Hp deterioration ?

[B1SiR6A]

Should a stock used car motor in "ok" to "good" condition still have stock hp or is there a deterioration of hp over the years

[BullShifter]

slight deterioration - it all depends on the internal engine condition

[Prelussion]

Some older engines like in CRXs will actually have MORE hp than stock due to increased compression from carbon buildup. I wouldn't hope for this though if buying a used engine.

[B1SiR6A]

im not buying the engine...im buying a JDM SiR (B16A) and I was just wondering if the horsepower would be the same as stock...thanks for answerin my ques...can you go more in depth with this increased compression thing in the older CRX engines....?

[rubix777]

I supposed lifter noise would mean decreased hp?

[Prelussion]

well not just CRX motors or anything, i was just using that as an example cause they're old. But when the carbon deposits build up on these older, high milage cars, it builds up so much that the carbon buildup takes up space on the piston and walls, thus increasing horsepower.
I've heard of people actually losing HP when they run engine cleaning fluids and what not.

[thepolishmafia1337]

Originally Posted by Prelussion

well not just CRX motors or anything, i was just using that as an example cause they're old. But when the carbon deposits build up on these older, high milage cars, it builds up so much that the carbon buildup takes up space on the piston and walls, thus increasing horsepower.
I've heard of people actually losing HP when they run engine cleaning fluids and what not.

would it be safe to assume that if there were enough carbon built up in the combustion chamber to increase compression ratio, that the intake runners and exaust runners would also have the same amount of carbon build up if not more than the combustion chamber?? if this were the case then there would be much more power lost through restriction and unatomized air. also whats increased in compression in carbon would probably be lost in wear and tear on the piston rings and the valve seats.
to answer the thread no a stock motor will only decrease in hp there are small exceptions, after the break in period motors have been known to make minor hp gains. when i say minor i mean minor. less than 2hp. or if along the waysomeone changed the head gasket or rebuilt the motor but the hp gains are not even worth measuring. who cares if you have 123 hp instead of 120 hp your still slow.

[vesper]

Originally Posted by thepolishmafia1337

would it be safe to assume that if there were enough carbon built up in the combustion chamber to increase compression ratio, that the intake runners and exaust runners would also have the same amount of carbon build up if not more than the combustion chamber?? if this were the case then there would be much more power lost through restriction and unatomized air. also whats increased in compression in carbon would probably be lost in wear and tear on the piston rings and the valve seats.
to answer the thread no a stock motor will only decrease in hp there are small exceptions, after the break in period motors have been known to make minor hp gains. when i say minor i mean minor. less than 2hp. or if along the waysomeone changed the head gasket or rebuilt the motor but the hp gains are not even worth measuring. who cares if you have 123 hp instead of 120 hp your still slow.

agreed, more horse power due to carbon build up is not a car for a daily driver. in your case the b16, i wouldnt worry about that. replace parts as
needed. as you know seals and other things among that will go through the years.

whats up with the 123 hp instead of 120 hp your still slow.
are you getting cocky?

[B1SiR6A]

Ok great i dont think any of the previous owners of this car have done any work of that kind of extent so I should still have my stock 170 horses...Im still not sure if its even an SiR...it has the badge and the owner says its DoHc VtEc but I think he was only sure about the VtEc part because he looked kinda confused when I said DoHc...but im going to see it monday i'll let you guys (whoever cares) know what the outcome is...

Thanks again for answering my question prelussion and polishedmafia

[thepolishmafia1337]

vesper:it sounded to me like the guy was playing off carbon build up like its a good thing that makes hp because in increases your compression ratio. and the numbers 123 and 120 were only and example on how 3 horsepower means nothing when you only have 123 hp. it coulda been any number. ex: if you had two almost exactly the same honda civic si only difference is miles. guy "A" claims to have more horsepower because he has carbon build up in the combustion chambers which as we all know increases compresion(---haha) guy "B" has les miles he changes his oil and pcv valve regularly. if you ride in there cars will you be able to tell the difference between the two or better yet if they race who would win??? i was just putting somethin out there.

[boosted331]

Originally Posted by Prelussion

Some older engines like in CRXs will actually have MORE hp than stock due to increased compression from carbon buildup. I wouldn't hope for this though if buying a used engine.

I doubt it, the wear on the rings would case enough compression loss to more than negate the slight increase in compression carbon buildup would give you.

[bbyzfr6]

Hey guess what...I'm sure the compression can vary due to assembly line process and the mfg. deck height and head cc. I bet you can take a sample of engines being brand new and get different hp ratings.

Thats why a good machine shop can do a basic rebuild and squeeze up to 15 hp out of a crate motor. Yeah plenty of people might think I am crazy, but that's how industry works. Things called acceptable tolerances.

I'd agree with boosted331 about the rings! I'd also now like to follow up with yes the power would be down due to wear in several areas within the combustion chamber. cylinder valves ect. Probably not a lot, but it's hard to quantify.

[Spectre927]

Originally Posted by bbyzfr6

Hey guess what...I'm sure the compression can vary due to assembly line process and the mfg. deck height and head cc. I bet you can take a sample of engines being brand new and get different hp ratings.

Thats why a good machine shop can do a basic rebuild and squeeze up to 15 hp out of a crate motor. Yeah plenty of people might think I am crazy, but that's how industry works. Things called acceptable tolerances.

I'd agree with boosted331 about the rings! I'd also now like to follow up with yes the power would be down due to wear in several areas within the combustion chamber. cylinder valves ect. Probably not a lot, but it's hard to quantify.

I know. You gotta watch those acceptable tolerances... they're every where, like how many bug parts can be in ketchup... they even have them for condom breakage...

[bbyzfr6]

Yeah I hear ya...that's why the condom box still has a CYA statement on it and it isn't 100% all the time.

After being around a machine shop and seeing the .010 short cuts here and there it all adds up. Never know who is operating the machine that day or what time they take their nap. Or maybe tool wear vs. offsets hell I dunno maybe I'm clueless about this kind of thing...

Oh for the carbon build up guy...would the carbon be on the valves too causeing cylinder pressure to bleed off?

[pheurton-skeurto]

chloraphil...more like BORA-PHILL!!!