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  #25  
Old 03-28-2012, 08:47 PM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

Hey Joe,
Without seeing the bearings and crank I'd only be guessing, so take it for what it's worth....
There are about a half dozen reasons big end bearings fail. They range from improper machining of the parts, improper assembly, normal high mileage use, lack of lubrication, and debris in the oil.

Since you had an 05'? I think it's safe to assume it wasn't machining or assembly and you didn't state your mileage (that I recall, but I'm old) but unless you were 200k+ we can probably rule that out as well.

So, the two things that come to my mind are debris in the oil and lack of lubrication. Both of these are pretty easy to spot on a bearing surface. Debris in the oil makes the bearing surface look rough or scored. You can see depressions or grooves on the inner surface where the crank rides. Lack of lubrication deforms and discolors the bearing and crank. Almost like it smooshes the bearing, changing the color slightly and sometimes even makes it "shiny".
Again, both of these are two totally different looks for failure.

Debris in the oil is very likely especially if your running something like a K&N filter. Even changing the oil at specified intervals. If you drive a lot in dusty conditions and that dust gets into the oil it doesn't take much to mess up the bearings. It's even more likely if you drive "hard" in dusty conditions due to the oil filter going into bypass and allowing oil to circulate unfiltered more often for short periods of time.

OR.....It could have just been one of those days where the planets, moon, and stars aligned against you and something just decided to "let go"....It happens...

I don't know for sure about the 4.7 as I've never had one apart, but some motors you CAN replace the bearings with the motor still in the car. It's not the "best" way (and kinda "backyardish" if you ask me), but we've done a few bearing replacements in some high mileage trucks just to buy the owner some time before buying something new.

So the big questions now since you sold the WK is....Whatcha gunna buy now?!?!
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  #26  
Old 03-28-2012, 08:49 PM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

Oh, I asked about the oil weight because I still have my own "opinion" on why Jeep decided to change the spec on all their gas motors from 5-30 to 5-20...but that's another topic for another time and likely not anything to do with what happened to your motor....
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  #27  
Old 03-29-2012, 12:07 AM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

I'm going to buy an 07 Hemi Overland with Quadra Drive II...there are a ton out there. I'll wait 6 months then pick one up. Probably silver...get the superlift...it's my dream rig. I thought about the 08 but I decided against it.

Now...since thats cleared up why did they switch to 5w-20? Is it better/worse than 5w-30?
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  #28  
Old 03-29-2012, 01:43 AM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

why the 07?
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  #29  
Old 03-29-2012, 07:20 AM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

Quote:
Originally Posted by socalwk View Post
I'm going to buy an 07 Hemi Overland with Quadra Drive II...there are a ton out there. I'll wait 6 months then pick one up. Probably silver...get the superlift...it's my dream rig. I thought about the 08 but I decided against it.

Now...since thats cleared up why did they switch to 5w-20? Is it better/worse than 5w-30?
Nice! Ever try a CRD?

5-30 vs. 5-20 will be debated til probably the end of time. Personally, I feel the 5-20 oil was only brought in for Cafe ratings as well as for the hemi to make the MDS system function easier. 5-30 oil is a "better" fit for the 3.7/4.7 motors but Jeep didn't want multiple weights of oil sitting around....especially since the difference between 5-20 and 5-30 is pretty small.... Again, personal preference...

Good Luck Joe!
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Old 03-29-2012, 12:08 PM
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  #31  
Old 03-29-2012, 03:18 PM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

Not really worried about online rep....most people misrepresent online anyway. Lol. I'm just a normal dude going through the grind.

The 07 because I'm not to keen on the fly by wire throttle control in the 08 and up. Plus the price is right.
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  #32  
Old 03-29-2012, 03:22 PM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

I believe all of the Hemis are drive-by-wire for the throttle control...unless there is something specific about the '05-'07 you prefer...
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Old 03-29-2012, 05:23 PM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

Really? I didn't know that.

I thought I had read on wkjeeps that fly by wire wasn't introduced until the 08 model year.
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Old 03-30-2012, 02:13 AM
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Quote:
Originally Posted by socalwk View Post
Really? I didn't know that.

I thought I had read on wkjeeps that fly by wire wasn't introduced until the 08 model year.
On the 4.7 and 3.7 the hemi was always fly by wire.

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Old 03-30-2012, 10:37 AM
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Re: 05 4.7L V8 Engine Dead: Replacement Advice

Ahhhh...okay. That makes sense. Well I guess now it comes down to can I get a deal on an 08 in about 8 months....wonder what I can nab one for.
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