To those who are familiar with the Optispark and to those who know it only by reputation, it should be no surprise when I say it is a particularly fickle contraption. Brand-new units have been known to fail. Some have been fixed with a few hammer taps, while others work like a Swiss watch. There seems to be no rhyme or reason to it, leading me to believe that some other forces are at work here. Maybe it's supernatural, voodoo, or whatever you want to call it... or maybe these things are manufactured at the same plant that made the WWII German Luger handguns.
If you caught the last installment of our LT1 Formula build, then you know an Opti swap and a high-output coil upgrade were intended to complete our bolt-on install. Unfortunately, replacing the Opti did not go as smoothly as we had hoped as two separate Opti replacements we tried failed to provide a low-resolution signal to the computer-vastly throwing askew the ignition timing. The Formula would neither idle nor rev properly, and in a last ditch effort Ron's Custom Auto Head Technician Junior Perez threw the stocker back on and voila! The LT1 came back to life. Though we both knew this was only a temporary fix in order to get to the dyno and the track before getting another fresh replacement, we had no idea that the crusty stocker would start to misfire under load. After putting out a power curve that looked more like a polygraph than a dyno sheet, it was back to the drawing board.
Instead of trying to replace the Opti again, we tried a shortcut that wouldn't just Band-Aid the flawed distributor, but would almost negate its use altogether. The solution to the Formula's ignition problems was presumed to be the LTCC LS1 individual coil swap. In using this particular engineering marvel, the Opti is used only for an optical signal-while eight individual LS1 coils provide the spark itself. Given our affection for MSD's quality components, we choose its high-output MSC Blaster Coils (PN 82458) in lieu of scrounging for a set of stockers. Either way, though, the Formula would be light-years ahead of the stock setup. Since the LTCC kit consists of basically just the adapter wiring harness and ignition box, some sort of mounting brackets would have to be fabricated as well as custom-length plug wires. Thunder Racing had just the cure-the LS1 Coil Relocation Kit (PN COILRELOKIT), which comes with mounting brackets and Cut-to-Fit Taylor wires. This kit is designed for LS1 cars, so that the coils can be taken off the valve covers and mounted just under the cowl for easier access to the valvetrain and headers as well as a cleaner look. Some complications were anticipated as the LT1 might cause some clearance issues due to its difference in dimensions and layout of hoses, wires, etc. But it was worth a shot in order to have a cleaner install and save some time.
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Picking up where we left off in our last installment: Ron's Custom Auto technician Junior Perez attempted to replace our crusty stock Optispark distributor with a fresh unit before installing the March underdrive crank pulley. Unfortunately, both the first and second attempt yielded a lack of low-resolution signal leading from the Opti to the factory wiring harness, as indicated by a scan tool. This caused an idling and revving problem best described as spitting and popping, as if the ignition timing had been thrown off. Since by this point we had changed a number of parts already, Junior put the stocker back on to make sure it was in fact the replacement distributors we had used and not something else we had changed. When it fired up and appeared to be running tip-top,... | 
...I decided to leave well enough alone and button up the rest of the install. After Junior removed the crank snout from the stock crank pulley via a 20-ton press, it was reinstalled onto the crank with the installer tool. The March pulley was then bolted down with a 5/8-inch socket, Loctite, and 60-80 ft-lbs of torque. In case you are wondering about the plug wires, Junior went to great lengths to make sure they were plenty guarded (with Accel heat sleeves) from the scorching hot header primaries. Since these will have to come off the car anyway, we are going to skip over this. |