Gopher Engines

Here are some of the steps in rebuilding an engine that makes a Gopher engine superior quality. Old cores are dismantled down to bare castings. Castings are baked for 12 hours at 650 degrees. Smoke is consumed in afterburners to prevent any pollution.
Castings are then put into steel shot machines where any ash residue is removed. They come out looking brand new. The engine block is the foundation on which engine parts are assembled, so if the block isn't true, nothing else will be. The block is carefully inspected and magnafluxed.
Every bolt hole is cleaned and retapped. Then it is ready for machining. Block surfaces are milled NOT ground, as a milled method provides an ideal finish to assure proper head gasket sealing. All cylinders are chamfered to eliminate any sharp edges that may create hot spots. Then the cylinders are finish honed on the Sunnen Automatic Hone. This machine has many optional spindle and stroking speeds that, when coupled with proper grit stones, allows the machinist to hone the precise cylinder wall finish that will be compatible with the specific type piston ring being used. Each crankshaft is subjected to careful inspection also. We check for journal undersize, worn keyways, rear main seal wear and thread wear. Due to the intricate nature of crankshaft castings, examination is not left to the unaided eye. Castings are magnafluxed using a black light to detect any minute flaws. If a crankshaft is found that must be built up, a special process is used that includes normalizing the castings after repair. Normalizing consists of heat treating the crankshaft in a special oven at a temperature of 950 degrees for four hours. The castings are then gradually cooled. This lengthy process prevents any breakage problems. Gopher crankshafts, including the rear main seal areas are ground and knurled on the company's Italian built Berco Crankshaft Grinder, the best in the industry.
Knurling is the etching of fine line impressions on the seal area that allows the oil to work its way back into the crankcase and prevent any rear seal leaks.
All oil holes are then chamfered to prevent any cutting of bearings and to aid in oil distribution, thus a longer lasting engine. Cranks are then micropolished to a RA(rough average) 5 to 8. Sizes are verified, and the crank receives its final inspection to assure trouble free performance. Technicians carefully inspect each camshaft for straightness, center trueness, lobe wear, keyway wear, and gear wear. The company will not compromise quality by allowing any flawed components. All profiles are restored to new specifications on Berco Camshaft Machines. After machining each cam, Parker Lubrite is used to provide optimum oil retention for break-in protection. Every connecting rod is also carefully checked for integrity and straightness. The rods are then machined to exact specifications using electronic measuring devices. A unique heat induction process to hang pistons on the rods was developed by Gopher to prevent piston pin galling. To prevent the pins from scoring, pins are oiled prior to pin fitting.
After thermal cleaning, all cylinder head castings are carefully inspected and magnafluxed also. Cylinder head gasket surfaces are milled to assure a perfect seal.
Valve guides are drilled 10 thousandths of an inch oversize, using a Serdi Seat and Guide Machine, tops in the industry. The air ride mechanism floats to the proper position and then machines a perfect 3 angle seat within a matter of seconds. This method is not only faster and cleaner, but it provides a head where every seat is identical in concentricity and depth. Next, valves are chrome plated and centerless ground to 8 thousandths oversize, and then each assembled head is vacuum tested to assure perfect sealing. All lifter bores are checked for burrs, and all oil lines are cleaned with solvent. The team is constantly cleaning and recleaning the engine surface. All moving parts are lubricated with Lubriplate, and this protective layer shields the new engine until its own lubricating system takes over. Now the recreated Gopher engine is ready to run smoothly.

6530 James Avenue North, Minneapolis, MN 55430
Phone: 763-746-3440 Fax: 763-746-3449 Toll Free: 800-328-3994

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