I have my car all the way down to the shell. Its going on a rotisserie in the near future to get the bottom sand blasted and painted. It would be so nice to weld in some SFC's while its on the rotisserie. Has anyone done this? Or do you know what the effects would be. It seems to me that as long the doors line up it wouldn't be a problem.

Hello
That's a great idea and easy way to get to them...But you need the suspension loaded to weld them on so you don't have any chassis bind. If you have any other questions feel free to ask and I will be more than glad to help.
Thanks
Brad

Brad,

Thanks for the reply. Can you explain a little more about what you mean by chassis bind? Thanks. I understand these cars flex a lot. It seems to me that adding the SFC's with no weight on the car would be like making a solid frame and then sitting a body on that frame. I may be completely off but, its looking like I will be completing the car then welding in the SFC's.

Hello
Here is a example.....Say you were to jack up the front drivers side and then weld them on....That part of the vehicle would have a hard time relaxing and sitting at original ride height...Because the SFC were welded while the car was in the air..
Hope the helps
Brad

the chasis would be bent in the wrong ways and after the SFCs were added the body would not be able to flex back the proper way.



try jacking up one side of your car around the middle of the pinch welds....... than open your door....... the door will have a hard time opening because the chasis is currently bent and part of the door frame is now bent aswell and rubbing on the door preventing it from opeining and shutting properly, now weld the SFCs in and your chasis is stuck like that

Id opt to soda blast the underside Vs sand blasting too. Even with the doors bolted on there is still way to much flex and play with the chassis. your best bet is to do the what you want to the underside frist and install the subframes last. like everone else has said above

you know, thats the general consensus, but i opt to disagree.
i understand the reasoning, but i think that if the chassis is going to bend, it would be better to fix it in a state of total relaxation vs fixing it in a state of stress.
i guess what i am sayin is fix it like the right dwg vs the left, even though the left is how it sits on the ground naturally

That makes a lot of sence also. as long as you could get the car lined up ,etc on the rotisserie good. I couldnt see a problem welding em up on that. last car I dud I had the car up on jack stands. they were under the rear end and under the a arms. I didnt notice a diff. when put back on the ground.

another one I did was on a drive on lift like it was sitting on the ground. Again seemed fine. Both cars doors still lined up and open/shut fine. Same with T tops.

This can be argued all day. Fact is if you want them perfect put the car on a frame rack. The car should be pre-loaded to keep the correct geometry. If you where going to have the car in the lateral position during the install of subframes, Since most rotisserie utilize the furthers outside points of the car to mount the mass of the cars total weight is now focused in the very center and will bow the car out slightly in most cases this senifically increases the risk of the geometry being off and more strain on the car once its back in its natural sate of resting. You don't see them building car frames on rotisseries. . .

sorry, i was thinking frame rack in my head...
on a rotisserie, i wouldnt do it unless the car was upside down or right side up.
i wouldnt even consider doing it when the car is on its side

If i put the doors on the car and knew that everything was square then I cant see it being a problem. I could weld braces in as well. I guess i will make the decision when I get it on the rotisserie.

i would also put the hood and hatch on as well so you can be sure it lines up

so you ask what people think, everyone tells you not to do it, and you still want to do it?

No, I asked if anyone had done it. If I get it on the rotisserie and think that the car is twisted or not square then I wont weld them in.

Why don't you get the bolt in ones, just in case you need to take them out. I heard the bolt on ones have a thicker flange and are good to weld in as well.

It all depends on how you attach the chassis to the rotisserie? tell me how you plan to do this and I will give you incite as to how it is supported.

Pretty much you are 100% correct that as long as the doors line up you are great. That IS the limiting factor as long as you do not weld them in when the car is on its side with lateral distortion even though the door is latched closed.

might I suggest you put the car on the rotisserie WITH the doors on it- making sure in the upright position and clamp the SFC's underneath with good tack welds holding them in place.THEN, with the doors still opening and closing properly, flip the car upside down and finish welding them in nicely.

Its not rocket science people.

You just do not what the chassis loaded unevenly as if it were being jacked up on one corner of the car and the chassis being twisted by its weight fully loaded. This is a stripped chassis being equally supported and the doors close fine.

Thanks, thats the kind of answer I was looking for. The car will be bolted to the rotisirrie at the factory bumper locations. I didn't understand the answers I was getting about jacking the car up on one corner. I would think that anyone would know better then to weld them in with the car like that.

What I might do is put the doors on the car, get them lined up, the use some small pieces of flat bar on the back side of the doors and weld them shut temporally. Then put the car on the rotisserie, make sure everything is good then flip it completely upside down and then weld the SFC's in. Once it is fliped back over and the doors are cut loose nothing should change.

What a pain in the ***. way to much thoght into this. build the car then when your done with the underside put the subframes on and weld them with the car loaded on the grund or go to a frame rack.

It may be a pain in the *** but I am going to paint the bottom of the car. If I get it all nice and pretty under there then go trying to weld in SFC's later its going to mess up my paint job. Thats the whole reason for putting on the rotisserie in the first place.

I am sorry you had to even explain yourself. Rotisserie usually means show car.

that made me laugh dean...

After you weld the subframes on the rotisserie you should take the car off and have it acid dipped then e-coated then put it back on the rotisserie to assemble parts

Well I talked to a couple frame guys and got the same answer from everyone. These cars down to the bare shell are not going to flex on a rotisserie. Unless they are rusted out. I checked the car before I put it on the rotisserie and it was perfectly square. No twist at all.

So, I have one side of the SFC's welded in and will be getting started on the other side soon. From what I can tell the SFC's fit under the car just as they did when it was on the ground. I am pretty confident that it will be fine.

Thanks for the pics and update!