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]

Thanks for all the nice words!

A couple more comments on the trailing arms. Welded structures are subject to movement due mostly to shrinkage from heat. As such, I did get some movement here and there, but the most significant area was the pivot shaft tube. Basically it was no longer straight, so I had to subsequently heat and bend it until it was straight. Also, the bearing bore diameter, to my surprise, shrunk a small amount which I didn't expect since the weld was what I thought was an adequate distance. Now we're talking about tenth's of a thousanth of an inch, but this is a press fit and needs to stay within a suitable range. In the end, the correct final step after welding, would have been to normalize or stress relieve the structure, but that would have added cost, time, and required an alignment fixture....too much added hassle so I didn't do it.

The overall weight of this custom piece is about the same as a stock trailing arm with reinforcement kit, so I think that worked out well. I had considered, and even started machining parts to make an aluminum trailing arm, but the risk just wasn't worth it.......A welded aluminum structure requires a multi step treatment cycle to relieve stresses, normalize, anneal, and heat treat. And in the end, it's still suseptable to sudden fatigue failure. I added a photo of the aluminum bearing carriers that I didn't use.

The parking brake is a Wilwood mechanical spot caliper, and I configured the linkage such that the stock 914 parking brake cable and clevis setup could be used without modification. The Wilwood caliper is a floating type which means it sits loosely in it's mount. The result is that it rattles when driving the car; very annoying! What I may do, is design some type of slide cofiguration (pins and bushings) to eliminate the rattle.

So the big unanswered question surely on everyone's mind, is why blue? Had a can of Ford engine enamel.......and now that they're on the car, the color looks kinda cool actually.

I threw in a photo of the stock trailing arm in the weld fixture.