What makes engines fail and what do we need to think about when we build?
What makes engines fail? There are as many reasons as there are parts in an engine. What matters more is technique - how an engine is machined, prepped, and assembled. You can have all the best parts in the world. However, if you don't properly prepare these parts to work smoothly in concert, your engine is doomed. Marvin McAfee of MCE Engines in Los Angeles stresses extremes of attention to detail even when you're building a stock engine.
To ensure great engine building success, every single part from engine block to rocker arm nut must be checked. Marvin's policy is "trust, but verify..." Through a terrific friendship with Marvin, I've learned to leave no stone unturned. Close inspection begins at teardown. Each and every part must be inspected and measured. Wear patterns are everything to the integrity of a part. Do you know how to "read" parts? There are no unimportant parts, by the way. As you knock pistons and rods apart, measure rods for trueness (they're not always perfectly straight). Measure piston wear top to bottom. Measure bore wear. Crank and cam journals should be measured. Oil passages should all be checked. Block core shift can adversely affect oil galley positioning. Poor oil galley indexing can lead to oil starvation. Piston crown color and condition tells us how the engine was tuned and treated. The same came be said for valve and seat condition. Don't forget to check piston rings for breaks, cracks, and irregular wear patterns. Does it look like the engine ever overheated?
What you find during teardown is everything to why the engine failed or didn't live up to expectations.
When it's time to do machine work and assemble the new engine, all new parts must be massaged and blueprinted. Measure new parts. Remove stress risers that can cause abnormal wear and failure. Inspect for damage. Disassemble and measure new oil pumps. Never blindly install them without first inspecting. Ditto for any new parts right out of the box. Always degree the camshaft and check for true top-dead-center on all bores.
When you have covered all the bases, you can relax knowing you've done everything humanly possible to ensure engine building success.
If you would like to chat with Marvin McAfee or consult with him about building your engine, call 323-731-0462 or email at mceengines@aol.com.