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]

As promised, here's what I did with the radiator water management and piping. I wanted to design a system with the correct elements necessary to ensure good performance. My main focus was on a system that would separate air from the water, and to reduce or remove the possibility of trapping air pockets. To start with, the LS1 motor has 4 steam vents in the heads; the early LS1/LS6 plumbed all four into the top of the radiator, and the later ones use only the front 2 steam vents. The traditional front engined layout tips the motor slightly back so 2 steam vents would be ok, but the 914 layout has the motor sitting level, thus I chose to use all 4 steam vents. Wegner Automotive sells a nice steam vent adapter that has a 1/8 NPT f'male thread complete with o-ring and stainless screw for cheap. I installed those, and used 90 degree compression fittings for 1/8" tubing. I decided to try some 1/8" nylon hard line as it is small and easy to route. You'll see how I ran those to my header/air separator tank.

I fabricated an aluminum flow-thru header/air separator tank, and mounted it on the drivers side of the engine compartment. I also fabricated a small purge tank. With this location, I needed to run a line from the right side water pump outlet under the motor to the left side. I made a stainless crossover pipe; I got some stainless 90 degree elbows from McMaster-Carr and welded them in, then mounted it to the motor mount bar with Adel clamps.

I decided to make under car hard lines. I first made a pattern using EMT and EMT bender so that the pipes run in the two depressions in the floor pan. This helped me a lot when making bends in a heavier walled steel tube. I went with mild steel here because it's easy to bend, where stainless thin wall is nearly impossible. After bending, I coated the inside of the steel tubes with POR-15. I did weld thin wall stainless tube ends with hose beads on each end. I attached photos of a beading tool I made and the resultant bead.

I cut a hole in the lower trunk area for the piping to pass through. What I did find was that the 911 aluminum suspension cross member was too bulky, so I used the tubular stock 914 cross member instead.....it was a tight fit. I've got some photos of the under car piping, but can't seem to find them at the moment; maybe later? Anyway, I hope the photos show enough to make sense of it all.