Cylinder Honing Tools for Rebuilding Diesel Engines

The International 7.3L IDI is an eight-cylinder, indirect injection (IDI) diesel engine used in Ford F-Series pickups, Ford E-Series vans, school buses, and commercial  vehicles. As the successor to the 6.9L version of an International Harvester (now Navistar International) engine, the 442-cubic inch 7.3L IDI featured a cast iron block and heads plus bigger bores and larger-diameter pistons. Ford also offered truck buyers a factory turbocharger option, but naturally-aspirated 7.3L engines continued to sell into the 1990s.

Diesel Power and Engine Rebuilds

Today, Diesel Power magazine provides diesel mechanics and automotive enthusiasts with examples of engine rebuilds. As the world’s largest diesel magazine explains, engine hones from Brush Research Manufacturing (BRM) impart an ideal surface finish to cylinder walls. Self-centering, self-aligning to the bore, and self-compensating for wear, the BRM Flex-Hone® tool produces a plateau finish that optimizes engine lubrication and promotes proper piston ring seating and sealing.

In an article entitled Rebuilding International’s 7.3L IDI Engine Heads and Crank, Diesel Power magazine shared the story of how cylinder honing tools helped restore a used IDI engine. As the author explained, only one of the eight cylinders had “some surface rust” with the other seven free of “major scratches or blemishes”. While a machine shop polished the crankshaft, resurfaced the heads, and performed a valve job, the engine rebuilder deglazed and surface finished the cylinder walls.

Flexible Honing and Cylinder Deglazing

When engine cylinders are manufactured, their walls or liners are honed to create a series of grooves or “scratches” that promote oil retention. During engine break-in, the reciprocating movement of pistons removes high spots, leaving a uniform series of ridges. Over time, however, the pistons’ up-and-down movement polishes the cylinder with a glaze that prevents oil from adhering properly. Left unbroken, this polish or glaze can cause problems with friction and lubrication.

To break the glaze and improve cylinder wall surface finish, engine mechanics like the author from Diesel Power mount glaze breaker hones in a handheld electric hand drill. With a BRM cylinder hone generously lubricated (preferably with Flex-Hone® oil) and spinning at the recommended RPMs, users stroke the cylinder according to recommendations in the Flex-Hone® Resource Guide.

Cylinder Cleaning and Product Selection

When engine honing is complete, experienced Flex-Hone® customers like Caterpillar use hot or warm soapy water for cleanup. As a supplier of a full line of industrial brushes, BRM also offers cylinder wash brushes made of 6-12 Nylon in diameters ranging from 3.5-in to 6.5-in. After cleaning leftover dust and debris from the engine block, engine builders should lubricate metal surfaces.

In addition to cylinder honing tools, Flex-Hone® oil, and cylinder wash brushes, Brush Research Manufacturing (BRM) supplies diesel mechanics and do-it-yourself (DYI) engine builders with injector brushes, seat cleaning brushes, plunger bore cleaners, and O-ring groove cleaners. Visit the BRM website for information about BRM brush tools, including brush technology designed especially for use with Caterpillar, Cummins Group, and Detroit Diesel engines.