How Hard Its It To Replace A Timing Chain?

[gogmorgo]

So I'm getting sick of feeding my 4.0 $70 in fuel every week, and was shopping around for an old beater econobox to try for some savings. Amid all the sub $500 listings for 4-cyl manuals, I spotted this: http://saskatoon.kijiji.ca/c-ViewAd?AdId=517423999

 

Any thoughts? I'm pretty busy, so I don't know how much time I'd have to put a new timing chain on it (if that's all it needs). I haven't looked at it yet, but I was thinking of offering $300 and going from there. Also not sure how much savings I'd be getting out of it...
 

[ComancheKid45]

I'm sure its not setup too much different than the 4.0s. The 4.0 is fairly straight forward but time consuming. Your looking at a solid afternoons worth of work but minus a Harmonic balancer puller the whole job can be done with basic hand tools ;)  

[johnj92131]

Sounds like you have a good plan.  Fix it and you save some money in fuel.  And you have a pot load of cheap spare parts for any future needs.  But don't forget to adjust your tire pressure and adjust your driving style.  Both of those things can gain more mpg on either a 2.5 or a 4.0, just should be even better with the 2.5

 

I would also be looking to see what I can do to bump the ignition advance forward for more mpg.  That used to be a good trick - just get a different vacuum advance in the distributor for more ignition advance at cruise conditions.

[carnuck]

If the timing chain actually broke, there will be more damage (bent valves for one) You have to count the links on the chain and gears to line them up plus make sure you get the kit with the tensioner. I did one before I broke my shoulder last year and it was a pita!

[carnuck]

Sounds like you have a good plan.  Fix it and you save some money in fuel.  And you have a pot load of cheap spare parts for any future needs.  But don't forget to adjust your tire pressure and adjust your driving style.  Both of those things can gain more mpg on either a 2.5 or a 4.0, just should be even better with the 2.5

 

I would also be looking to see what I can do to bump the ignition advance forward for more mpg.  That used to be a good trick - just get a different vacuum advance in the distributor for more ignition advance at cruise conditions.

That works for carbed rigs. The timing is controlled by the computer on the 4.0L and limited by the knock sensor which can mistake internal engine noise for ping.

[Rockfrog]

If you have time, look at it, pop the valve cover and rotate the motor ... if the valves move, it's probably not the chain. I've run into a number of "it's screwed" vehicles that were ridiculously simple fixes in reality. One was as simple as a set of plug wires put in the correct firing order (I can thank Haynes for that deal, printed a wrong firing order and saved me cash).

 

I've replaced the timing chain on my old 92YJ 2.5L a few years back, along with the oil pan gasket (only took a couple hours to do) ... if you have OK skills it's simple but time consuming job. Plan it for a full day, just to cover surprises ... pull the header and rad and there's loads of room to work.

[ComancheKid45]

If the timing chain actually broke, there will be more damage (bent valves for one) You have to count the links on the chain and gears to line them up plus make sure you get the kit with the tensioner. I did one before I broke my shoulder last year and it was a pita!

 

IIRC The 2.5 and 4.0 are non interference engines, so no internal damage would have occurred if the chain actually did break.

[mjeff87]

Here's a little writeup I did when I swapped mine (way back in 2007).  That engine is still running now with over 230K on it, in a different MJ.  Guess I did it correctly lol.

 

Jeff

 

http://comancheclub.com/topic/3094-how-to-timing-chain-replacement/?hl=timing+chain

[gogmorgo]

Mostly I'm wondering if there's anything I should be looking out for with this mj, and what I could expect for mpg. As of right now, I'm getting about 17 with my 4.0 and if it's not going to gain me much, then it's not really worth it to me.

[Keyav8r]

I don't see how you can pass this one up after taking a look at those seat covers!

[HOrnbrod]

 

If the timing chain actually broke, there will be more damage (bent valves for one) You have to count the links on the chain and gears to line them up plus make sure you get the kit with the tensioner. I did one before I broke my shoulder last year and it was a pita!

 

IIRC The 2.5 and 4.0 are non interference engines, so no internal damage would have occurred if the chain actually did break.

 

Except maybe to the timing chain cover. When one broke in my old stock 4.0 engine, it cracked the cover.

[JeepcoMJ]

All in all, timing is extremely easy on a 2.5 or 4.0. Buy a Haynes/Chilton's manual, it outlines the process. I could do one in my sleep.

[gogmorgo]

Yeah, the seat covers... I'm kinda wondering about how they relate to the er, larger gentleman on the tractor.

I didn't expect the timing chain to be too big of an issue.  I've never done one before, but I did read up on it. I'm just wondering what if any problem areas I should be looking at.

By the way, he turned down my offer for $300, sight unseen, which I kinda expected. But I'm trying to set up a time to see it.

[gogmorgo]

So it turns out the truck's a two hour drive away on his parents' farm, and he's willing to deliver it, but only if I pay the whole $500... apparently it hasn't run for about three years, either. Anyone out there think it's worth it?

[Eagle]

The 2.5L uses the same timing chain as the 4.0L, but the block height on the 2.5L is slightly lower so the 2.5L uses a timing chain tensioner inside the case to make up for the slack. You'll need to budget for replacing that as well as the chain itself. It's also possible that the chain isn't actually broken, that only the tensioner broke and is making noises.

 

However -- sight unseen, hasn't run for three years. I don't think it's worth $500 unless the body is in pristine (or nearly pristine) condition. Ultimately, though, it's really a question of what it's worth to you. Expect the gas mileage to be in the low to mod-20s.

[gogmorgo]

Well, just to provide some follow-up, I turned the guy down. Between school, my Formula SAE hobby and the work needed on my own MJ, I'm probably not going to have much time to get it running, and even then, I worked out that once I put plates on it, absolute best case scenario is that it won't pay for itself in fuel savings for over a year. Also, I just remembered that half the reason I was looking for another car in the first place was so I could have a back seat, and, um... yeah.

[Oyaji]

Well, just to provide some follow-up, I turned the guy down. Between school, my Formula SAE hobby and the work needed on my own MJ, I'm probably not going to have much time to get it running, and even then, I worked out that once I put plates on it, absolute best case scenario is that it won't pay for itself in fuel savings for over a year. Also, I just remembered that half the reason I was looking for another car in the first place was so I could have a back seat, and, um... yeah.

.

I  was a tech judge one year for Formula SAE. It was a good program; that year 113  universities from around the world sent teams. I am glad to hear it is still going on, good luck with your  entry. I am sure y'all are documenting your progress - maybe add a build thread here if you have the time? 

.

Yeah, for fuel savings, you need to aim a bit higher than an Iron Duke MJ - but good luck finding a vehicle to satisfy both economy concerns and a suitable back seat! :D.

[Eagle]

Yeah, for fuel savings, you need to aim a bit higher than an Iron Duke MJ - but good luck finding a vehicle to satisfy both economy concerns and a suitable back seat! :D.

 

Iron Duke!?!?

 

The Iron Duke was a Pontiac engine. BLASPHEMY! BURN THE NECROMANCER!

[Rockfrog]

the Iron Duke 2.5L 151cid was used in the CJ's ... it was replaced by the 150cid AMC 2.5L in 84, which was for all intents and purposes a 4.0 with the two center cyl removed (yeah, that's over simplifying it, but it's close enough).

 

In other words the IRON DUKE never saw duty in an XJ/MJ/YJ chassis.

[Oyaji]

To be honest, I had never heard the name except when going to the local Advance Auto Parts store and being asked every time, "Is that for the 4-liter 6, or the Iron Duke?". I have been using it with poetic licence for a few years. I  now stand corrected. *hangs head in shame*

.

Thanks for the clarification - it is a favor to point out an error, and I appreciate it. :)

 

[gogmorgo]

I  was a tech judge one year for Formula SAE. It was a good program; that year 113  universities from around the world sent teams. I am glad to hear it is still going on, good luck with your  entry. I am sure y'all are documenting your progress - maybe add a build thread here if you have the time? 

 

That's awesome. I'm guessing from the 113 number that'd be FSAE Michigan? I'm with the University of Saskatchewan team, Huskie Motorsports, and while I think the team's been to Michigan once or twice, we usually go to FSAE Lincoln (formerly California). Don't know if I'd be allowed by the team to post a build thread on here (we're incredibly careful about what gets published) but the build usually is fairly well documented on Facebook (https://www.facebook.com/huskiemotorsports) and we typically put up a video or two on the YouTubes (http://www.youtube.com/HuskieMotorsports) every now and again. There's a bunch of stuff from the last couple years on there, if you want to check it out. I've posted a couple of the videos in the pub section before, shortly after they came out, but didn't get too much interest. We've got a couple guys pretty well dedicated to getting our name out this year, so I'm expecting that the number and quality of videos is going to increase, but we'll see.

[Oyaji]

 

I  was a tech judge one year for Formula SAE. It was a good program; that year 113  universities from around the world sent teams. I am glad to hear it is still going on, good luck with your  entry. I am sure y'all are documenting your progress - maybe add a build thread here if you have the time? 

 

That's awesome. I'm guessing from the 113 number that'd be FSAE Michigan? I'm with the University of Saskatchewan team, Huskie Motorsports, and while I think the team's been to Michigan once or twice, we usually go to FSAE Lincoln (formerly California). Don't know if I'd be allowed by the team to post a build thread on here (we're incredibly careful about what gets published) but the build usually is fairly well documented on Facebook (https://www.facebook.com/huskiemotorsports) and we typically put up a video or two on the YouTubes (http://www.youtube.com/HuskieMotorsports) every now and again. There's a bunch of stuff from the last couple years on there, if you want to check it out. I've posted a couple of the videos in the pub section before, shortly after they came out, but didn't get too much interest. We've got a couple guys pretty well dedicated to getting our name out this year, so I'm expecting that the number and quality of videos is going to increase, but we'll see.

.

When I was involved there was only Formula SAE (competition took place outside Detroit at Auburn Hills), plus some sort of off-road competition as well (I don't recall the name of that one - "SAE Baja" sumpin'-or-other?). I am glad to hear the program ended up so popular that they added a second event. It's an awesome way  for students to get experience - they never fail to impress - and also to make contacts in the car business for job-hunting after graduation. I don't know if you realize it, but the  judging before   the  driving competition days  is  (or was  at Detroit, anyway) well-attended by managers who are  scouting for outstanding talent. (Out of the ~500 students in attendance, I saw 2 guys get offered jobs on the spot - there may well have been more I didn't see.) 

[gogmorgo]

Must have been a while ago, then! Actually, now that I look into it, FSAE West as it was called only started up in 2006, so not really all that long ago... But right now, there are 12 events around the world sanctioned by SAE international, 3 in the US, 6 in Europe, and one each in Brazil, Australia and Japan.

When I was down in Lincoln, a couple reps from Chrysler came out to talk to our graduating team members about jobs, but none of them were interested because they already had jobs. To be honest, I'm mostly just in this for the fun, but one of the other things that keeps me around is that no one ever in the history of our team has not had a job within the first couple months of graduating, and everyone's been able to get a decent summer job, too.