Recommended Break-inProcedures for rebuilt engines.

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Recommended Break-In Procedure for Rebuilt Engines

Protect the investment you have in your engine. Take the time to read and follow these recommendations from
  • Before starting your rebuilt engine for the first time, be sure it is pressure lubricated. This means priming the oil pump with oil shaft rod or turn engine over with starter without spark plugs.
  • NEVER add cold water to the colling system while the engine is running. The engine should be allowed to run at normal operating temperature. If not, shut down and wait 30 minutes, then restart.
  • Start the engine and run at a fast idle, approximately 1500 RPM, and check oil pressure. Run the engine for 30 minutes even though the collant may rise to operating temperature in a few minutes. Adjust carburetor and ignition timing. If the coolant should 'boil over,' stop engine and allow to cool down for 30 minutes, then start again and add water, and then proceed as above.
  • Stop the engine and re-torque head and manifold to engine manufacturer's specifications in proper sequence. Readjust tappets if necessary. NOTE: look for any leaks, upper and lower.
  • Start engine again and make a test run on the road at 30 mph in 'drive' range or select proper gears for standard transmission. Periodically open throttle and accelerate to 50 mph and decelerate rapidly. Repeat this procedure at least 10 times. For a large truck or industrial engine, accelerate in intermediate gears as above. NOTE: Applying light loads to the engine for short periods of time causes increased ring pressure against the cylinder walls and helps to seat the rings. This is especially important because you are 'breaking-in- the engine with heavy duty oils. The rapid deceleration increases vacuum and gives extra lubrication to the pistons and ring assemblies, also helps lubricate the whole engine.
  • ENGINE OR VEHICLE SERVICE RECOMMENDATIONS FOR PASSENGER CARS: Drive normally but not at continuous speeds for the first 500 to 1000 miles. Occasional fluctuation of speed followed by deceleration during this first period of break-in is beneficial. Then make sure to change oil and filter on or before the first 1000 miles. Note 30 weight for break-in.
  • ENGINE OR VEHICLE SERVICE RECOMMENDATIONS FOR TRUCKS: Run with light loads from 500 miles and avoid 'lugging.' Occasional acceleration and deceleration in proper gear during this break-in period is advisable. Then change the oil and filter, 30 weight.
  • ENGINE OR VEHICLE SERVICE RECOMMENDATIONS FOR INDUSTRIAL ENGINES: Follow above instructions and operate under partial loads for several hours. Change oil and filter after approximately 10 to 20 hours of operation.
  • After 1,000 miles of service, re-torque cylinder heads and manifolds to proper specifications. Re-adjust tappets. We suggest that this be done again at 6,000 miles. We know this means extra work, but it assures long and satisfactory engine performance.
21632 N 7th. Ave. Phoenix Az. 85027

SW corner of 7th Ave & Deer Valley Rd, right across from Deer Valley Airport entrance.
telephone: 602 866-8044       email:

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Disclaimer: Please note that any information on this website, including pricing, is deemed accurate but is not guaranteed. Any pricing information is presented as a guideline only; you must call or email us for a customized estimate. Thank you.

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