LS1 Conversion, A Retrospective Build Thread Options

[andys]

Here's the start of a retrospective build thread of my LS1 conversion. It took a few years to get it done mostly due to not wanting to be a slave to the project, and work on it for the enjoyment; and of course when family obligations allowed......teen daughter and high maintenance wife (IMG:style_emoticons/default/biggrin.gif)

What I started with was a local orignal owner '75 2.0 with 139K miles. The original owner "drove the heck out of it" until something died in the electrical system and he parked it in the garage for 14 years, as evidenced by the renewal tags. Only body damage was when he submarined the rear of a Mustang and creased the hood and flattened the left signal light pod. Otherwise, it was a good condition rust free (SoCal) car.

Brief specs are: '01 LS1 Z28 motor, Audi 01E 6 speed tranaxle, 911 front suspension, custom made rear trailing arms, Koni shocks, 993 wheels, and AC.

Below, are photos of what I started with, and what I ended-up with. I'll do my best to re-trace the build process, so if you have any questions along the way, please ask.

BTW, how does one place text between photos in the same post?

Andys

[andys]

Let's install the Engman chassis stiffening kit. In preparation, I pre-fitted the plates and maked through the holes in order to grind away the paint to expose fresh metal for welding. While trial fitting, I discovered a few problem areas that required some attention.

I first noticed that the plates are not in intimate contact with the longs due to the longs not being flat; some areas are slightly bowed out (convex), while other areas are slightly bowed in (concave). So, the areas that were bowed out, I took a rubber hammer and gently hammered these areas flat. This helped reduce the gap at the bowed in areas to a somewhat reasonable amount. As any welder knows, a gap between plates like this will result in excessive shrinkage, and of course reduces the structural advantage.

I noticed too, that the seat belt anchors did not line up with the pre-cut holes, so some work was needed there. Also, the plate that goes across the rear required clearance notches be added for the ribs in the floor pan. Other areas requiring detailing were additional clearance around the cross brace where it meets the long, re-positioned holes so as to line up with the lower backpad screw holes, and the speaker grill screw holes needed the same attention. Once prepped, the work could start.

The chassis was placed on jackstands (at the donuts) and shimmed level. I first measured the door gaps in three places on each side. Then before welding, I placed a jack under the chassis centered in the middle of the long to where it just started to remove the weight from the the donuts. This was done to as an alternative to removing the doors and installing door braces.

I don't own a MIG welder, so TIG was my only best option, but I did quickly learn that TIG is not the right tool for this operation. Torch in one hand, rod in the other, operate pedal with knee, and contort body in ways never before experienced is just not the way to go. I was careful with my weld sequence to best manage heat build-up. Since I had no door braces, I worked slowly, and stopping often to check the door gaps. I would switch back and forth from the drivers side long to the passenger side long to again, manage the heat. I did this over a span of three days to insure that the door gap shrinkage was minimized. I did tack the rear cross re-enforcement in a couple of spots to hold it in place until the longs were done, then I finished welding that in place. When done with all the welding, I of course ground the welds flush.