Project BubbaZ Part 2: It Begins!
Posted at 8:49 PM / August 8, 2009
Continued from Part 1: Introduction Click Here
So, I've got these two cars and want to combine them.
I know that the front subframe on the Camaro is going to require some significant modifications, so I start by removing the front clip from the Camaro, and pulling the motor and transmission. I've done it a number of times in the past with parts cars, so it goes very quickly.
Next up, removing the motor from the GTO. This has to be one of the easiest cars around to pull the motor from. I didn't have to remove the hood – though I did disconnect the transmission first. The motor comes out easily through the top.
At this point I need to spend a little money. I order up a set of 2006 GTO factory manuals from Helm Inc ($150). I could not imagine doing a retrofit like this without the factory manual – it would be like flying blind. You just shouldn't do it. I also locate and purchase a used F-body oil pan, pickup tube, and windage tray ($200). The GTO oil pan is front-sump, which absolutely won't work with the Camaro subframe.
I also start asking around for a junk LS1 block - and it turns out that some fellow Texas-based Planet LSX members are looking to get rid of one, along with some junk heads. So we meet up and I now have a “motor” that weighs a lot less than a fully loaded LS2... perfect for all of the trial fitting that will be required. To match this, in the past I used to rebuild T56 transmissions – so I have an empty T56 shell just “laying around”. I bolt these parts together, along with the F-body oil pan, and I have a lightweight setup that I can use with no worries about damage.
The use of the GTO accessories has two major issues in the second gen Camaros. The air conditioning compressor location, and the alternator location. The A/C compressor will hit the subframe when you use an F-body oil pan, and it is a top/side discharge unit. The alternator hangs down low enough to interfere with pitman arm travel. If you raise the motor to clear the pitman arm, you will have to cut well in to the firewall in order to get the transmission to fit (along with the center-of-gravity issues). So the goal is to find the “sweet spot”, and make some compromises that you can live with.
The first step is to figure out where to put the motor mounts. The use of the F-body oil pan means that the motor will sit about 2”-3” further back than a small block Chevy. I cut some 1/4” plate vaguely based on this design:
LS1 Motor Mount Plate
I used the stock '79 small block 3-bolt mounts for test fitment.
As it turned out, I thought that this setup resulted in an engine that was sitting a little too high. With the subframe level, and the engine at a slight angle, I had to shim the transmission mount about an inch in order to fit properly. In addition, I had about 2 inches between the bottom of the oil pan and the subframe crossmember. It just looked too high.
So I decided to take the plates that I'd built, and turn them in to 'cup' mounts – to mimic the original 79Z factory block mounts. This had the effect of lowering the entire setup about 1 inch – and it looked perfect.
For the air conditioning compressor, I had to notch the subframe. I also milled the air conditioning bracket 1/8” in order to bring the compressor closer to the block. For the A/C lines, the lower connection is small tube (3/8” or so), and comes out at the bottom and goes forward. I plan to shorten the “bent” portion of the line and re-braze the fitting. For the upper connection, it is a much larger line, and will require both bending and brazing in order to fit.
For the steering system, I plan to use a drop pitman arm – a 2” drop should be sufficient. Here is a mockup with a Third Gen F-body pitman arm. Unfortunately this one will not work because the hole for the ball joint is too small, and there's not really enough material around the hole to allow me to open it up safely. This will change the bump steer characteristics of the steering system, so I will need to purchase some drop tie rod ends to match.
With the motor mounts now in place, I can bolt up the GTO transmission (no more shell), and see how well it fits in the transmission tunnel. Well, it turns out that it doesn't. It hits the top of the tunnel in multiple locations. So, I grab the plasma cutter, and the top of the tunnel disappears. I'll have to fix this later.
Now, on to the fun stuff!
Of course along the way, I have to test fit the turbos. Based on the previous “Sharpie” test, I knew that the passengers' side would not fit without cutting. However, the drivers' side does fit, and fits quite well. There's one little spot of interference for the vacuum/boost reference fitting, but other than that, the turbo fits perfectly. I am going to try to 'clock' the turbo so that the outlet is closer to a 3:30 exit (instead of its current 4:30 position).
Well, we hit our first real snag. I cut a nice chunk out of the passenger side subframe - and the turbo just won't work in this position. The inlet is pointing right in to the lower control arm mount. I need to turn the turbo.
So, I grab some 3/4" MDF and see if it's even possible to turn the turbo. I'm thinking that I can make a "shim" out of some metal using my mill. This does seem to work.
Unfortunately, I do not have any 3/4" plate on hand. I do have some 5/8" plate though, so I fab up a spacer and do a test fit. The spacer has countersunk allen head socket cap screws going up in to the manifold, and is tapped for studs for the turbo. One of the studs is 'common' between the manifold and the turbo. My benchtop mill got a real workout.
There's still more work to do on the subframe. We still need to fit the transmission crossmember, weld up the holes, grind the factory slop welds, and sandblast/paint. Stay tuned for the next installment!
