The revised revised plan for working on the Z starts with recognizing that the car is currently structurally unsound. As I cut out and replace parts of the body there is a good chance that it will bend, flex, and warp. This leads to a variety of bad outcomes, like doors that don’t fit, cracking windshields, and suspension problems.
Two things need to be done to minimize problems: first, reduce loads on the body as much as possible. This means pulling the engine and transmission.
Second, reinforce and brace the body before starting work.
I was already resigned to pulling the engine. I don’t know if a full rebuild is needed, but at a minimum I need to pull the head off and check it closely. It would also be a good idea to look at the cam and bearings and to replace all seals and gaskets.
Working on the fuel injection, ignition, emission controls, and water pump is also easier with the engine out of the car.
The transmission needs front and rear seals replaced. And it would be crazy to not replace the clutch while everything is apart. You know, if I’m going that deep into the transmission I might as well replace the bearings and syncros. All of this adds up to a rebuilt transmission.
With the engine out and fenders off it is much easier to work on the inner fenders. I need to find any rust in this area as well as any “repairs” that need to be repaired. Yes, I’m looking at you, battery box!
Removing seats and carpet allows you to work on the floor as well as reducing weight.
The best recommendation for reinforcement is to remove the entire interior and weld in multiple cross braces. Most people don’t go that far.
The most common approach is to remove the doors, make custom brackets that bolt to the door hinge and latch mounting points, and weld a piece of steel tubing between these brackets. This helps maintain the shape of the door opening. Since nothing is actually welded to the car, you can remove these braces when the job is done.
You can also bolt removable cross braces to these door braces, further helping maintain the shape of the door openings.
The recommended approach is to replace the frame rails first, making sure that they fit the subframe attachments front and rear. Once this is done you can install the floor pans, fitting them to the firewall, inner sill, rear floor, and transmission tunnel.
After finishing up the frame rails and floor, move on to the rocker panels. And, if necessary, the doglegs at the front and back of the door. When this work is finished it will restore the structural integrity of the body of the car.
I will then move on to the engine bay. I can already tell that work is needed in several places. This whole area will need close examination since it includes the structure supporting the engine and front suspension.
Last will be the front fenders and rear quarter panels. The front fenders are largely cosmetic, so not a great concern. The rear quarters, on the other hand, are both cosmetic and structural. It will be interesting to find out how much work the back of the car needs.
I’ve ordered a set of Apex Engineered frame rails. These have good reviews. They are considerably thicker and stronger than the factory frame rails. They also have extensions which go back all the way to the rear sub frame – this is supposed to make the body stronger and stiffer than the factory frame rails.
I’ve also ordered an assortment of body panels from KlassicFab Vintage JDM: complete floor pans, rocker panels, and patches for the rear wheel arches. This gets me started with things I know I need. For some reason I suspect this will not be my last order of body panels…