Camshaft install tips and tricks
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===Engine RPM for break in=== | ===Engine RPM for break in=== | ||
| − | '''10. Failure to run the motor at high rpms (2500 or higher, alternating 500/1000 rpm's up and/or down to allow the crank to throw oil in different places at different revs) for | + | '''10. Failure to run the motor at high rpms (2500 or higher, alternating 500/1000 rpm's up and/or down to allow the crank to throw oil in different places at different revs) for a minimum of 20 minutes. |
| − | No idling! The motor should not be run at less than 2500 rpm's for a minimum of | + | No idling! The motor should not be run at less than 2500 rpm's for a minimum of 20 minutes. If a problem develops, shut the motor down and fix it, then resume break-in. The main source of camshaft lubrication is oil thrown off of the crankshaft at speed, drain back from the oil rings and oil vapors circulating in the crankcase. At idle, the crank isn't spinning fast enough to provide sufficient oil splash to the camshaft/lifters for proper break-in protection. |
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'''12. Failure to initially adjust the valves properly.''' | '''12. Failure to initially adjust the valves properly.''' | ||
| − | Using the "spin the pushrod until it feels tight" method | + | Using the "spin the pushrod until it feels tight" method may result in valves too tight. Holding the rocker arm tip down against the valve stem tip with one hand, jiggle the pushrod up and down with your thumb/forefinger of your other hand until all play is removed, then turn the rocker nut the number of times specified by the lifter manufacturer to set the preload. (Another good reason to buy lifters from someone you can talk with about them on the phone instead of buying them in a white cardboard box with no name on it). Builders who have done hundreds of engine builds may have the "feel" to do the "twist" method, but those who are doing their first few builds lack the experience to do this and will have better results with the "jiggle the pushrod up and down" method. |
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'''14. Failure to have everything ready for the motor to fire on the first few turns.''' | '''14. Failure to have everything ready for the motor to fire on the first few turns.''' | ||
| − | Fully charged battery, good starter, known-good carburetor with full fuel bowl, source of fuel to the carburetor to allow minimum | + | Fully charged battery, good starter, known-good carburetor with full fuel bowl, source of fuel to the carburetor to allow minimum 20 minutes of uninterrupted running. Ignition timing set. Warning: no grinding on the starter! |
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