Does anyone offroad here???

[Captain Obvious]

I have some bumpers to build and a gas issue to resolve, then am hoping to start hitting some of the milder trails.

[Aaron]

I don't know why you guys don't offroad on nicer roads like me. But I guess I also have a much better Chrysler motor too!

[grim]

Nothing wrong with the inline 6 those things were amazing but the oil pan was placed in a shitty position.

[birchyboy]

Nothing wrong with the inline 6 those things were amazing but the oil pan was placed in a shitty position.

Under the engine? Where else could it go

[Keyser Soze]

I go up a few times a year.

Poseur!

[Penadam]

Nothing wrong with the inline 6 those things were amazing but the oil pan was placed in a shitty position.

Things wrong with the inline six:

Awful specific HP, both on a weight and displacement basis
Awful fuel economy
Awful overall power
Rear and front seals guaranteed to leak
Took forever to warm up in the winter

Things good about the inline six:
Cheap parts
7 main bearing made it impossible to destroy

[grim]

Things wrong with the inline six:

Awful specific HP, both on a weight and displacement basis
Awful fuel economy
Awful overall power
Rear and front seals guaranteed to leak
Took forever to warm up in the winter

Things good about the inline six:
Cheap parts
7 main bearing made it impossible to destroy

Awful fuel economy, Its a jeep no shit!
Awful overall power, Mine had plenty of power, you plan on hauling semi trailers?
Rear and front seals guaranteed to leak, Mine didn't because i pumped grease in them every 3 months.
Took forever to warm up in the winter, Block heater

Things good about the inline six:
Cheap parts

[Penadam]

Awful fuel economy, Its a jeep no shit!
Awful overall power, Mine had plenty of power, you plan on hauling semi trailers?
Rear and front seals guaranteed to leak, Mine didn't because i pumped grease in them every 3 months.
Took forever to warm up in the winter, Block heater

Things good about the inline six:
Cheap parts

I-6 from 2006
190 hp, 225 ft-lbs
13 city, 16 highway with the automatic, 17 highway with the manual

V-6 from 2012
285 hp, 260 ft-lbs
17 city, 21 highway with both transmissions for the 2 door

How does one grease a front and rear main seal?

[grim]

How does one grease a front and rear main seal?

Put a thick high temp grease on the outside edge were it says "soap on outside of seal" The grease keeps the dirt, dust, debris, and water out of the seal so it doesn't wear down so fast.

[Aaron]

Things wrong with the inline six:

Awful specific HP, both on a weight and displacement basis
Awful fuel economy
Awful overall power
Rear and front seals guaranteed to leak
Took forever to warm up in the winter

Things good about the inline six:
Cheap parts
7 main bearing made it impossible to destroy

The 4.0 did have awful specific output, however this is not always a bad thing. There are thousands of engines which are specifically designed as to not have high specific output. High specific output goes hand in hand with poor durability and reliability, because the engine is operating at the limit, all the time.

Our bikes are a good example, they have some of the highest specific output engines made right now. How many miles does a typical sportbike engine last? 40, maybe 50,000? And I've seen plenty blown up by 20k. Fact is the high compression, high RPM, high piston speeds, and high output all decrease reliability and durability.

The 4.0 was indestructible, it'd never die. Part of this is like you said the main bearings, but it was also all-iron, an inline design, and had low specific output and low RPMs, all contributing to its reliability and durability. This hurts fuel economy and warmup times, but that was a trade Chrysler was willing to make.

Now I'm sure the Pentastar will have good reliability too, but technology today has come a long way since when the 4.0 was designed, and now they are able to raise specific output, without unreliability coming with it.

Good specific output is not a good thing for any vehicle, unless that vehicle is competing in a displacement limiting class. Let's look at the GM LSX, the best automobile engine in a production car right now. Specific output for any of the LSX engines is quite low, the LS1 is at like 61hp/l, and the highest LS7 is at 72. All really mild in a day where 100hp/l is almost common.

But the LSX dominates in performance. It yields good gas mileage (A 350hp SS Camaro will do 31mpg hwy), the motor is extremely light, it's very small in physical size, the engine runs smooth, power and torque are some of the highest offered in a car today, and yet reliability is still excellent. The motor is fantastic, whether it's in a full size 2500 truck, a Z06 Corvette, an Impala, a Hummer, or a Nissan Skyline. Fact is, specific output is a moronic figure unless you are in a displacement limiting class.

[Filo]

Slightly off topic, but still apropos...

My 13 year old son has decided he wants a Jeep (Wrangler/CJ style) as his first car. The reason this comes up now is that he is going to refurb one that has been neglected. I have done plenty of motor work, but I know nothing about Jeeps. Any inputs on years/engines to avoid/look for? Stuff like the pros and cons you guys have for the inline 6. Also, if anyone has a cheap one needing some work they want to unload, let me know. I am not a big fan of body work from a crash though, so lets avoid that if we can...

[Penadam]

Put a thick high temp grease on the outside edge were it says "soap on outside of seal" The grease keeps the dirt, dust, debris, and water out of the seal so it doesn't wear down so fast.

You would drop you oil pan and remove the bearing caps every 3 months? Sounds awful.

The 4.0 did have awful specific output, however this is not always a bad thing. There are thousands of engines which are specifically designed as to not have high specific output. High specific output goes hand in hand with poor durability and reliability, because the engine is operating at the limit, all the time.

Good specific output is not a good thing for any vehicle, unless that vehicle is competing in a displacement limiting class. Let's look at the GM LSX, the best automobile engine in a production car right now. Specific output for any of the LSX engines is quite low, the LS1 is at like 61hp/l, and the highest LS7 is at 72. All really mild in a day where 100hp/l is almost common.

But the LSX dominates in performance. It yields good gas mileage (A 350hp SS Camaro will do 31mpg hwy), the motor is extremely light, it's very small in physical size, the engine runs smooth, power and torque are some of the highest offered in a car today, and yet reliability is still excellent. The motor is fantastic, whether it's in a full size 2500 truck, a Z06 Corvette, an Impala, a Hummer, or a Nissan Skyline. Fact is, specific output is a moronic figure unless you are in a displacement limiting class.

The specific output of the I-6 was 48 hp/L and weighed 515 pounds.
The specific output of the V-6 is 80.5hp/L and weight is 383 pounds.

I wouldn't consider the new engine as having a high specific power output, but I would consider the old engine as being laughably low. It was fine when it came out, but to continue using it until 2006 was a joke.

Regarding specific output generally, if you've designed the engine properly, there's no reason for it to be unreliable regardless of the specific output. It's not a measure of durability; as you increase specific output, you build the engine stronger to deal with increased loads.

I would argue the the LSX is not the best engine in production today, but that's not important (It is a good engine though). The reason for the high fuel economy is that the engine has enough torque to cruse at ~1,400 rpm. This low rpm high throttle opening is the most efficient operation condition of a engine. The reason the torque and hp are high is that it's a large displacement engine. The smoothness is also related to this. It's a V-8, which is perfectly balanced, and the large rotating mass contributes to smooth operation. As previously discussed, the reliability is more a function of the design, not the specific output.

Slightly off topic, but still apropos...

My 13 year old son has decided he wants a Jeep (Wrangler/CJ style) as his first car. The reason this comes up now is that he is going to refurb one that has been neglected. I have done plenty of motor work, but I know nothing about Jeeps. Any inputs on years/engines to avoid/look for? Stuff like the pros and cons you guys have for the inline 6. Also, if anyone has a cheap one needing some work they want to unload, let me know. I am not a big fan of body work from a crash though, so lets avoid that if we can...

Go with something with the I-6, aside from the oil leaks it's likely to have, it's reliable. The older 4 speed automatic transmissions are weak, so get the manual if you can. If it came from somewhere they salt, check for rust. You could put a finger through the bottom of the rocker panels on my XJ as they were so rusted.

[Aaron]

Regarding specific output generally, if you've designed the engine properly, there's no reason for it to be unreliable regardless of the specific output. It's not a measure of durability; as you increase specific output, you build the engine stronger to deal with increased loads.

I would argue the the LSX is not the best engine in production today, but that's not important (It is a good engine though). The reason for the high fuel economy is that the engine has enough torque to cruse at ~1,400 rpm. This low rpm high throttle opening is the most efficient operation condition of a engine. The reason the torque and hp are high is that it's a large displacement engine. The smoothness is also related to this. It's a V-8, which is perfectly balanced, and the large rotating mass contributes to smooth operation. As previously discussed, the reliability is more a function of the design, not the specific output.

While specific output obviously isn't a measure of how durable an engine will be, it is a factor that plays into it. For example the S54 BMW M3 engine from the E46 was 333hp from 3.2L, and saw an 8,000rpm redline. This engine was plagued with bearing failures early on as a result from the poor design. These same bearings proved to last a lifetime at 6,000rpm in the other BMW I6 engines. The increased RPM caused the failure, and the reason for the increased RPM? So that the engine could have a high specific output.

What is the best production automobile engine today then? You won't find one that is as versatile as the LSX. And yes the reason for the good mileage is the low cruising RPM, but that's another advantage of the low specific output, because a high specific output engine needs high RPM to make that power, which means it will not perform well off-idle.

In the LSX, there is no downside to the low specific output.

[grim]

You would drop you oil pan and remove the bearing caps every 3 months? Sounds awful.

When you take a jeep you bought in Colorado then drive it to VA and go mudding or driving on the beach every weekend for 4 year you have to do this and a whole lot of other things to keep it from being destroyed from corrosion.


I rebuilt the entire block after only having it in VA for a year because i punctured the oil pan and got metal in the block. I unlike a lot of jeep owners beat the shit out of my jeep for my enjoyment. Thusly the purpose of lifting it and getting bigger tires, it wasn't for show it was to get places others cant.

[Penadam]

While specific output obviously isn't a measure of how durable an engine will be, it is a factor that plays into it. For example the S54 BMW M3 engine from the E46 was 333hp from 3.2L, and saw an 8,000rpm redline. This engine was plagued with bearing failures early on as a result from the poor design. These same bearings proved to last a lifetime at 6,000rpm in the other BMW I6 engines. The increased RPM caused the failure, and the reason for the increased RPM? So that the engine could have a high specific output.

What is the best production automobile engine today then? You won't find one that is as versatile as the LSX. And yes the reason for the good mileage is the low cruising RPM, but that's another advantage of the low specific output, because a high specific output engine needs high RPM to make that power, which means it will not perform well off-idle.

In the LSX, there is no downside to the low specific output.

http://en.wikipedia.org/wiki/Ward%27s_10_Best_Engines



The new 3.6 was on the list for 2011.

The Audi 2.0L has been on there forever; I think it's one of the best engines on the road today.

RE the M3 engine, it's clear the bearings weren't properly designed for that service. If they just used bearings designed for a life at 6k rpm and put them in service at 8k rpm, of course they're going to have problems. Look at the Honda S2k, 9k rpm, no huge reliability problems.

And high specific output doesn't always mean high RPM. The aforementioned 2.0L maintains peak HP from 4,300-6,000 and peak torque from 1,500-4,200. I'd say that's good off idle performance.

When you take a jeep you bought in Colorado then drive it to VA and go mudding or driving on the beach every weekend for 4 year you have to do this and a whole lot of other things to keep it from being destroyed from corrosion.


I rebuilt the entire block after only having it in VA for a year because i punctured the oil pan and got metal in the block. I unlike a lot of jeep owners beat the shit out of my jeep for my enjoyment. Thusly the purpose of lifting it and getting bigger tires, it wasn't for show it was to get places others cant.

True. Tearing apart the engine every 3 months is way more work than I'd want to do. More power to you for keeping it alive that long.

[grim]

True. Tearing apart the engine every 3 months is way more work than I'd want to do. More power to you for keeping it alive that long.

Kept it running for 7 years then i had a kid

[Jdmluvr]

What is the best production automobile engine today then? You won't find one that is as versatile as the LSX. And yes the reason for the good mileage is the low cruising RPM, but that's another advantage of the low specific output, because a high specific output engine needs high RPM to make that power, which means it will not perform well off-idle.

In the LSX, there is no downside to the low specific output.

I don't know if I'd give the LS that much credit. Whats the point of rolling around with 400hp if you can't use it to its full potential in like say a vette. Those engines pop like the old WRX "glass" trannys. I'm not a GM professional, I'm just speaking from a street mechanic point of view. Now it's different when your talking about using it in a truck because it will almost always be used in a low rpm range. You'll have the power,torque, and nice highway cruising rpm.

[age315]

[QUOTE=dragos13;648110]Trail Damage is a great site. Last year we put together a couple threads here on the forum. Tons of great places to go wheelin


Damn Casey you go and don't invite me? Haahahaa. I try and go when ever I can so I'm always down to go. I've got an 06 wrangler unlimited lifted on 33's. It's the last year of the great I6 before the mini van 3.8 v6.

[modette99]

I bought the Jeep GC to off-road, really need a lift kit. But the thing is once out on any trail the slow going drives me nuts. You see very little in a day int he Jeep on a trail. However I see 200+ miles of dirt when on the Dual Sport motorcycle.

So although I have talked about the 6" lift, I'm thinking the 2" as I'm not sure how much I will actually 4x4. Although that 6" will make replacing the front diff bushings down the road again a breeze.

[Penadam]

Got a new Grand Cherokee as a rental this past week, drove it along I-8 east from San Diego. Did well over the mountains, had plenty of power to go from sea level to 5,000 feet. Great leaving stoplights, builds revs quickly and the AWD makes it drama free. Little raspy and sounds slightly unrefined, but smooth all the way to redline. Had it for a week, and averaged around 23 mpg with mostly 70mph driving over mountains. All in all pretty impressed with the engine, and very impressed with the Grand Cherokee. We had a stripped down version, but it was still pretty nice. I bet the loaded ones are sweet.

[Aaron]

I lucky to get half that gas mileage.

[mdub]

sounds like ya guys need to migrate onto a jeep forum..

[Aaron]

How dare you talk about something not motorcycle related in the middle of winter!

[mdub]

hahahah....yes....especially here....need admin to delete this thread....