Getting ready to hang front sheet metal. Any helpful tips on the best way to get everything aligned up?
I would lightly snug down anything you install because it will take multiple adjustments to get it right. Everything you move or adjust will probably effect several different alignments/gaps. The core support could have to be moved one way or the other to square up front end to align the hood properly. It's easy to get the fenders & valances aligned to what really looks good only to find out that the hood alignment requires the core support to be moved left or right to square up for the hood. Final fit and adjustment require everthing to be installed, because it all must play nicely together.
^+1 Getting every panel close to perfect can be a time consuming and frustrating chore. These initial steps can help. 1. Make sure the subframe alignment holes are true to the body before you hang anything. (The alignment holes are next to the subframe bushings near the firewall.) 2. All four wheels should be on the ground to be sure the doors are aligned properly. (Take a pic of the door gaps at the rocker, quarter and the front edge of the door by the "A" pillar... Post them.) If the doors are too far outboard... You will have wide hood/fender gaps and you will need to move the doors inward before you go any further with the fenders/radiator support or hood. Good Luck!
I have never been able to align front sheet metal with the car sitting on the ground... why? Unibodies have inherent chassis flex without all the metal in place as everything together triangulates and stabilizes the entire assembly. The subframe will basically "hinge" at the firewall... With the engine trans in the car you have a great deal of weight at the firewall area _ BEHIND the front wheels. Why does this matter? Hinge at the firewall will lessen the distance between fender firewall mount (behind the hood hinge mount) too close to the radiator support fender mount bolts. BRINGING your top gap of fender to door too close. EXAMPLE - If you put a jack under the subframe midway between mount position 2 and 3 bring it up to the subframe and then begin lifting the car... how many inches up on the jack before the front of the subframe begins to lift up? Supporting the vehicle with 4 jack stands under the subframe and 2 under the rear end will ensure your chassis is not firewall hinged thereby closing the door gap at the top. All of this being said... I truly hope you are doing this PRIOR to painting or at least the panels were PROPERLY aligned prior to painting. After paint is not the FIRST time to be gapping panels.
I don't know....maybe in an extreme sense...I have pulled the front clip more than a few times and never had a problem putting panels back on. GM didn't assemble these cars with them on floor jacks.
You're right they were not on floor jacks... However they were supported under the frame rails when the sheet metal was hung - Unitized body cars typically have their sheet metal installed in the body fitment area prior to mechanical assembly, thus there is no mechanical, subframe, or running gear in the vehicle. With a full frame car this is not near as much of an issue. I will give you that if the engine, trans, complete interior dash heater box, and glass were not in the body there would not be enough weight bearing down at the hinge area in order to cause much, if any, deflection.
