The 4.0... - Page 2 - 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 > General > General Discussion > The 4.0...

Huge Soft top SaleSYE Kits from CCOR! 706-207-4140SALE PRICING, Specials, Huge Savings Alloy USA and Posi-Lo

Reply
Unread 04-04-2012, 09:36 PM   #16
andy_mitch92
Registered User
1977 CJ7 
 
Join Date: Jun 2008
Location: Great Bend, KS
Posts: 580
Quote:
Originally Posted by JFranko

They were putting a 4.2L in the trailblazers up until they stopped making them. I drove one for about half a year and really liked it. It was pretty quick for a big SUV (270hp 275 ft/lbs of torque). My mom owned it for 10 years before me and we never had any problems with the engine. It was also on Ward's 10 best engines list for a few years.
I was reading the other day that it was designed to be turbo charged. Think of the power it could make with some boost.

andy_mitch92 is offline   Reply With Quote Quick reply to this message
Unread 04-05-2012, 07:03 AM   #17
Chris_
Registered User
2002 TJ Wrangler 
 
Join Date: Apr 2005
Location: TX
Posts: 2,225
I had a Ford 4x4 truck with the I6 when I was in high school. It was a 4 speed with a granny gear, and had 5.13 gears. It had a twin, and they were special order farm trucks. It would pull a house off the foundation, but it would barely do 65mph going downhill with a tailwind. My XJ I6 ran great with 200k on it, and my Wrangler I6 will do the same. The GM 3800 V6 is another motor I've used, and it would run forever.
__________________
'02 TJ X Apex Edition
'00 XJ Sport
Chris_ is offline   Reply With Quote Quick reply to this message
Unread 04-06-2012, 12:57 PM   #18
Azzy
Web Wheeler
 
Azzy's Avatar
1996 XJ Cherokee 
 
Join Date: Sep 2010
Location: Finleyville
Posts: 3,211
Ive been reading up on the later XJ 4.0's... the same ones used in the later Grands and TJ's. Turns out after those years, the engines have a pretty fatal flaw.

http://pgh-offroad.com/forum/showthr...w-someone-good

Quote:
My hypothesis is two fold;
1)the pistons are different from 96-ish/97 although internal specs are the same. I think they went with a cheaper casting which leaves the piston inheirently weaker. Some of early powertechs didn't have teflon coating on the skirt, those that did they weren't as far down on the skirt as the others. Weaker piston/skirt material, with less/no teflon coating means more friction on a weaker material.

2) Now add in that misfire detection isn't the greatest (Im getting long winded as usual so I am not going to go into detail)
2a)and that CMP and CKP sensors tend to fade in and out on without going completely out of spec- just living on the hairy edge of the outer limits t on our rigs and only then ultimately going gonzo.

This all meaning the revolution algorythm of the misfire detection prgram gets eronious data, doesn't set a light/dtc when there is a misfire and you keep motoring on unitl CMP/CKP come back into range or you feel a dead miss that the PCM didn't detect and mitigate.

This all allows a misfire to go undetected straining the weaker pistons, until the skirt cracks, then it splits, then it chunks out, then it goes gonzo.

Thats just my theory.... nothing other than pure talking out of my arse. I came to that plausable explination after talking with a handful of customers and hearing similar stories no light, good verified service history, etc. Coupled with a handfull of my rigs, and engine work on the side- and talking to Bob @ ICS who agrees, and he seems to seen alot of them too go out that way.


Of all the cracked skirt 4.0/2.5s I have brought back to life with replacing cracked skirts with improved pistons and honing or boring if need be; I never had one come back and to the few I keep in touch with have gone 50 60 80K since my engine work without issue.
__________________
ADW - Custom gauges, decals, and now laser engraving. Check out the gallery here.
Azzy is offline   Reply With Quote Quick reply to this message
Unread 04-06-2012, 02:04 PM   #19
Millermagic
Registered User
2000 XJ Cherokee 
 
Join Date: Apr 2007
Location: Syracuse, New York
Posts: 1,910
Friend of mine drove his a few hundred miles with a broken piston skirt. From what we could tell, the block was fine and it would just need a new piston.
__________________
2000 XJ - 3.5'' Lift & Skinny Mudders.
Previous: A CJ, Few TJs and JK.
Millermagic is offline   Reply With Quote Quick reply to this message
Unread 04-06-2012, 02:30 PM   #20
Tom95YJ
[] Eye'd Jeep Connoisseur
 
Tom95YJ's Avatar
1999 XJ Cherokee 
 
Join Date: Sep 2004
Location: Salt Lake City, Utah
Posts: 8,398
Ford 4.9's
AMC 4.2L
Jeep 4.0L

All indestructible work horses IMO they should have never done away with them !
__________________
'89 YJ The Smurf Build Thread
'99 XJ Black Betty Build Thread
Tom95YJ is online now   Reply With Quote Quick reply to this message
Unread 04-07-2012, 12:17 AM   #21
00xj54
Registered User
2000 XJ Cherokee 
 
Join Date: Oct 2005
Location: San Diego
Posts: 1,442
Quote:
Originally Posted by Tom95YJ View Post
Ford 4.9's
AMC 4.2L
Jeep 4.0L

All indestructible work horses IMO they should have never done away with them !

What did they put the AMC 4.2Ls in?
__________________
[I]00' XJ Sport. 4.0 I6.
[B]|15" Canyon Crawlers | 30x9.5 Bridgestone Dueler A/T Revos | [Lifted (2" Teraflex Spacers | 2.5" RE AAL | Edlebrocks IAS)| K&N Homebrew Intake | Flow Master 70 |Clear Corners/Side Markers| Class III Hidden Hitch | C4x4 Fronts Tow Hooks | JKS Discos | Surco Safari Rack | Hella 500s |
00xj54 is offline   Reply With Quote Quick reply to this message
Unread 04-07-2012, 08:19 AM   #22
Mickey_D
Registered User
1997 ZJ 
 
Join Date: Aug 2008
Location: 40 3'42.36"N 112 2'16.73"W, Utah
Posts: 6,757
Quote:
Originally Posted by 00xj54 View Post
What did they put the AMC 4.2Ls in?
CJ-5, CJ-7, first couple years of the YJ. I also believe they were a "fuel economy" option in the 2 door FSJ's.

The AMC 4.2L I-6 was pretty much universally known as the 258 cu in I-6. American Motors Company (AMC) were staunchly opposed to anything metric.
__________________
1997 ZJ 5.2 Orvis, Baby!
1953 Willys M100 trailer Tagalong
________________
[_][][][][][][][][_]


Mickey_D is offline   Reply With Quote Quick reply to this message
Unread 04-07-2012, 08:32 AM   #23
commodore_dude
Registered User
2006 LJ Wrangler 
 
Join Date: Oct 2003
Location: Alpharetta, GA
Posts: 1,224
The 4.0 in my XJ blew without any warning at 100k miles, never did get a satisfactory explanation but I presume it was just poor maintenance in the 70k miles before I owned it. So far the one in my LJ has been trouble-free for 45k miles (been getting an intermittent O2 sensor code for about a year, but that's hardly the block's fault).
__________________
2006 Rubicon Unlimited

1998 Buick LeSabre Custom
commodore_dude is offline   Reply With Quote Quick reply to this message
Unread 04-08-2012, 09:56 AM   #24
Azzy
Web Wheeler
 
Azzy's Avatar
1996 XJ Cherokee 
 
Join Date: Sep 2010
Location: Finleyville
Posts: 3,211
Quote:
Originally Posted by Tom95YJ View Post
Ford 4.9's
AMC 4.2L
Jeep 4.0L

All indestructible work horses IMO they should have never done away with them !
You ever look through the XJ forum? The 4.0 is tough, and can handle abuse, but it is far from indestructible.
__________________
ADW - Custom gauges, decals, and now laser engraving. Check out the gallery here.
Azzy is offline   Reply With Quote Quick reply to this message
Unread 04-09-2012, 04:08 PM   #25
89YJmoneypit
KMG365
 
89YJmoneypit's Avatar
1989 YJ Wrangler 
 
Join Date: Dec 2002
Location: Marseilles, IL
Posts: 1,003
Quote:
Originally Posted by Mickey_D View Post
American Motors Company (AMC) were staunchly opposed to anything metric.
Kinda funny considering they were in bed with Renault towards the end...
__________________
89 YJ
Transplanted '99 4.0, AX-15, NP231
Red Jeep club #8

97 ZJ Laredo
4.0, 42re, NP242
Was my daily driver, now son's college wheels.

Marseilles Fire Dept: http://www.flickr.com/photos/4461494...th/7659346164/
89YJmoneypit is offline   Reply With Quote Quick reply to this message
Unread 04-09-2012, 04:20 PM   #26
Balvar24
Registered User
1979 CJ7 
 
Join Date: Mar 2008
Location: Rock Ridge
Posts: 5,146
Quote:
Originally Posted by 00xj54 View Post
What did they put the AMC 4.2Ls in?
REAL Jeeps.
__________________
"Work hard, rock hard, eat hard, sleep hard, grow big, wear glasses if you need 'em."
Balvar24 is offline   Reply With Quote Quick reply to this message
Unread 05-13-2012, 09:50 PM   #27
jeepyj13
Registered User
1993 YJ Wrangler 
 
Join Date: Nov 2010
Location: greenville, mississippi
Posts: 1,796
Quote:
Originally Posted by Tom95YJ
Ford 4.9's
AMC 4.2L
Jeep 4.0L

All indestructible work horses IMO they should have never done away with them !
I agree. We had a 93 ford f150 with 4.9 with a 5speed connected to it and it was a torquer. I have the 4.0 in my yj and xj. My xj I put through hell, Ive overheated it on more than 1occasion, ran it low on oil once before, and my wheeling mostly consist of mudriding. Since my xj is stock with some walmart ats the skinny petal was my bestfriend and I stayed mashing on it. I had a old dodge dart with a slant 6 that was a dog, but that engine was tough too.
__________________
"Its a Jeeps World, other 4x4s just get stuck in it."
jeepyj13 is offline   Reply With Quote Quick reply to this message
Unread 05-14-2012, 12:37 AM   #28
RogueSpear2023
Registered User
2003 TJ Wrangler 
 
Join Date: Jun 2008
Location: Fargo, ND
Posts: 6,949
Jeep had a rough spot around 00-01 but since then they have been trouble free, and most of that was head, and manifold issues. I have an 03 with 85K on still runs great, my dad has 98 4.0L with over a 175K on it still running strong. These are both in TJs. The 05-06 TJs have OPDA issues.
__________________
Max

2003 Jeep Wrangler Rubicon
4.0L, 42RLE, Dual Tops, Full Doors, JKS Front Disconnects, Cragar Soft 8 Black Wheels, 33x12.5x15 Goodyear Duratracs, .75" Front Coil Spacers, Bushwacker 6" Flat Fender Flares, Skid Row Steering Box Skid, LubeLockers, Rubicon Locker Mod, OBA, Cobra 19 Ultra III CB, 3' Firestik, Rough Country 2.2 Steering Stabilizer, RC 1.25" BL, RC 1" MML, RC Grab Handles, Fog Lamp Bent Pin Mod, 4" Apline S Series Speakers, Kenwood Excelon 6.5" Speakers, 6.5" JL Audio 6W3V3 Subwoofer (in center console) w/MTX Thunder 202 amp, IPF H4 Headlight Housing, Sliverstar H4 bulbs.



TJ Tech Boot Camp
TJ Specs

"Buying a jeep and not taking it off road, is like buying a dragster and never taking it to the track"
RogueSpear2023 is offline   Reply With Quote Quick reply to this message
Unread 05-14-2012, 05:44 AM   #29
andy02
Registered User
2004 TJ Wrangler 
 
Join Date: Aug 2007
Location: Lost Wages, NV
Posts: 3,715
Quote:
Originally Posted by ShrekII View Post
Straight 6's are hard to beat...the old Dodge slant 6 was damn near indestructable..
Damn near? When I was in high school, a buddy of mine drove a 68 Barracuda with a 225 slant 6. He had a built 360 sitting in the garage just waiting to get dropped in but his dad put the nix on that until the slant 6 died. Us being the high school kids that we were decided to accelerate that. He brought the car into the auto-parts store that I worked at and we drained the oil out. His plan was to drive the car until the engine exploded. Two weeks later it was still running when his Dad found out about our little plan.
__________________
Quote:
Originally Posted by Hendrix
No one really knows the reason for LCOG Jeeps.

Its so short ****s like me and you can still get in.
Quote:
Originally Posted by 2ACR View Post
My issue was I couldn't get the balls centered. I had to use some extra force to get everything lined up right. It didn't take me long.


September 11 2001
Never Forget!
andy02 is offline   Reply With Quote Quick reply to this message
Unread 05-14-2012, 06:00 AM   #30
grandboost98
Registered User
1989 YJ Wrangler 
 
Join Date: Aug 2010
Location: Durham/East Haven, CT
Posts: 3,062
i picked up a 72 nova recently with a 250 i6 in it. i already planned on swapping a 350 into the nova and thought, what better place to put the 250i6 than in my jeep. that will be next years project
__________________
89 Jeep Wrangler - 3.5" HD BDS lift and M.O.R.E. HD 5/8" booms on 33s
99 Jeep Cherokee - 2 door, 5" lift on 33" super swampers
72 Chevy Nova - build in progress
98 Pontiac Grand Prix GTP - too many mods to list::SOLD::
grandboost98 is online now   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






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.