October '17

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OCTOBER 2017 PRECISION ENGINE 11 PRECISION ENGINE an LS engine (converting to carburetion or replacing the factory intake and fuel injection with an aftermarket system), the factory plumbing system either can't be used or, even if it can be used, looks just plain ugly. Many builders choose to simply plug the steam ports in order to simplify mat- ters, but as noted earlier, this is a bad idea. There's a simple and effective way to accomplish the coolant plumbing while attaining more of a performance appearance at the same time. As an example, I recently built a custom engine that featured an after- market block (World Products Motown II LS block that accepts LS heads), along with a pair of Trick Flow LS heads. In order to properly evacuate air from the LS-style cylinder heads, I installed a –4 AN coolant transfer plumbing system to the cylinder heads, tying the front and rear cylinder head steam holes together to avoid potential overheating at the rear cylinders. In this particular build, the –4 AN plumbing system terminates at a Moroso water neck that we installed at the front of the engine. This allows the coolant that runs from the heads to bleed off and cir- culate into the radiator. Depending on the specific configuration of your build, the plumbing can terminate into a thermostat housing, water neck or to the radiator itself (by means of a threaded bung that can be welded or brazed to the upper radiator neck). There's no reason to be intimidated in regard to creating this custom steam plumbing. It's actually very easy. It involves a selection of –4 AN fittings and hoses ends and a length of –4 hose. If you've never assembled –AN hose ends before, it's no big deal. We'll explain the task later in this article. make sure that the base of the fitting block mates flush with the machined surface of the head when installed. Lightly wiggle the fitting while pushing down to fully seat the O-ring shoulder. Front view. A crossover hose connects the left to right heads, and a hose from a T- fitting connects the circuit to our water neck. This view shows our left front. A TFS steam plug with a –4 fitting is installed to the head. Connected to this is a female-female 90-degree coupler. Connected to the coupler is a T- fitting that features three male –4 connections that accepts the left-to-right front hose fitted with a straight hose end and a 90-degree hose end on the hose that runs to the water neck. ITEMS REQUIRED The setup I created involves the fol- lowing components. In this example, I chose Fragola plumbing items, but feel free to use your brand of choice. 4 Trick Flow TFS-30600611 steam plug fittings (featuring –4 male nipples) 4 Fragola 109004-BL 9O-deg hose ends, -4 5 Fragola 220104-BL straight hose ends, -4 36.25" Fragola 840604 black –4 hose, 6 feet. (The 6-foot length allows extra length if you make a mistake when cutting) 2 Fragola 498302-BL T-fittings, male/male/female, -4 1 Fragola 482404-BL T-fitting, male, -4 1 Fragola 496321-BL 90-deg female/female coupler, -4 1 Fragola 481605-BL straight fitting, -4 male to 1/4" NPT 2 Fragola 498202-BL T-fittings, male/male/female, -4 COMPONENT LOCATIONS In the example shown in this article, the steam plumbing layout was performed as follows. (Note that we refer to the right side as the passenger side, and the left side as the driver's side). A Trick Flow TFS-30600611 fitting was installed at each end of each cylinder head. Each fitting features a –4 AN male fit- ting. A 6mm x 1.0 socket head cap screw secures the fitting to the head. A short shoulder, fitting with an O-ring, inserts into the coolant port hole in the head's threaded hole. Be sure to lightly lube the O-ring and A view of our right front assembly. Con- nected to the TFS steam plug is a male/ male/female T-fitting. A female connects to the steam plug male. The upper male of the T accepts the 90-degree hose end that runs from the front to rear of the right-side head. The horizontal male of the T ac- cepts the front left-to-right crossover hose straight hose end. Rear view. A 90-degree hose end at the left rear steam plug routes the rear cross- over hose to a male/male/female T-fitting at the right rear. Because this example build has a distributor (small-block Chevy block equipped with LS heads), we curved the rear crossover hose for clearance with an 8-inch hose. On an LS engine block, this hose can be slightly shorter to obtain a straight hose run. Regardless of the application, this steam plumbing setup works on all LS cylinder heads.

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