Part 11: Ol' Sparky Retires - Ignition UpgradesWritten by on July 1, 2003 Ignition Upgrades With the Help of Crane Cams
Last month, we showed the install of our hidden nitrous-oxide kit in the Valiant. We may be dumb, but we aren't completely stupid--hitting the giggle-juice button with the stock points ignition would surely cause a problem. Point-breaker-style ignitions simply send the current to the correct cylinder as determined by the cam on the distributor shaft. The limiting factor is the voltage that the points are able to carry without fusing themselves shut. To burn the extra fuel and nitrous, we needed more spark than the points could safely deliver.
To solve this dilemma, we contacted Crane Cams--yes, we said Crane Cams. Crane has long been known for their quality cams and valvetrain parts, and since they developed an ignition called the FireBall system, we decided to give it a try. This capacitive discharge (CD) ignition will, under low-rpm starting conditions, generate up to 12 sparks. At idle and cruise rpm, the number of sparks fired is adjusted to maintain a total spark duration of approximately 20 degrees of crankshaft rotation. Above 3,000 rpm, the CD unit generates a single powerful spark. We decided on the HI-6 unit, which has a sequential rev-limiting circuit for staging, timing retard capability (with optional TRC-2 controller), and system diagnostics. In addition, even though Crane Cams recommends its LX-92 coil, most OE coils are compatible.
To ensure everything was up to par, we added Crane's LX-92 coil, XR-700 optically-triggered points conversion, and a set of its new FireWire plug wires. Usually when we do a conversion like this, the inevitable problem arises--it will not run, even though you know you followed the instructions. The installation of the Crane ignition system literally took less than a day. The nicest part was the initial fire-up. The engine made about three revolutions and was purring like a kitten... OK, we'd like to think of it as a large cat, but nonetheless...
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The first thing we did was decide where to mount the HI-6 box. We chosethis spot directly behind the core support because there was an openingin the support that allowed air to pass over the box. It also helpedthat all the wires reached the areas where they needed to go. The largered wire was connected to a 12-volt, switched power source, and thelarge black wire was grounded.We then mounted the coil to the firewall in a location close to thedistributor. Crane recommends the coil be mounted within 18 inches ofthe distributor. Also, the mounting bracket for the coil must begrounded. Since we were mounting it to the firewall, this was not anissue. If you mount the coil to a fiberglass, wood, or plastic mountingpoint, run a ground wire from the coil bracket to a grounding source.We ran the wires along the inner fender and up to the firewall. Thewires we weren't yet using (i.e., stage rpm limit input, timing retardinput, and engine cylinder selection--not used for eight-cylinderengines) were taped up and mounted under the box.The supplied coil input wires have preterminated ends that plug into thecoil. The other ends plug into the orange and black wires from the box.The HI-6 box comes with weatherproof connections, which, if removed,voids the warrantee. Install the included weatherproof connector to thewires from the coil, and simply plug it in.Before making connections or cutting wires, make sure you can route thewires out of the way, where they won't touch any hot engine parts oranything that may chafe or cut them. We ran ours along the edge of thefirewall and behind the wiper motor.If you're using a tachometer, connect the tach's pulse-input wire to thegreen wire coming from the ignition box. Again, use the suppliedweatherproof connectors.On to the distributor: We needed to install the optical sensor into thedistributor. The accessory kit for the optic comes with differentreluctor wheels and optic mounting brackets. Choose the ones that fityour application.
Next, we installed the appropriate reluctor and then slid the opticsensor onto the bracket and attached it with the supplied screws. We putthe wires from the optic through the hole in the distributor housingoriginally used for the points wire to the coil. The distributor wasthen completed--it was that easy.The red and white wires from the optic were connected to the same colorwires from the CD box. Again, we used the weatherproof connectors. Thered wire was also connected to a switched, 12-volt source (the oldcoil's power-supply wire). We connected the black wire to a goodgrounding source.