The Installation of an MSD 6AL and Twin Coils
We need a place to put the box. Here's a good spot. There's nothing in the way, and the air cleaner draws from this area. The unit draws as much current as a decent sized amplifier (15 amps!) so we need at least some airflow. This should be overkill. Plus, in this location, none of the wiring will have to be lengthened.
The first picture is a cardboard mockup of the MSD bracket. This is actually mockup #2, the first one was made of smaller pieces. Call this one the beta mockup. I wanted to utilise all factory mounting holes. The strut studs are perfect, and there is a hole drilled in the inner fender that is for God-knows-what, and was untapped. (Was.) I had to be careful of the air conditioning lines, the hood braces, and the "lip" on the edge of the strut tower. More on that later! The second picture is the bracket, cut out of some scrap steel sheet. I used an old computer case. You can often find 286s and 386s on trash day, and they cases on the older models are made of fairly heavy-gauge sheet with a second anti-RFI layer on the inside. Removal of the inner layer greatly speeds up the cutting process! Even so, I used up an entire 3" cutting wheel. I was also thinking of using a microwave's outer case, or the side of a washer or dryer. Lots of people throw away perfectly good sheet stock in the form of home appliances!
The first photo is a mock-up of the coil bracket. This one was a little tricker than I imagined. First I had to mount the coils into their brackets, then cut a piece of cardboard to rough size and pop it onto the strut studs, then hold them at a height that did not hit the A/C compressor yet also didn't interfere with the hood and close together enough that it wouldn't look ugly and take up tons of room. Then, I had to take my third hand and mark the bracket positions! I did cheat a little bit, though. The bracket's size was determined somewhat by the size of the computer case I used! The top part of the bracket was the side of the case, so that's as far away as it could extend. Fortunately, it well clears the fusible links and junk directly beneath it. I had to carefully slice away at the mockup until it cleared the (nonfunctional) cruise control unit on the one side, and the ignitor assembly on the other side.
Ignitor assembly?!? Yes, this was done on a 1980 model, the one year with remote ignitors. I thought the setup would have been perfect: Just clip the leading pickup's wires and connect them to the "direct input" leads on the MSD box, just as Paul Yaw recommends. However, the 1980 setup gets its tach signal from the *leading* side. This left me a dilemma: I could connect the MSD to the leading pickup, connect the leading-out wires to the trailing pickup, and connect the (old) leading coil to the trailing terminal on the distributor cap. This would give me full-time trailing spark (which 1980 did not have), use of the tach, and direct pickup to the MSD ignition.
Instead, I gave in and just wired it per the MSD instructions for "points ignition". Connect all the wires off of the coil - and connect to white wire, all wires off of coil + go to thin red wire. This is what Paul Yaw says NOT TO DO, but as of this writing I've put 2500 miles on the setup with no problems. (Car had 113,869mi at conversion, is 116,3xx right now) I will be doing it "properly" when I put my ported engine in, with its later integrated distributor. Other than that, installation was a pile of cake! Big Fat Red wire went straight to battery positive, Big Fat Ground went conveniently underneath
one of the strut nuts (cleaned the paint from the body, of course!), and coil+ and coil- wires were made from heavy-gauge speaker wire, which comes in convenient pairs.
Yes the rev-limiter works! With a 7000 "pill" in it, the engine runs a little "not smooth" and will NOT go over 7200, even out of gear! It doesn't "bounce" off of the limiter (whaaa-na-na-na), the engine just hangs there. I suppose the engine doesn't make enough power on the trailing plugs alone to go on! (Or is that the factory sometimes-they're-off strategy at work? Hmm.) I chose the 7000rpm pill instead of the 8000rpm pill because, quite frankly, it's fun to hit the limiter!
Here are some blurry shots of the finished installation, I promise I'll eventually replace them with better quality ones!
last modified 02/03/2001 10:14pm