4.0L Timing belt question - 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 Cherokee & Comanche Forums > XJ Cherokee Technical Forum > 4.0L Timing belt question

The ULTIMATE "Selectable" Locker System! BroughECGS Fall Sale - 10% Off EVERYTHING!!Gear Packages Available! Your # 1 Diff Shop is ROCKRIDGE 4

Reply
Unread 08-26-2003, 01:36 PM   #1
daveleau
Registered User
 
Join Date: Jul 2003
Posts: 84
4.0L Timing belt question

I have symptoms (I think) of a going timing belt. The engine seems to sound faster and higher pitched when starting and the idle has dropped a bit, which has not been the case in the past. IF the timing belt goes before I can get it replaced, will it destroy the engine? I had a Honda Civic when I was in college and the timing belt went. It belt rods and tore the engine up to the point where I had to get rid of the car. The same happened 3 months later with my replacement car (Toyota Celica), but the engine damage was not there.

So, is the 4.0L engine designed to be able to handle a timing belt failure without destroying other parts of the engine?

Thanks
Dave

__________________
'87 Jeep XJ 4.0L 4x4 3" lift 31x1050
First time 4x4 owner w/ a project vehicle (which happens to be an every day driver)
daveleau is offline   Reply With Quote
Unread 08-26-2003, 02:51 PM   #2
ChrisinVA
Registered User
 
Join Date: Jan 2002
Location: Manassas VA
Posts: 818
The 4.0 doesn't have a timing belt. It's not an overhead cam engine like you're used to. It just has a plain 'ol timing chain, at the bottom of the engine. They generally last the life of the engine.

I seriously doubt that would be your 'problem'. More than likely it's your idle air motor gummed up.
__________________
94 XJ, 4.0/AW4/8.25/242. 145k miles, bought it in march of '02. Rusty's towhook on front, Hidden Hitch out back with shackle. Rebuilt AW4 in January, '03. Kumho MT's on AR767.
ChrisinVA is offline   Reply With Quote
Unread 08-27-2003, 10:48 AM   #3
TampaXJ
Registered User
 
Join Date: May 2003
Location: Tampa, FL
Posts: 152
Im thinking your problem is something with intake. LIke an idle air controller or something to that nature....as far as the engine and serious damage only interference engines cause serious damage when the timing belts let loose...toyotas and hondas(non interference) generally do damage with the water pump goes and seizes the timing belt causing the car to overhead and things inside to warp due to extreme heat...
__________________
Space Canoe: Little of this, a little of that...
Pope Wagon: 360 powered XJ...

H2...half the legend, twice the cost....
TampaXJ is offline   Reply With Quote
Unread 08-27-2003, 11:49 AM   #4
FourthGenHatch
Registered User
 
Join Date: Aug 2003
Posts: 140
If the 4.0 isn't OHC than does that mean its a Pushrod engine?

So if that chain broke (if that is even possible?) I heard that on a pushrod engine the pushrods just break but they are easy to fix. Is that true? Do I have the right idea?
__________________
Adam Carolla: "The hands down number one choice of car for a stripper is the Jeep Wrangler."
Dr. Drew: "Ironic how a stripper would choose a topless vehicle."

Last edited by FourthGenHatch; 08-27-2003 at 12:02 PM..
FourthGenHatch is offline   Reply With Quote
Unread 08-27-2003, 01:52 PM   #5
TampaXJ
Registered User
 
Join Date: May 2003
Location: Tampa, FL
Posts: 152
no not really...ok with our engines if the timing chain goes, as long as you stop within a minute or so and shut the car off you'll be fine. now with a cam engine...what happens is the valves open and close, hence the term interference, sowhen the timing belt goes the valves dont get out of the way of the uprising pustons and presto your piston just crushed your still opened valves....
__________________
Space Canoe: Little of this, a little of that...
Pope Wagon: 360 powered XJ...

H2...half the legend, twice the cost....
TampaXJ is offline   Reply With Quote
Unread 08-27-2003, 03:23 PM   #6
JTruel
Registered User
2005 LJ Wrangler 
 
Join Date: Mar 2003
Location: Broken Arrow, OK
Posts: 412
Almost all engines are "interference" motors

whether it has a belt or a chain it all works the same. If the belt or gear or chain breaks or jumps (which DOES happen with a timing chain) You have the possibility of busting a few valves. Pushrods are not the weakest link in your engine.. look at a pushrod, most are a little over 5/16 in diameter.. now look at a valve stem.. about 1/8 give or take, which will bend first? You be the judge.
__________________
2000 XJ Classic
2005 LJ
JTruel is offline   Reply With Quote
Unread 08-27-2003, 07:26 PM   #7
ChrisinVA
Registered User
 
Join Date: Jan 2002
Location: Manassas VA
Posts: 818
Fourth, please don't worry about it. Probably just your idle motor.

And yes...it is a pushrod/overhead VALVE motor. It's a modified version of those inline sixes you see in mail jeeps/CJ's.
__________________
94 XJ, 4.0/AW4/8.25/242. 145k miles, bought it in march of '02. Rusty's towhook on front, Hidden Hitch out back with shackle. Rebuilt AW4 in January, '03. Kumho MT's on AR767.
ChrisinVA is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





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.