2.5 rebuild...this should be fun - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 2.5 rebuild...this should be fun

Jeep Grand Cherokee Headlight AssembliesJeep Wrangler Wheel Bearing & Hub - FrontPremium LED Lighting by VISION X, Proudly sold at ROCKRIDG

Reply
Unread 01-18-2013, 09:57 PM   #1
LJameson
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: Elizabeth Lake, CA
Posts: 3,746
2.5 rebuild...this should be fun

So about a year ago I bought a 1990 YJ for a really good price. The body was super clean, only had 100,000 miles on it, and like I said, I got a smoking deal on it. It originally came from Canada and was treated with Ziebart, and it seemed to have worked because they only rust it has is some minor surface rust on the frame, and a little tiny spot on the rocker.



The only problem was, I knew the engine was a little tired. The kid I bought it from neglected it severly. Oil was 2 quarts low and very very black (think of the oil that comes out of a diesel), thermostat housing leaked and was low on coolant so it was overheating. But I drove it and it felt fairly strong for a 2.5. In fact, I took it over the Grapevine (a steep grade on the I5 for all you non-socal people) and it maintained 70. Granted, that was foot to the floor in 4th, but I thought that was normal for a 4 cyl Jeep since my old 88 Toyota pickup could barely do 65 on the same hill with a fresh 22RE. So I put fresh fluids in it all the way around and fixed the leak and left it alone otherwise.

Fast forward to a few weeks ago I decided to do a compression check on it just out of curiosity. Well, that was a bad idea. :

Cyl 1: 90 psi
Cyl 2: 110 psi
Cyl 3: 125 psi
Cyl 4: 70 psi

Balls. This engine was more tired then I thought. Cyl 4 is practically a dead hole and the other 3 aren't much better. jOur engine guy was with me and was amazed that it ran smoothly. No misfires or anything, and the fact that it ran somewhat strong. So I went to the parts counter and had a long block priced for me thinking that it might not be too much with my employee discount. Well, lets just say that Chrysler is proud of them. I drove the jeep home, pulled it into my garage and yanked the motor out:



Took me about an hour. Pretty easy to do when your Jeep is the most base model you can get. I loaded the engine into the truck and hauled it down to work where I would tear down the motor and see what needed to be done to have this thing running like new again.





As you can see this things been apart before and has had a new head put on. My guess is it blew a head gasket. The bottom end hasn't been touched and still has all the factory parts in it. Things were looking bad. I got the head off and found massive ridges worn into the cyl walls from the rings. I tried taking pics but they just would not show how bad they were, I could drag my finger nail across and actually have to move my finger back to get across it. The cam lobes were worn down severely, bearings were toast and the crank was scored:



I could tell this things been ran out of oil and overheated several times. It was abused bad. Everybody in the shop could not believe it was running, especially how well it was. It didn't knock, make any noise or blow any smoke out of the tail pipe. Even my oil pressure was at 20 psi hot idle. Our engine guy said "I know those 2.5s are tough little ****ers, but DAMN! I have more respect for them than I already did. I'm shocked this thing even ran, it's the worst engine I've ever seen."

It's funny, all the parts outside the engine have the pentastar casted into them because it's a "Chrysler." But as I was looking at all the parts inside the engine, there was no hiding that it was pure AMC:



After I got it all torn down I took the bare block and crank to the machine shop to see if the it's salvageable. The conversation with the machinist went like this:

"HOLY CRAP! Did you get this out of a junkyard car?"
"Nope, it came out of my Jeep"
"Ah, so it just kicked the bucket and you pulled it"
"Not really, It was actually running fairly good. No smoking or knocking"
"BS, this is one of the worst shapes I've ever seen. I don't think I've ever seen a cyl ridge so big.:
My Co-worker that went with me: "No, I can vouch for him. It actually ran pretty damn good."
Machinist

He called me later that day after he measured everything. The cyl were worn .040'' over! The crank was at least straight and they could grind it .010'' under. So he said he could bore it .060'' over since the cyl walls are really thick on those motors and I wouldn't have a problem. I gave him the ok to clean the block, bore it .060 over, line hone the crank journals, grind the crank, size the rod and main bearings and install new .060 over pistons onto the rods. A week goes by and he calls me up and says its all done. I get there and looked for my stuff and couldn't find it. He points right next to me and there it was, I couldn't even recognize it. A pretty virgin metal block with freshly honed cylinders, smooth clean crank and shiny new pistons on my rods. I took it all back to the shop and set the pretty block on my cart. All my co workers saw it and was amazed that the greasy pig that I had apart was the same block that was sitting there.



Oooohhhh, prettyyyyy:



The first thing I did was get a new oil filter stud from our parts dept. As you all know, the AMC-era YJ's used metric thread oil filters. Well, for some reason they're hard to find around here and only one parts store carries them. Chrysler doesn't make them anymore and they only have one left in stock at some dealer in Arizona. So I got an oil filter stud from parts and slapped it on. Now I can run the standard thread filters, such as a Mopar M090 used on 4.0s and newer 2.5s, which we carry in stock.



I got the pistons, crank and cam in today. On monday I'm going down to a place called The Cylinder Head Exchange and swapping my current head for a new one. Once the engines all together I'll paint it and throw this beast into my Jeep.



__________________
"Anything to do with the land, I love."
"So it's probably eighty percent luck and twenty percent skill."

-Chris LeDoux

I never could figure what the sky was thinking, but the soil, she don't keep too many secrets.
LJameson is online now   Reply With Quote
Unread 01-18-2013, 11:11 PM   #2
CRASHNDENT
Registered User
1994 YJ Wrangler 
 
Join Date: Jul 2008
Location: Poulsbo, WA
Posts: 297
NICE, i'll be following this one.
__________________
tn-1.jpg
CRASHNDENT is offline   Reply With Quote
Unread 01-19-2013, 07:44 AM   #3
EABiker
Registered User
1989 YJ Wrangler 
 
Join Date: Dec 2004
Location: Frederick, MD
Posts: 1,671
It sure helps to have a nice place to work on that, doesn't it!

Now paint it Chevy orange, and tell em you swapped in a 350!
EABiker is offline   Reply With Quote
Unread 01-19-2013, 07:55 AM   #4
Xpress
Registered User
1989 YJ Wrangler 
 
Join Date: Dec 2010
Location: The Great Big Box, California
Posts: 5,805
Paint it red because red Jeep.

Looking good!
__________________
[url=http://www.jeepforum.com/forum/f12/another-5-2l-yj-thread-1503048/][FONT="Arial Black"][COLOR="Lime"][SIZE="4"]My 5.2L Build thread[/SIZE][/COLOR][/FONT][/url]
-1989 Jeep Wrangler 2.5L, soon to be 5.2L
-1996 Jeep Grand Cherokar 5.2L, donor and rainy day driver
-2004 Kawasaki KLR650 sunny day driver
[QUOTE=mudsweatNgearz;21162729]Leave em off and weld an I beam on. Bumperetts just scream homo.[/QUOTE]
"A well regulated Militia, being necessary to the security of a free State, the [B][I]RIGHT[/I][/B] of the people to keep and bear Arms, [B][I]SHALL NOT BE INFRINGED[/I][/B]."
Xpress is offline   Reply With Quote
Unread 01-19-2013, 08:12 AM   #5
SeanB95YJ
Registered User
1995 YJ Wrangler 
 
Join Date: Nov 2009
Location: Schenectady, New York
Posts: 1,185
.060" over????

no longer 4 squirrels... now you've got 4 gophers

anything special with the valvetrain? bigger valves? cam? roller? figured since you're doing a complete rebuild & going with larger bore out of necessity you might upgrade the upper end to match.
__________________
[FONT="Comic Sans MS"][COLOR="Blue"]Sean B. - Schenectady, NY - 95 YJ, 350/700r4/NP241, JB Shorty SYE, 8.8 rear, 2" BDS, 1" homebrew shackles, Daystar 1" BL, TJ flares, 35x12.50 General Grabber AT2 on 15x10 Bart D-Truckers, Polyshield polycarbonate windshield, HD over/under crossover steering
[/COLOR] [COLOR="Red"]swap/build thread: [url]http://www.jeepforum.com/forum/f22/after-almost-4-years-finally-my-own-build-swap-thread-1542284/[/url][/COLOR][/FONT]
SeanB95YJ is offline   Reply With Quote
Unread 01-19-2013, 08:33 AM   #6
CrawlingForward
Rookies Happen.
 
CrawlingForward's Avatar
1995 YJ Wrangler 
 
Join Date: Nov 2008
Location: Brazoria, Texas
Posts: 2,294
Sub'd!

Great thread for those of us still learning!
__________________
My Other Jeep Is A Jeep - Crawlingforward's Jeep-Related Adventures

95 YJ, Rio Grande - The Wannabe Sleeper Wheeler
2010 JKU, Islander Edition - The Burly Stock Overlander

- North Shore Jeep Club -
Build/Wheel/Break/Educate/Upgrade/Repeat
CrawlingForward is offline   Reply With Quote
Unread 01-19-2013, 12:08 PM   #7
LJameson
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: Elizabeth Lake, CA
Posts: 3,746
Quote:
Originally Posted by EABiker View Post
It sure helps to have a nice place to work on that, doesn't it!

Now paint it Chevy orange, and tell em you swapped in a 350!
Quote:
Originally Posted by Xpress View Post
Paint it red because red Jeep.

Looking good!
Thanks guys. We actually have a whole case of street hemi orange engine paint in out parts room. I'm seriously considering it. Why? Because racecar.

Quote:
Originally Posted by SeanB95YJ View Post
.060" over????

no longer 4 squirrels... now you've got 4 gophers

anything special with the valvetrain? bigger valves? cam? roller? figured since you're doing a complete rebuild & going with larger bore out of necessity you might upgrade the upper end to match.
I searched high and low looking for a more aggressive cam and the only one I found was the hesco cam. But that was out of my budget. I might do roller rockers, but ill see how it all pans out.
__________________
"Anything to do with the land, I love."
"So it's probably eighty percent luck and twenty percent skill."

-Chris LeDoux

I never could figure what the sky was thinking, but the soil, she don't keep too many secrets.
LJameson is online now   Reply With Quote
Unread 01-19-2013, 09:27 PM   #8
LJameson
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: Elizabeth Lake, CA
Posts: 3,746
Well, it's been pretty cold up at my house recently, so it makes it hard for me to want to work on my jeep when it's 30 degrees outside. I decided to load my jeep up onto a trailer and tow it to my dads house where its a little bit warmer. While it's there I'll pull off the fenders and grill, bust out the pressure washer and clean the engine compartment. While I have those off, I'm going to clean the front section of the frame a little bit by getting rid of the surface rust and painting it.
__________________
"Anything to do with the land, I love."
"So it's probably eighty percent luck and twenty percent skill."

-Chris LeDoux

I never could figure what the sky was thinking, but the soil, she don't keep too many secrets.
LJameson is online now   Reply With Quote
Unread 02-01-2013, 09:27 PM   #9
LJameson
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: Elizabeth Lake, CA
Posts: 3,746
I decided to take the fenders off my jeep and use my dads pressure washer to blast all the Ziebart off the frame. Took the fenders off, pressure washed it, cleaned with wire brush and sprayed rust encapsulator on it.




Meanwhile at work I've been trying to squeeze some time
after work to work on the motor. I got the head bolted on and started painting the block.




Luckily I have tomorrow off. Hopefully ill be able to finish the motor and start prepping the rest of the jeep.
__________________
"Anything to do with the land, I love."
"So it's probably eighty percent luck and twenty percent skill."

-Chris LeDoux

I never could figure what the sky was thinking, but the soil, she don't keep too many secrets.
LJameson is online now   Reply With Quote
Unread 02-01-2013, 11:21 PM   #10
cstone94
Registered User
1995 YJ Wrangler 
 
Join Date: May 2011
Location: Martinsville, VA
Posts: 725
This makes me want to pull my motor and bore it! I've got 210,xxx on my 4 squirrels!
__________________
95' YJ - Warn Bumpers/Tire Carrier/Winch - 2.5L - 6" Skyjacker Suspension Lift - 4.10's - Locrite Locker - Dana 35/30 - 35" BFGoodrich KM2's

11' F250 - DD

1982 Toyota Pick-Up - Spray-On Yellow Rhino Lined - Chevrolet 305 H.O. - SM465 - NP208C - All-Pro Off Road 5" Springs - 35x15.50x15 Super Swampers
cstone94 is offline   Reply With Quote
Unread 02-02-2013, 08:25 AM   #11
smithj156
Registered User
1993 YJ Wrangler 
 
Join Date: Jan 2013
Location: pass chirstian, MS
Posts: 13
makes me want to tear mine down maybe next winter its geting warm in the south so its time to start wheelin
smithj156 is offline   Reply With Quote
Unread 02-02-2013, 08:33 AM   #12
michaelleegarre
Registered User
2000 TJ Wrangler 
 
Join Date: Jun 2009
Location: kentucky
Posts: 184
I would like to know the hp gain
__________________
Michael Garrett
1987 YJ - sold, 1995 ZJ - sold, 1998 XJ - sold, 2000 TJ
michaelleegarre is offline   Reply With Quote
Unread 02-10-2013, 05:32 PM   #13
LJameson
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: Elizabeth Lake, CA
Posts: 3,746
Been slowly picking away at getting this thing back together. I've been slammed at work lately and trying to squeeze in some time to work on the engine has been tough. But, its almost there. I got the freeze plugs in, new timing chain on, rocker arms installed, oil pressure sending unit installed, new water pump and thermostat, intake manifold on and put on a new exhaust manifold...




When i was tearing down the engine, i found the EGR tube was cracked right where it meets with the flange on the exhaust manifold. It was surprising to me because I didn't hear an exhaust leak, but then I saw that someone welded a washer inside the flange and filled up the hole so it wouldn't leak, instead of just replaceing the tube. I thought "great, theres no way im going to find another one." No junkyards had it, no aftermarket company makes it and being that in 91 Jeep got rid of the EGR system all together with the MPI 2.5s, I thought theres no way that Chrysler would have any...

I couldn't have been more wrong. I had our parts manager look up to see if there was any dealer that had one lying around or maybe there was one lying around in one of Chryslers parts warehouse. Well, it turns out that theres 244 of them in stock at our LA warehouse. So I told him to get it and I had it the next day. Now all I'm waiting for is the timing chain tensioner to come in, then slap on the cover, oil pan and rear main seal and then this 2.5 liters of AMC fury is ready to make even the most potent muscle cars tremble in their fear.

__________________
"Anything to do with the land, I love."
"So it's probably eighty percent luck and twenty percent skill."

-Chris LeDoux

I never could figure what the sky was thinking, but the soil, she don't keep too many secrets.
LJameson is online now   Reply With Quote
Unread 02-12-2013, 11:08 AM   #14
LJameson
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: Elizabeth Lake, CA
Posts: 3,746
ENGINE IS DONE!



Now I'm just getting the jeep ready for the motor.
__________________
"Anything to do with the land, I love."
"So it's probably eighty percent luck and twenty percent skill."

-Chris LeDoux

I never could figure what the sky was thinking, but the soil, she don't keep too many secrets.
LJameson is online now   Reply With Quote
Unread 02-12-2013, 11:36 AM   #15
michaelleegarre
Registered User
2000 TJ Wrangler 
 
Join Date: Jun 2009
Location: kentucky
Posts: 184
Once you get it back in let us know if their is a hp gain might need to take out my little 2.5
__________________
Michael Garrett
1987 YJ - sold, 1995 ZJ - sold, 1998 XJ - sold, 2000 TJ
michaelleegarre is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.