Horsepower Loss Overtime?

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Do engines lose power overtime as the miles accumulate? I would imagine that power loss and maintenance would have a positive correlation. Is there a rule of thumb for engines losing power at say 50K, 100K or 150K miles?
 
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Depends on a lot of things but I would assume the answer is yes. Engines wear over time. Today's engines are lasting longer than ever.
 
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I dont think you'ld see a loss at 50K due to wear. Carbon buildup on piston tops and valves causing early ping or detonation and poor preserved atomisation but not wear with strong oil. Then you have cat plugging.
 
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I imagine engines gain horsepower intitially due to breaking in. I also believe engine builders will use "looser" clearances if building for hp and not longevity. I think most passenger cars lose most of their hp due to detiorating ignition and partailly clogged cats, or injectors falling out of specs, more than actual engine wear.
 
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 Originally Posted By: CharlieJ
Do engines lose power overtime as the miles accumulate? I would imagine that power loss and maintenance would have a positive correlation. Is there a rule of thumb for engines losing power at say 50K, 100K or 150K miles?
My car's engine was still loosening up noticeably at 50k miles. At over 180 k miles the engine revs more freely and offers better acceleration than ever. I can't comment on achievable top speed and a possible change over time, since the top speed is governed. Unless compression suffers due to excessive wear, and presuming all other relevant components (inteake, exhaust, ignition, etc) are in fine shape, I don't think an engine will lose power with age.
 

CharlieJ

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Ok, I forgot about the ignition and fuel systems. I was thinking from the oil's point of view such as compression loss from wear of the piston rings and cylinder walls.
 
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That's why we used to do compression checks at every major service. Sadly, routine compression checks are not part of standard maintenance any longer.
 

CharlieJ

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 Originally Posted By: moribundman
My car's engine was still loosening up noticeably at 50k miles. At over 180 k miles the engine revs more freely and offers better acceleration than ever. I can't comment on achievable top speed and a possible change over time, since the top speed is governed. Unless compression suffers due to excessive wear, and presuming all other relevant components (inteake, exhaust, ignition, etc) are in fine shape, I don't think an engine will lose power with age.
That is good to know. Sounds like with proper maintenance power loss should not be much of an issue.
 
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 Originally Posted By: moribundman
 Originally Posted By: CharlieJ
Do engines lose power overtime as the miles accumulate? I would imagine that power loss and maintenance would have a positive correlation. Is there a rule of thumb for engines losing power at say 50K, 100K or 150K miles?
My car's engine was still loosening up noticeably at 50k miles. At over 180 k miles the engine revs more freely and offers better acceleration than ever. I can't comment on achievable top speed and a possible change over time, since the top speed is governed. Unless compression suffers due to excessive wear, and presuming all other relevant components (inteake, exhaust, ignition, etc) are in fine shape, I don't think an engine will lose power with age.
Exactly! Not until the engine is on the steep downward wear slope will you see a decrease. I think it makes the same or more power until it's on that downward slope which probably won't occur before 300,000 for modern cars. 100,000 miles is nothing as far as power loss from engine wear.
 
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 Originally Posted By: BuickGN
 Originally Posted By: moribundman
 Originally Posted By: CharlieJ
Do engines lose power overtime as the miles accumulate? I would imagine that power loss and maintenance would have a positive correlation. Is there a rule of thumb for engines losing power at say 50K, 100K or 150K miles?
My car's engine was still loosening up noticeably at 50k miles. At over 180 k miles the engine revs more freely and offers better acceleration than ever. I can't comment on achievable top speed and a possible change over time, since the top speed is governed. Unless compression suffers due to excessive wear, and presuming all other relevant components (inteake, exhaust, ignition, etc) are in fine shape, I don't think an engine will lose power with age.
Exactly! Not until the engine is on the steep downward wear slope will you see a decrease. I think it makes the same or more power until it's on that downward slope which probably won't occur before 300,000 for modern cars. 100,000 miles is nothing as far as power loss from engine wear.
+1
 
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 Originally Posted By: Rabbler
Sounds contrary to what the oil additive companies would have us think...
You haven't watch the Q Horsepower commercial. Man, it's like a herd of wild mustangs just jumping right out from under the hood.
 
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 Originally Posted By: oilyriser
When the cylinder wears, it gets bigger!
And the cylinder cross section becomes oval over time. However, engines with over 100k miles frequently still show the factory cross hatch pattern finish on the cylinder wall, so wear is really minute. Rings will likely wear out faster than cylinder walls.
 
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All the cars and motorcycles I have every owned seemed to have the most power at the time I parted with them. Of course they were all maintained to perfection. The car I owned with the most mileage was a 1985ish Volvo 760 turbo. I ran Pennzoil 5W-30 for 110k miles. The engine was spotless and the car never needed a part other than routine maintenance. No oil was ever used. And I drove it hard. I know that is hard to believe. I traded it in for the new 600SEL MB that came out in 1992. aehaas
 
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