By Jim Kerr
We just smoked an engine – and I mean smoked! Sparks flew. The ground shook. Flames erupted and smoke billowed out from beneath the fenders. It was all in a good cause, however. Every year, students at our school pick one of the older salvage vehicles we use for training to raise money for cancer research. Hundreds gathered around (but not too close) to the vehicle to see who had guessed how long the engine would run at full throttle without any oil in the crankcase. Guesses ran from a few seconds to over 8 minutes.
In preparation for the event, the students warmed up the V8 engine completely, ensured it was operating correctly and then drained the engine oil and engine coolant. This was a wrecked vehicle but the engine had low kilometres on it and was in good shape – for a short while. As zero hour approached, the fire brigade stood guard armed with large chemical fire extinguishers (you can’t be too safe) and the school nurse was in attendance. After signing their names to the engine covers, the students closed the hood and started the clock and the engine. A brick was placed on the gas pedal and everybody watched with anticipation.
At first everything appeared to be normal. For over two minutes, the engine ran along at high rpm without any obvious damage. I thought it would have failed by now. Then suddenly it began to slow down. This was a sign of bearings seizing on crankshafts and pistons sticking in the cylinders. The engine ran slower and slower and the crowd started to think this was a dud. Then BANG!
The loud noise was followed quickly by a couple more as connecting rods broke and punched holes in the side of the engine block. It was a good thing we drained the coolant too or there would have been a large puddle to clean up. The engine revved back up again as the drag from the seized connecting rods was relieved and it continued to operate remarkably smoothly on only a few cylinders.
Steam from coolant and some smoke from hot oily parts started to seep from the fender gaps but the engine continued to run, and run, and run, and run. The five-minute mark passed. Finally, the engine started to make more clanking noises and the rpm started to surge. At the 5 minute, 41 second mark, it gave its last gasp as it dramatically shuddered to a stop and flames erupted in the engine compartment. Smoke billowed and the fire brigade was called into service, spraying the extinguishers into the grille opening and up from the bottom to quell the flames (never open the hood with an engine fire). It was over, almost.
After the official time was announced, students took the engine apart to diagnose what had failed. It was obvious that connecting rod bearings had seized on the crankshaft because of a lack of lubrication and that is what broke the connecting rods, but they also discovered that some parts such as the valves, lifters and camshaft had survived without any obvious damage. Even the pistons were in pretty good shape except where they had been struck by flailing connecting rods.
Besides raising money for charity, the destruction of this engine showed how important lubrication is to the life of an engine. Run low on engine oil and the first items to fail are usually the connecting rod bearings. Sometimes this can destroy the entire engine. Even a good engine won’t last long without proper lubrication.
Car Care Canada ran free car inspections across Canada last May to highlight the importance of car maintenance to safety, protecting the environment and protecting your investment in your vehicle. Of the vehicles inspected, there was a 78% failure rate. Even though newer vehicles require much less maintenance than vehicles of a few decades ago, they still do need to be maintained. Putting off vehicle
maintenance may appear to save money, but it costs in the long run. By the way, when was the last time you had your engine oil checked? We have a slightly used one if yours gets “smoked”.