What happens if I shift to first gear on manual transmission while driving at 130 kph? – Patrick
Engaging first gear from that high of a speed would be quite the accomplishment considering the physical layout of the shifter pattern and the movements required to make that happen.
If you did manage such a sophisticated miss-shift, then you would also be fighting the transmission's synchronizer mechanisms, which are attempting to match the speeds of the internal input and output shafts. Hence, completing such a faulty shift would require a generous amount of force from the driver.
But there are rare occasions when an enthusiastic gearhead completes this action.
Within the engine at that point, an over-rev condition will occur and internal-engine components will momentarily spin far faster than what they were originally designed to do. The valve spring keeps the engine's valves seated, opening and closing following the camshaft lobe. When the engine's speed dramatically increases, the sudden elevated momentum will overwhelm the capabilities of the valve spring and the valve will float off the camshaft, leaving it suspended within the combustion chamber.
In many of today's vehicles, "interference engines" are designed so that the valve and the piston can never occupy the same same space at the same time. If this occurs, as in the case above, then internal-engine components will collide, leading to a variety of unwelcome repairs.
Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing "Lou's Garage" in the subject area.
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