Every Mechanic knows this feeling…

How do two tiny pieces of metal hold back this massive spring?! ⚙️💥 Inside your car's engine, stiff steel coil springs rapidly open and close the valves thousands of times a minute! This specific valve spring is significantly longer than most, meaning it holds a terrifying amount of tension! To lock this massive spring safely down, mechanics face a high-stakes puzzle! Using a heavy compressor tool, they violently crush the long steel coil. While it is under massive pressure, they carefully use their bare fingers to drop two microscopic metal wedges (called keepers) directly into the grooves on the valve stem! If the tool slips, this extra-long spring will launch across the garage like a missile! But when they carefully release the tension, the massive pressure pushes up against the tiny wedges, locking the explosive assembly safely together!