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Do i lose Horse Power after time

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i thought after time every motor lost horsepower.

in high mileage engines piston rings lose their ability to seal compression causing a significant power loss. typically in older engines, without frequent oil changes using good quality oil this process is accelerated. but you should not have any issues with that. there are many other factors but this is the most common culprit of power loss over time.

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Assuming proper oil maintenance, piston rings last WELL over 150K-miles, and I've heard of cases (Caddilac 500) of rings going over 200K because if the metalurgy of the cylinder.


As most engines age the first major thing to go is valve seats, guides, and seals - the result is (1) a gunky oil/carbon buildup on the backsides of the valves which interferes with airflow and (2) worn valve seats leak compression and also interfere with airflow. All engine heads need rebuilding well before the bottom end, on canted valve motors (BBC) this is as early as 75K-miles, on our engines I am guessing somewhere in the 100+K range.


Another major source of power loss in engines is worn cam/lifters/timing chain. In distributor-fired engines a slack timing chain will also cause errant spark timing.


The other major HP killer is basic fuel and spark management - worn distributor (in older motors), carb is dirty or out of adjustment (older motors), and fouled/worn fuel injectors (modern PCM controlled motors).


Mr. P. :)

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