Modern Engine Blueprinting Techniques. Mike Mavrigian

       In order to relocate the oil filter to a remote location, a base adapter is installed to the block at the original filter boss. Using either –AN fittings or nipple fittings at this base, you can then run hoses to the remote filter adapter. Bases are usually marked for inlet and outlet locations. At the engine block base adapter, “IN” is for oil flowing from the filter to the block, while “OUT” is for oil flowing from the block to the filter.

       Remote engine oil coolers provide heat dissipation for engine oil. Similar in function to a cooling-system’s radiator, an oil cooler serves as a heat exchanger, dropping oil temperature before oil returns to the block. In the event of an engine failure, where debris has flowed through the oil system, hoses and coolers may be very difficult to clean and difficult to verify as clean. If you scatter an engine, roach a few bearings, etc. do not place the existing cooler back into service. You’re better off replacing the hoses and cooler to eliminate the possibility of circulating trapped metal particles back into the fresh engine.

      Oil Pump Service

      Any metal or foreign debris that enters the oiling system and travels through the engine leads to failure. You need to service a dry sump system during the rebuild process. This includes disassembling, cleaning, and inspecting the oil pump for damage.

      You can plumb in-line filters in the oil return lines during system installation and the filters provide important protection. However, don’t rely on the filter alone. Always inspect the pump.

      A thorough cleaning of the system is necessary and many people often overlook this.

      Flush all the hoses, especially if you’re using hoses that you can’t also visually inspect, such as a long hose or a hose fitted with angled hose ends. Often, the best approach is to simply replace the hoses because debris can stick to hoses’ inner walls. If you’re certain that the hose is clean, by all means feel free to reuse it. If you have any doubts, though, spend the money to replace it.

       When servicing –AN plumbing, disconnecting an oil hose can result in a mess. Quick-connect fittings, originally designed for aircraft and racecar applications, are available. This is a coupler from Jiffy-Tite. The coupler is similar to that found on a compressed-air hose. Pull the collar back to release, and pull the collar back when connecting. The nice thing about these fittings is that they self-seal when disconnected, which eliminates an oily mess during servicing. They also allow quick and easy plumbing removal or installation without wrenches.

External Oil Coolers

      As you well know, engine oil lubricates the engine. But oil also absorbs heat from critical engine components and carries it away. The more available oil in the system, the more heat that can be absorbed. External oil coolers function as heat exchangers. The extra amount of oil in the cooler and cooler hoses adds more volume to the system. As oil circulates from the engine through the cooler and back to the engine more heat is released. This sends cooler and more viscous oil back into the engine. External oil coolers are generally plumbed with –10 AN hoses, which is equivalent to a 5/8-inch-inside-diameter hose.

      The cooler must be clean. If metal debris has entered the cooler, you can’t risk using it again because you can’t be certain it’s completely clean. It’s not worth risking engine failure to use a contaminated cooler. Simply buy a new cooler.

Oil Restrictors

      Adequate oil always needs to be delivered to the rod and main bearings. In some engines, restricting the oil delivered to non-critical areas improves oil delivery to vital components. For instance, in old Pontiac 455 engines, the factory oil holes in the lifter bores are larger than necessary so they steal some oil going to the main bearings.

      When these lifters bores are bushed in order to resize the bores, a smaller oil hole is drilled into the lifter bore liners. This intersects with the original oil holes but reduces the passage to around .040 inch. This provides enough oil for the lifters, while sending more oil through the main gallery to the main bearings.

      Certain aftermarket blocks have “priority main oiling” where oil feed passages are dedicated to the main bearings without bleed-off to other areas, so the mains get all of the oil they need. In some blocks, the lifter oil passages running from the rear are plugged by the factory. That means when these passages are initially drilled, they’re drilled all the way through and then plugged at the ends.

      Oil delivery to the distributor gear can be improved. You drill a small hole (about .020 inch or so) in the plug in-line with the distributor to provide a small amount of “dribble” lube.

       A distributor-driven, wet-sump oil pump requires an intermediate shaft. Be sure to install the shaft through the bottom of the block (in the oil pump shaft bore) before installing the pump. A built-in stopper, which can be a diameter change on the shaft, stopper bumps on the shaft, or a metal clip on the shaft, prevents the shaft from exiting through the top of the block. Make sure you lubricate the intermediate shaft before installation.

       Depending on application, oil may need to be restricted to reduce oil delivered to the top end to send more to the bottom end. Or an area that is normally blocked off may need a small bit of lubrication. Here a 3/8-inch NPT plug installed at the rear of the lifter galley in a Pontiac big-block is drilled with a .020-inch orifice to feed a bit of extra oil to the distributor gear.

      Each block design has different possibilities and requirements.