actual weight at the floor and not on that cup. They are also dirt/water traps and prone to corrosion so may even be weaker than when new.

You can place your jack at the front frame rail which is the approved and safe location.

 

The door opening shouldn't be affected by jacking like that, IMO. Never had that with any of my 924s, caged or not. Makes one wonder if, since rust isn't an issue, if it was crashed previously.

Either way, doesn't matter - throw a full (properly built welded) cage in it and go have fun! Definitely won't flex with cage...

 

I’ve never noticed any flexing on my 944. I use the below front points on the ‘frame’ that runs fore-aft. Does the 924 have this ‘frame’?

 

This will happen in any car. I have a 2 post lift as well and every car I put on it has the same issue that you are describing. It is completely normal, but I would not store it for a long time on the lift as to not inflict any permanent bending. Ignore any people that say that this is not normal because it is normal for just about every car.

 

I agree with Acantor. It's normal. Much better with a cage that triangulates the load points. If you're considering a cage, spend some time looking over what Porsche did on the 933 (D/P). It's surely not perfect, but a ton better than many of the cages out there. I probably have some photos I can dig up if there's enough interest in what the factory did.
MM
PS: Good cage = handling and safety. What's not to like?

 

thanks guys for all the responses. I agree a full cage would stiffen the car up significantly, but as it will be more street than track, I'd rather not have a full cage in the car at this time.
audi49 - yes the 924S does have the same frame rails. One of mine is already bent up (not my doing) so makes me wonder if the car had some sort of mishap in its former life