Recommended Break-In Procedure for Rebuilt Engines

 

 

Protect the investment you have in your engine. Take the time to read and follow these recommendations.

 

• Before starting your rebuilt engine for the first time, be sure it is pressure lubricated. This means priming the oil pump by turning engine over with starter without spark plugs. NEVER add cold water to the cooling 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.
• To break-in a new camshaft run the engine at 1800-2400 RPM for three sets of 15 minutes, making sure to adjust the timing during the first run. Try to vary the idle a little throughout the break-in process to change oil spray pattern and pressure. After each run, let the engine cool down before starting the next set. After the first run remove the valve cover and check the valves, as they will likely need to be readjusted when the engine is warm. If a loud tapping is present during the break-in one of the valves may be too loose and will need to be tightened. Also re-torque the head bolts since most of them will change when heated up. Once the camshaft is properly broken in you are ready to start enjoying your engines new found power!
• 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 coolant may rise to operating temperature in a few minutes. Conduct a visual inspection for coolant or oil leaks around and under the engine. Adjust carburetor and ignition timing once engine is warmed to operation temperature. If the coolant should 'boil over' stop engine and allow to cool down for 30 minutes then start again, add water and proceed as above.
• Stop the engine and re-torque head and exhaust 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, in 'drive' range or select proper gears for standard transmission. At 30 miles per hour open throttle wide open and accelerate to 50 miles per hour then remove foot from accelerator letting engine slow vehicle down to 30 mph, then open throttle wide open and accelerate back up to 50 mph. Repeat this procedure at least 10 times.
• 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 500 miles. Note 30 weight for break-in.
• ENGINE OR VEHICLE SERVICE RECOMMENDATIONS FOR TRUCKS: Run with light loads from 500 miles and avoid 'lugging.' Acceleration and deceleration in proper gear during this break-in period is advisable. Then change the oil and filter.
• After 1,000 miles of service, re-torque cylinder heads and manifolds to proper specifications unless a TTY bolt is used. Re-adjust tappets. We suggest that this be done again at 5,000 miles. We know this means extra work but it assures long and satisfactory engine performance.
• The rings will seat 90% of the way in the first 20 minutes. Full break in can take up to 500 miles.
• And as stated above, re-torque your head bolts and adjust your valves after initial break in. I recommend an oil additive for initial break in that is high in zinc and phosphorous for break in if your engine is a flat tappet engine. (First initial run only)