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Unread 10-25-2013, 08:32 AM   #1
MoMatt
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Sad V8

Here's what I learned about my new-to-me WJ yesterday:









Bought it with the idea that it needed a new head gasket - looks like it'll need that, plus a new engine!

The engine was full of water everywhere, so something caused the head or head gasket to go - but I'm scratching my head on what caused this piston to melt!

The valve in the picture is frozen - but looks to be in tact.

Anyways - at a crossroads about whether to rebuild this one or find a used engine to throw in there. This one only had 118k on it.

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Unread 10-25-2013, 11:09 AM   #2
MattJeep
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Looks like neglect and oil burning for awhile. Sometimes burning coolant for a time will actually steam clean that chamber. Not so on yours. I'd only do a used 4.7 if it was really cheap and/or good history. Otherwise, too much of a pita to do it twice.
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Unread 10-25-2013, 12:19 PM   #3
MoMatt
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Yeah, I was pretty surprised when I pulled the head off to see that!

Used 4.7's don't come cheap but I'm thinking that is the best way to go - I plan to be patient in finding the right one.

The rest of the truck seems to be in good shape and this forum has plenty of information on it to help me put it all back together.
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Unread 10-25-2013, 12:30 PM   #4
alfaitalia
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What are the bores like? I would rebuild it if they where ok.

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Unread 10-25-2013, 12:59 PM   #5
MoMatt
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Bores look ok, but I just don't like the prospect of the thing turning into a money pit if a rebuild goes bad.
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Unread 10-25-2013, 03:05 PM   #6
coopdc78
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I'd rebuild it. You never know what u get .. You may get another pike of junk engine
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Unread 10-25-2013, 04:55 PM   #7
WJHahn
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I recently swapped in a reman from Marshall. 3 Year, unlimited mile warranty. Bought it off Rockauto with a coupon code that covered shipping. Total was right around $2200 IIRC.
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Unread 10-25-2013, 06:04 PM   #8
MoMatt
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WJHahn, found that long block on Rock Auto, MUCH cheaper than any other remans I've seen, thanks!

ALSO! While looking at that, I found this:

http://www.rockauto.com/info/ATK/For...ningGasket.pdf

Which shows a picture of a melted valve seat insert - looks nearly identical I'd say to my cylinder head! So maybe that is all that happened to my engine and I just need a top end after all. I saw the melted metal and thought for sure I'd need at least a new piston / bearings which would involve a lot more than just heads.

Anyone else agree? Look at the fourth picture I posted and compare it to the first picture in the pdf - look pretty similar?

Maybe I'll attempt a rebuild after all.
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Unread 10-26-2013, 05:53 AM   #9
car5car
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I see a broken piston, what is a big deal, replace piston.
Is valve bent?
Lap valves.
What is frozen valve? Stuck to valve guide? Get some bolt and punch it out! Use grease on bolt to prevent guide scratching. Spray PB blaster in guide. I don't think guide has to be replaced.
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Unread 10-26-2013, 08:44 AM   #10
Cirruslydakota
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I would at least get the heads checked at a machine shop. The 4.7 loves to drop valve seats so look into getting those replaced. After all, you already have the heads off so you might as well do preventative maintenance.
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Unread 10-26-2013, 10:55 AM   #11
Jeeples
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Quote:
Originally Posted by Cirruslydakota View Post
I would at least get the heads checked at a machine shop. The 4.7 loves to drop valve seats so look into getting those replaced. After all, you already have the heads off so you might as well do preventative maintenance.
That's what the PDF he linked to addresses. Basically it just reiterates what most of us here know, overheating can lead to dropped valve seats in the 4.7.

OP at the very least have the cylinder heads rebuilt and resurfaced.
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Unread 10-26-2013, 12:20 PM   #12
WJHahn
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And..compare the costs to having all the work done to the reman. That's what I did and the difference didn't make it worth getting all the work done and having a bottom end with all the miles on it. If you can just get the top end done for much cheaper and are comfortable with the bottom end then go for it, otherwise if the price is close I would (again) go for the long block. Just my $.02 Wish you well with whatever path you take.
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Unread 10-26-2013, 01:37 PM   #13
car5car
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Replace piston, hone cylinder.
remove valves, lap them to check
put head upside down and fill combustion chambers by ATF or diesel fuel to check leaking valves.
Buy expensive 20" aluminum level from Home Depot and check head warpage.
http://www.homedepot.com/p/Empire-24...3#.UmwZ0nB2G0I
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Unread 10-26-2013, 02:39 PM   #14
Pierre_r
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Does it have aux light infront of the grille or anything else that blocks airflow?

Because on the earlier models of the WJ the cooling system is not capable of doing its job if even a pair of lights block the airflow.
Then it will always overheat a little and at the end a valveseat wil drop in to a cylinder and do that to the head and piston.

Here in sweden its really common to find early WJ with trashed engines since almost everyone that got here had a brushguard and aux lights added to it.
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Unread 10-26-2013, 03:00 PM   #15
Thomahawk
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Never heard of before, and around here we also got lots of 99/00 with Cobra bull bar with lights, never seen them brake down, or due to That,

I mounted my 5or6" hella's behind the grill, didnt affect the temp a tad, and the fact That they overheat in Skandinavia Are not very high, we have 6months Winter, and in. Summer it nearly Max out at 25-30deggre C/77-86F

What Are Those actuall changes in the cooling system, fan setup?

Just saying, first time heard, never seen it, but i might be wrong.
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