April '20

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32 THE SHOP APRIL 2020 BUILDING THE Nighthawk II LS PRECISION ENGINE A coil wire jumper harness from CBM connects the coils to the MSD ignition control harness. While the AFR spec sheet listed the use of NGK TR55 spark plugs, those plugs feature a taper seat, while the heads require flat gasket-style plugs. I spoke with AFR, which recommended using Autolite 3924 plugs. I gapped them at 0.045 inches and connected the plugs to the coils with MSD ready-fit 8mm plug wires (with a dab of dielectric grease in all boots). IGNITION CONTROL In the past, MSD offered two different controllers for 24-tooth or 58-tooth crank reluctor applications. The new controller, P/N 6014, accommodates either (separate sub-harnesses are included, and connectors are color-coded for either tooth count). The new unit offers a dizzying array of features including pre-programmed timing tables, rotor-select timing changes on the fly, high-speed data acquisition, pro- grammed step retard, launch and max rev limiters, launch retard, idle timing control and individual cylinder timing. You can run the basic setup (choosing from several programs) with no laptop required, or you can plug in via the supplied USB cable and customize as desired. A complete wiring harness and thumb- drive software are included. Note that a separate coil jumper harness is required in order to connect the ignition controller to the coil packs. We obtained our coil harness from CBM. This harness plugs directly into each bank of coils and allows connection to the MSD harness. Note that when using the new MSD 6014 ignition controller, the supplied wiring harness requires plugging the MSD harness directly into the front-mounted camshaft position sensor. The OE pigtail harness is not needed. This is a nice feature, since some OEM pigtail harnesses differ and can pose wiring compatibility issues. INTAKE SYSTEM Our induction setup includes a Holley 300-131BK single-plane intake manifold and the newly introduced Holley Sniper throttle body EFI. The intake manifold is secured to the heads with 10 6mm x 1.0 bolts—four at 90mm length (ARP 770-1014) and six at 50mm length (ARP 770- 1007)—all torqued to 106 pound-inches. Sealing is handled via O-rings that are supplied with the manifold, which seat into CNC-ed grooves around the perimeter of each intake manifold port. These are installed lubed with a light coating of Vaseline, which eases installation and won't harm the O-ring rubber. The EFI unit features wire harness con- nectors for the water temperature sender, O2 sensor, battery switch and ignition It's time to put the finishing touches on our Nighthawk II LS build and then visit the dyno to see how we did. Holley's relatively recent introduction of tall LS valve covers provides clearance for fat aftermar- ket rockers without the need for spacers. Coil pack installation is simplified by allowing direct coil-to-valve-cover mounting, eliminating the need for ugly OE coil brackets. The coil stand- offs are spaced 72mm apart, a direct match for our MSD coils. The valve covers include aluminum standoffs and upper grommets, so no cannibalizing of OE parts is needed. Our MSD coils, P/N 82878, are secured to the valve covers with ARP 12-point stain- less screws. The pre-assembled MSD plug wires provide out-of-the-box installation. Holley's new Sniper EFI provides the efficiency of central fuel injection. Designed to fit a 4150 manifold flange, the unit is self-contained, featuring a built-in throttle body ECU, internal fuel pressure regulator (preset to 58.5 psi), integrated ignition timing control and coil driver, built-in fuel injectors and throttle position sensor. The unit is self-tuning but can be adjusted via the cockpit-mounted color touchscreen display. It is rated to handle 650-plus hp.

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