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Destroyed big end bearings

Practical Engine Building

Discussion and questions related to the course Practical Engine Building


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I had a engine suffer a oil leak and spike boost from 10 psi to 18 psi the bearings got shot i have a feeling its to much timing for the 18psi boost and the engine was knocking and destroyed the bearings or maybe oil leak the dip stick was empty. Andre is to much timing and the engine stress as the plug is fired to early knock ? And also fuel burning to quick or outvof control also knock ? Both cases are called knock events? What do you think has been the cause looking at the bearings?

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While knock can indeed damage the bearings, I've yet to see an instance where the bearings showed sign of damage without some much more obvious signs of knock on the actual piston itself. It is interesting that one half of your shells looks worse than the other (typical where the bearing is being pounded by knock), but I don't know enough about what I'm looking at - Are these two shells from one rod? The fact you have no oil on the dip stick would make oil starvation my first guess.