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]

Here's how I did my shift linkage. I know that from time-to-time some have posted cable shifter ideas for the 901/915/Subie/etc. Here's how I did my Audi 01e 6 speed.

I did try at first to prototype a rod linkage, but the resultant angles were just not condusive to good action as the Audi shift shaft is oriented transversely and is high on the housing, so I gave that up pretty quickly.

So on to a cable shifter solution, I first thought about designing a cabin shifter to suit all my needs. I quickly found that OEM shifters had nearly all the features I needed, so I went that way instead of designing and fabricating my own. I decided to go with a Toyota shifter. There are others, but I figured the Toyota would be the easiest to find. I didn't consider the Boxster shifter, as it's plastic construction doesn't lend itself well to modification. So off to the local Pick-and-Pull and I struck gold. I found MR2, '90's Celica, and '88 Tercel shifters....I also found a Mitsubishi shifter, but I figured the three Toyota shifters would be plenty enough to choose from. The MR2 shifter was nearly plug-and-play, however it didn't have quite enough gate travel for 3 gates plus the reverse gate for a 6 speed application. Just a quick note; the MR2 shifter in a nice piece for those looking to do a 5 speed shifter. The Tercel shifter was reall quite nice as well, but also suffered from a lack of gate travel. I settled on the Celica shifter mostly beacuse of the ease by which the gate limit stops could be modified. I re-configured the shifter base so that it would mount to the existing 914 shifter bolt pattern, though I did move the shift lever position back about 1 1/2" as the stock 914 position was just a bit of a stretch for me. Also, I wanted to keep the shifter low enough for a subsequent console, so I re-configured the cable bulkheads to maintain a low profile. Because there are so many gates on a 6 speed, I wanted to employ a reverse lock-out. I did this by sliding a thin wall tube over the shift lever that is actuated by a finger flange under the shift knob with a spring to keep it in the down position. At the bottom of the tube, I welded a tab that when in the down position, obstructs the shifter from entering the reverse gate.

On the transaxle, I set out to design the correct lever ratios to match the travel of the shifter, and to translate the motions for the correct directions necessary. I needed a bellcrank to reverse the gate action, so I went down to my favorite aircraft surplus store, Lucky's Hardware, in Burbank, CA (a great place!) and found a circular flange mounted to a duplex bearing used for small aircraft control systems; $4 each, so I bought 2 of them. I designed and fabricated the linkages, levers, bulkheads, and zinc plated everything.

To get the exact push-pull cable lengths required, I had a coil of high pressure nylon brake line left over from my old GoKart racing days, which I fed through the firewall, to the shifter, and marked. I ordered my push-pull cable from CableCraft, who I've been using for years. A phone call to their tech guy, custom length, any bulkhead, any end, any travel, a credit card, and it's in the mail within a couple of days. Great company to work with!

Hope the attached photos are adequate to show what I did....ask if you have any questions.