4 bangers part II

[PandaBear]

There are many non-boosted 4 bangers with small displacement (1.6/1.8) that produce decent HP and last very long. The key is to do it right, but it ain't cheap.

Example:

Honda Civic Si/Delsol with 1.6L VTEC, 140HP and has a gear ratio that is 4000rpm at 70mph. It is designed with long rod, short crank to keep the power band high (no torque below 3500rpm) and very short gear ratio. Can easily last 300k without problem. Integra with 1.8L VTEC that goes from 170 (GSR) to 195(Type R) HP is another one, easily last 300k without problem and is the most reliable Honda out there (more reliable than Accord and Civic).

To make it durable you have to get good design, like oil jet to cool the piston bottom, moly coat piston skirt, variable valve timing, oil cooler, high silicon alumnium alloy piston, AND HIGH PRECISION PARTS. You can't expect to get an engine design for low rpm to constantly run at high rpm and expect reliability, and you can't expect an engine design for high rpm to constantly run at low rpm and expect torque.

I am sure they can do a 4 banger right if they want, just that most consumers have a "got to get a V6" mind set. The big 3 sell displacement for cheap, and Americans love displacement, so thats what they are doing.

 

[VNT]

I think most Americans like tourque.

My friend just bought a new civic. Has 1.8 iVTEC 140Hp at 6300RPM but a lame 128 ft-lbs of tourqe at 4200RPM. It couldnt get out of its own way and I know he will not be happy with it other than the decent gas mileage, says he avg about 34 MPG HWY.

HP doent mean anything if its way up in RPM band were most people dont drive. My low tech 2.5 turbo has 285 ft-lns of tourque at 3000 RPM and over 250ft-lbs from 2600 to 4700, this at the wheels. not bad for a SOHC 20 yr old design.
Has 205 K miles on it and gets 30 mpg highway.

 

[brianl703]

Ford's 2.5L Duratec V6 redlines at 6750RPM (as far as how the torque is there, for fastest acceleration shifting at redline is best), and produces 75% of it's peak torque at 1500RPM (so one can, for example, accelerate from 15MPH in 4th gear).

It's interesting to note that they no longer use this engine except in a couple of applications, having replaced it with a 2.3L I4. I heard that this is because the patent on using balance shafts in an I4 engine expired (and I suspect the I4 is cheaper to make).

 

[carock]

"All things being equal" is the catch all phrase here. You can squirt oil to the underside of a piston on a normally aspirated car as well as a turbocharged car to prolong the life of the piston. Several manufacturers do this, VW, Audi, Porsche, Saab, BMW, and others. The fact is the hotter the piston runs, the shorter its life span.It seems to me that a 4 cylinder engine would run higher piston temperatures than an eight cylinder engine, and turbo four cylinder engines do not have a reputation for extremely long life. Chrysler, Volvo,VW, and Saab turbocharged engines definitely did not have longer life spans than the normally aspirated versions of their four cylinder motors. I should know, I worked on them for years. Of course there are lots of exceptions based on manufacturing variables and owner care issues. I still think that the load per inch of piston area is a determining factor in engine lifespans. The piston can only take so much heat and still maintain the integrity of the ring land.

With respect to a four cylinder engine operating at 78% load at 4500 rpm, and an eight cylinder engine operating at 95% load and 2600 rpm, look at the load per square inch of piston area, the four cylinder piston is operating at a higher temperature.It is also operating at a higher RPM, which will wear the valvetrain faster."All things being equal".

With respect to exhaust gas temperatures, the actual LOAD on the engine determines the HEAT input to the motor. It is entirely possible to run an engine at high exhaust gas temps, and only a partial load. Temperatures do not necessarily destroy engine parts, it is the combination of heat AND temperature. This subtle difference in terminology takes time to fully understand. Gas temperatures in the cylinders build into high metal temperatures when there is more heat being produced than the cooling system can take away.The only engine part that really suffers from high exhaust temperatures in low-medium load conditions is the exhaust valve.

 

[OriginHacker21]

Thanks for that explanation carock (rpms - valvetrain). Never understood it that way before. Always think of load as the ultimate wear and tear on engine.

 

[bob_ninja]

carock,
So that is why motorcycle engines need a rebuild sooner because of 2x and 3x RPMs. I've heard of some riders cruising at 10K RPM (then again their redline is at 16K or 17K RPM).

These days there are car models showing up that reduce engine size to 4 and 3 cylinders (such as Hornet or Smart, Prius, etc) but add turbo to get the sufficient power output. Often these are diesel engines. I wonder how their longevity will compare with an average V6 car.

On another note, the "power assist" should then prolong engine life as it removes some of the burden on engine from high load (acceleration) situations. If done right the conventional engine could operate at its optimum RPM while the electric motor kicks in to handle high load demands. Maybe this could replace the need for turbo, so long as they can manage the pricing issues. High load and temps would not be an issues and you could use a 0W20 oil without fear.

 

[eljefino]

there's a guy named Luke on saturnfans with 430k miles on a 95 SL2 DOHC 4 cyl 1.9l.

Yeah it burns oil, but he gets 40mpg. The secret: he self-admittedly drives like an old geezer.

 

[John K]

Don't forget the Volvo P1800 that went past a million miles.... Don't remember the horsepower though.

 

[ALS]

quote:

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Originally posted by John K:
Don't forget the Volvo P1800 that went past a million miles.... Don't remember the horsepower though.

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Mid October 2005 Irv Gordon passed 2.4 million miles in his 1966 1800. BTW Volvo pays for every little thing on that car other than Gas and insurance from what I have heard.
It has an 1.8L 115 HP In-line 4 in it.

 

[ALS]

quote:

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Originally posted by carock:
It has always been my theory that engines can only tolerate so much heat per square inch of piston area. So the greater load the engine operates at, the sooner it will fail. I learned this hot rodding turbo charged engines, where the pistons get hot and the ring lands fail.This is a common failure mechanism in well maintained engines and there is no way to fight it. Over time the ring lands get hammered to a larger gap and the piston ring starts to fail. The hotter the piston runs the sooner this happens. So "all things being equal" the four cyclinder engines wear out sooner because the pistons run hotter.

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There are thousands of Volvo 4 cylinder Turbo engines out there still running strong at 200K miles plus. Volvo addressed the problem you described back in 1994 by adding oil squirters to the engine blocks. These squirters bath the underside of the piston with oil. Thus oil cooled the pistons. This solved a lot of problems associated with owners turning up the wick as they say.

 

[brianl703]

Wiring and connectors have gotten much better. 20 years ago, most cars had wiring with connectors that aren't sealed. Water could get inside and corrode them.

Then they also figured out that using better insulation would prevent it from breaking down and cracking due to the heat.

 

[toocrazy2yoo]

My 92 Elantra had 1/4 million miles on it, and the electricals were fine and dandy, thankfully. The engine was fine, with 165K on it (first owner blew the engine via rotton timing belt). Problem was, the suspension bushings, struts and springs were shot. No rust in the body. The thing that pushed me over the cliff with my 92 was a whining noise suddenly coming from the timing-belt side of the engine where the power steering, alternator and AC belts come together. It sounded very expensive, the car was nearly in need of a clutch, and a timing belt in 8K miles. When you're looking at thousands to service the peripherals, what you have to keep in mind is that in the end you still have a car with 250K miles that's 15 years old. Can they design better peripherals to match the longevity of the power train? Perhaps, but who besides a knucklehead like me keeps a car this long, anyway? Especially a Hyundai, essentially a throwaway car to nearly all who buy them, excepting, of course, knuckleheads like me!

All in all, a great car, but when all the other systems go old at once, you really can't justify pouring in the cash, regardless of how well the engine/tranny are running. Kinda renders all the lubrication issues moot. It carried me a loooooong way over the years but it became time to put it to bed.

Rest In Pieces!

 

[carock]

You can't beat the old Volvo four cylinder engines for durability. The metallurgy and materials used were extremely good compared to other cars. Volvos in that era were also designed to start reliably at 50 degrees Farenheight below zero. To achieve this they designed larger bearings and other wear surfaces. This gave the added benefit of long life. If you wanted a durable car in the 60's and early 70's, Volvo was a great choice.

These days,I expect the engine to outlast the rest of the car. Obviously, that does not always happen. I normally expect a modern car to need replacing due to body rust or electrical problems. When the wiring harness deteriorates a car develops a lot of intermittant electrical problems and pretty much has to be scrapped.It is usually very impractical to replace the wiring harness and associated computers/sensors as they age.Electronics is an area where manufacturers can precisely calculate life spans and "planned obsolesence".

 

[PandaBear]

quote:

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Rest In Pieces!

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Or get a second life as a whole in the 3rd world. They have lower labor cost that makes rebuilding an old car like this very practical. A friend of mine from Mexico told me that most of their cars on the road come from used cars in the US. Another friend told me the mechanics over there can put any engine in any car you wanted, like a Chevy V8 in a Lexus SC400.

 

[pezzy669]

I fully believe that 4 cylinders last just as long as 5/6/8 cylinders despite being worked more per say.

My sister had a '93 Civic EX (1.6L VTEC 127HP) that had 27X,000 miles on it when after a faulty oil change (oil filter gasket left on) it puked its oil and seized. It burned no oil and still got over 30MPG.

I am happy with my 2.5L 5 banger. 25-27 MPG city, power of a small 6, enough torque to accelerate from 1200 RPM and 0-60 of ~8 seconds. Not sure how durable as it is a newly designed engine, but VW typically overbuilds their engines anyways.

 

[robbobster]

I think relative stress levels of the engine play a large role. A Honda coupe isn't a heavy load, and the engine is sized appropriately.

Same with, say, a Crown Victoria V8 sedan.

I don't think the Honda engine would fare well in the CV, just as I don't think the CV engine would fare well in a large delivery truck.

 

[buster]

I'm having a hard time dealing with the power loss due to the AC running. I don't know if I can deal with it for 4 more years.

 

[rpn453]

quote:

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Originally posted by buster:
I'm having a hard time dealing with the power loss due to the AC running.

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Sounds like you need a bigger 4-banger!

 

[brianl703]

I test-drove a 4-banger that had no power loss whatsoever when the AC is turned on.

'course, it is turbocharged...maybe that has something to do with it???

 

[technician]

quote:

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Originally posted by bob_ninja:

170 hp from 1.6L

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Different engine design but my 1.3L rotary is outputting 470HP (twin-turbo). There are also a lot of *small* litre engines running in Forumula 1 that would destroy my rotary.

As for 4-cylinders lasting long many people are getting in excess of 300,000 miles off the in-line four's found in Jeep Wranglers. In-line engines will last longer and give you a bit more torque, just too bad we don't see too many of them in newer vehicles (though I believe the Jetta is using in-line 4's).