Vehicle body straighening advice

[bigdry]

Hello all, wonder if you can help me with some info?
I am currently restoring an old Lancia Delta Integrale rally car.
As you can imagine it has seen some action on the past and isn't the straightest body shell in the world.

I have restored many car in the past and have experience with welding (mig, oxy, spot , arc) and feel confident in the workshop to tackle most things. However one area that seems to be shrouded in professional mystery is the use of body jigs and chassis tables.
What I would like to do on this car and future projects is buy second hand a body jig (there're lots of different kinds on the bay) and firstly check the bodyshell is straight by comparing it against manufacturers data. Then be able to straighten it if I need to , then be able to remeasure and hold down whilst finishing all the other work (seam welding and roll cage fitment) to ensure the least amount of distortion as possible.
Can anyone suggest a suitable system they have used that would suit the experienced but still only very keen amateurs home restorers budget?
Also do I need a separate jig and measuring system or is there a combined system? Manythanks

 

[rtbcomp]

You can check straightness by standing the shell level on stands on a level floor and drop perpendiulars with a plumb bob from the same points on each side of the chassis, marking the floor where the bob touches it.

Move the car away and draw lines between diagonally opposite marks and if the body is straight these lines will intersect on the centreline of the car.

 

[superls]

there was a good read posted not so long ago, someone restoring a datsun 2*0Z, he made a jig. ill see if i can find it.

 

[reno]

I think the man you really need to ask is Malcolm. He made a jig using channel for aligning a Renault 4 chassis. As far as I'm aware he is now using the same base jig but with the additional pick up point for straightening a Datsun 240Z.

Try this link it's from the mig welding tutorial - http://www.mig-welding.co.uk/chassis-jig.htm

Hope that helps!

Cheers, reno

 

[malcolm]

Here's the 240Z jig - http://www.vord.net/cars/240z/chassis-jig.htm

The Datsun is bent. Some fool removed a lot of panels and welded them back on badly holding 15mm of twist at the front. As the panels need to be removed and welded on properly I'm planning to remove enough and let the car flop onto the jig.

To pull towards the jig you'd need a strong jig frame. My C section frame isn't nearly strong enough in torsion for any pulling - it is less stiff than a car. I've only ever seen it done using massive steel plates set into the floor. (That's how we torsion test new cars).

Suppose if you had the space to the side you could attach I beams to each end of the jig, have them meet some distance to the side, and use the leverage and a bottle jack to sort twist. You could probably do some delicate stuff with serious leverage. For some things you can push against the car - door frames for example.

 

[brookie456]

You can check straightness by standing the shell level on stands on a level floor and drop perpendiulars with a plumb bob from the same points on each side of the chassis, marking the floor where the bob touches it.

Move the car away and draw lines between diagonally opposite marks and if the body is straight these lines will intersect on the centreline of the car.

Simple is best, gravity doesn't lie, good luck with the job, well worth doing, an Integrale is the most "sensational" car i have ever driven.

 

[bigdry]

Well gravity wont stop it warping & distorting when i weld it! yeh grales rule despite having the weakest, flimsiest bodyshell imaginable - maybe that where the magic lies...

 

[brookie456]

Well gravity wont stop it warping & distorting when i weld it! yeh grales rule despite having the weakest, flimsiest bodyshell imaginable - maybe that where the magic lies...

Nah, ask Malcolm, had fried rice in more substantial containers than a Renault shell

 

[pedrobedro]

I've used bolts, chains, angle iron brackets, threaded bar and scissor jacks plus all sorts of weird home made contraptions to pull chassis rails and body back into shape. It's handy if you can get an original to take measurements from.