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How to Cover the LS Wiring Harness

Clean And Simple: Fabricating covers for the LS coil and injector wiring

Gerry Burger Aug 11, 2016 0 Comment(s)
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There is no doubt the Chevrolet LS series small-block is the most popular modern engine within the hot rod community. When it comes to engine swaps, the venerable small-block Chevy package simply seems to fit everything, and that includes every rendition of the engine from 1955 to our present day offerings.

The LS series of engines have proved to be perfect candidates for Corvettes of any year. They are compact and because of the direct port fuel injection, the top plenum is very low. A group of very cool-looking runners route air into the cylinders. This eliminates any problems with hood clearance, something that is always a concern when swapping an engine into a Corvette. As for power, the only limits seem to be your wallet and your desires.

While virtually every aspect of the engine has improved with each new iteration, one aspect that has fallen short is the aesthetics. In its natural habitat (i.e., under the hood of a new car) the manufacturer relies on plastic cover(s) to make a presentation to the potential buyer. Of course, that will never do for anyone modifying a Corvette with an LS powerplant.

There are any number of ways to dress-up a modern LS engine, from complete camouflage kits that make the LS engine look remarkably close to a vintage small-block to simple coil covers with early-style valve cover flavor.

But for many people they want to embrace the modern look of the engine but also want a super-clean installation. That was the approach TEN Tech Center Manager Jason Scudellari took when he was cleaning up his stroked, 383-inch LS3 engine. The engine had already been modified with a FAST XFI Sportsman fuel-injection system that is force fed with a Torqstorm supercharger. Obviously there will be no shortage of power with dyno numbers like 560 hp and 555 lb-ft of torque at the rear wheels. While this engine is not in a Corvette, the aesthetic improvements will work on any LS.

When it came time to “clean things up,” Jason took a very straightforward approach. The FAST XFI Sportsman unit has a great performance vibe so he certainly had no desire to hide that under a cover. Ditto the Torqstorm supercharger and associated ducting. But the one thing all modern engines have a problem with is what is best described as clutter. After all, there is a lot going on with electronic controls and sensors everywhere. The trick Jason faced was how to make the engine look clean and a bit simpler without losing the modern performance vibe that would be perfect under the hood of any generation Corvette.

Step one was replacing the factory coils with PerTronix Flame-Thrower coils. These are direct replacement pieces using the factory harness and connectors. The factory wiring harness puts the harness plug right in the middle of the valve cover, making the wiring pretty unsightly. Just above the coils you’ll find four injectors per side and yet another wiring harness. Jason figured if he could just hide the wiring harnesses the rest of the pieces would bring out the cool, modern-performance appeal he was going for.

After studying the problem for a while he realized he should start by relocating the factory center plug to the rear of the harness so the wiring harness would lay flat in the valley between the valve cover and the intake. That was a simple matter of cutting the factory harness, relocating the plug to the end and then reassembling the wiring harness with solder and shrink wrap connections. When you are modifying a harness such as this it pays to label everything, mark wires and take plenty of digital photographs so you know for sure where the wires belong. That said, it is a pretty straightforward electrical project as long as you—as always—take your time and make perfect connections.

With the wiring done it was time to form a simple cover to hide the wires and at the same time become a nice transition piece from the FAST intake to the valve covers. As it turns out this, too, was a very straightforward sheetmetal project. The sheetmetal was cut and a slight radius was formed over a piece of 3-inch pipe. Then the Eastwood metal brake made a nice, larger-than-90-degree bend. Four reliefs were cut in each panel to allow the wiring harness to connect to the coils. End panels were cut, fitted and MIG welded to the top panels finishing the piece. Only one problem remained, how to attach these panels to the engine.

Jason decided to drill and tap the lower portion of the FAST fuel rail as that is solid aluminum. The proper drill size was employed and then tapped for 10-32 threads. Two socket head cap bolts per side would locate the panels, but here’s the cool part. A simple rubber grommet was sourced from the Harbor Freight grommet selection box and slipped over the 10-32 socket head cap bolts before threading it into the fuel rail. Then the new steel panels simply slip into the groove in the grommets, holding the panels firmly in place with no vibrations transmitted from the engine. Slip them on, slip them off.

When all the fabrication was complete a couple coats of chassis black provided the perfect satin finish. The end result is a transition panel that simply made a lot of that LS clutter disappear. The good news is this is well within the reach of any backyard mechanic with some reasonable time, skill and tools. Follow along with the photos and we’ll show you step by step how to complete the project.

2 Bandsaw 2/27

01. Starting with a simple sheet of 16-gauge steel, we cut out our blanks on a bandsaw. The cuts could also be made with a sheetmetal shear for those without a bandsaw.

3 Sheetmetal 3/27

02. After putting a slight radius on the sheetmetal by bending it carefully over a piece of 3-inch pipe, Jason made a radius gauge from a piece of poster board so both covers would carry the same radius.

4 Eastwood Metal Brake 4/27

03. Satisfied with the radius, we scribed a line with a Sharpie and then put the sheetmetal in the Eastwood metal brake and bent the piece past 90-degrees.

5 Sheetmetal Brake 5/27

04. This is the final brake on the sheetmetal. The folded down tab will serve as a mounting surface for the cover.

6 Engine Cover 6/27

05. The cover is placed on the engine up against the fuel rail so the location of the coil wires could be marked for cutting.

7 Drilled Four Holes 7/27

06. To form the slots, four holes are drilled into the panel at the designated points. Support the sheetmetal when drilling to prevent bending.

8 Bandsaw Sheetmetal 8/27

07. A quick trip to the bandsaw makes short work of cutting the sheetmetal into the holes we just drilled.

9 Sheetmetal Rounded Corners 9/27

08. A bit of work with a fine file produces smooth openings with gently rounded corners. Be certain there are no sharp corners or edges that could possibly cut a wire.

10 Chevrolet Engine Panel 10/27

09. Once again, the panel is placed on the engine and a poster board template is cut for the end plate.

11 Sheetmetal End Panels 11/27

10. The end plates are cut from the same piece of sheetmetal as the panels. Cut both end plates and make them identical. This will ensure that both end plates are exactly the same shape and radius.

12 Miller Mig Welder 12/27

11. Jason fires up the Miller MIG welder and welds the end plate to the cover.

13 60 Grit Rolec Disc 13/27

12. A little metal finishing with a 60-grit Roloc disc on an air grinder and the end plate and cover now appear to be one seamless piece.

14 Chevrolet Engine Fast Fuel Rail 14/27

13. To fasten the cover to the engine Jason carefully drills two holes in the lower portion of the FAST fuel rail. Be certain to keep the hole below the actual fuel port in the rail.

15 Chevrolet Ls Engine Tap Sockets 15/27

14. The hole is tapped for 10-32 threads using a socket designed for taps. A set of tap sockets should be in every toolbox. Use of a bottom tap will provide deeper threads.

16 Sheetmetal Boltholes 16/27

15. Jason carefully marked the location of the two 10-32 boltholes and formed a pair of slots in the sheetmetal panels using the same technique we outlined earlier.

17 Grommet 17/27

16. Now this is one slick trick. To attach the sheetmetal panels, a pair of 10-32 socket head cap bolts and washers hold a simple grommet in place on the fuel rail. Snug, but do not over tighten the bolt.

18 Socket Head Cap Bolt 18/27

17. Here we can see the socket head cap bolt threaded into the fuel rail. Note the injectors and associated wiring on either side of the bolt, that’s what we want to hide.

19 Chevrolet Ls Engine Fit Panel 19/27

18. Now it is time to test-fit the panel. If you did everything right the cover should slide into the slots of the rubber grommets and be held firmly in place.

20 Chevrolet Ls Engine Pertronix Flame Thrower Units 20/27

19. And there it is, the metal-finished cover in place. Notice that we have changed the stock coils over to new PerTonix Flame-Thrower units.

21 Stock Factory Harness 21/27

20. The top harness is the stock factory harness with the connector plug in the middle of the harness. The lower harness is the modified harness with the plug relocated to the rear.

22 Modifying Factory Harness 22/27

21. Modifying the factory harness begins by cutting the center connector free from the harness. Take notes, take digital photos and mark down where the wires go prior to cutting the wires.

23 Center Plug Factory Harness 23/27

22. The center plug is on top and the location and color of each coil plug is marked on the workbench to prevent mixing up any of the wires.

24 Cutting Wire 24/27

23. Slowly and carefully, each wire is cut, stripped and soldered in place. Note a piece of heat shrink wrap has been slipped over the wire prior to soldering.

25 Solder Joint 25/27

24. Keep the heat shrink wrap away from the joint during soldering. Then, once the solder has cooled slide the heat shrink wrap over the solder joint and shrink it with a heat gun.

26 Electrical Tape Harness 26/27

25. Some electrical tape holds everything into one tidy harness. As you can see, the main coil plug will now be at the rear of the engine. Notice how the harness now lays nice and flat.

27 Chevrolet Ls Engine Wire Covers 27/27

26. After a little priming, sanding and painting with Eastwood Satin Black, the new wire covers blend in perfectly with the LS3 engine and the FAST fuel injection. The end result is a neat engine that still exudes the look of modern performance.

Sources

PerTronix Performance Products
San Dimas, CA 91773
909-599-5955
pertronix.com
FAST
Memphis, TN 38118
901-260-3278
http://www.fuelairspark.com
Harbor Freight Tools
800-423-2567
www.HarborFreight.com
Miller Welding
www.millerwelds.com
TorqStorm
Wyoming, MI 49548
616-706-5580
www.torqstorm.com

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