All 6G74s are not created equal...

[normal_dave]

Also could be titled, "Don't postpone your timing belt service", or "Friends don't let strangers work on your Montero engines"

Well, before any of you get the uneasy feeling in the pit of your stomach, this story has a happy ending with the timing belt change living happily ever after, (at least for the next 60K)

So I did the timing belt job on the wife's 2003 Montero Sport Limited 3.5L (6G74) quite some time back. As most know it is an involved job. It was successful, and I took great care in setting the manual timing belt tensioner eccentric. Helpful online images and expert instruction showed that the eccentric on the '03 Sport would be set in a CCW direction with the two holes ending on the bottom of the eccentric bolt and roughly inline with the body of the hydraulic tensioner when properly set. The '03 has the hydraulic tensioner mounted at an angle pointing upwards maybe to 1:00 or so facing the engine. It will look something like this:

We all know the mind is a terrible thing, and I like to follow instructions. First time on my '02 Montero (not Sport) I open up my saved document and follow step by step, noting I didn't have to remove the power steering pump or the A/C compressor (how nice!). I already knew the Sport had the oil filter on the driver's side front, and the Montero had the oil filter on the passenger side front, (duh, this is a difference..."difference" being a key word). So when it comes time to set the manual timing belt tensioner eccentric, I remember the grave importance of setting it properly to avoid disaster, pull up my saved instructions from the last job, FOLLOWING them to the letter, and it just won't work out right.

As soon as you mechanical genius veterans stop laughing, you can consider reading further. About the time I'm ready to start throwing tools, this is after I've removed the eccentric twice, inspecting it vs. the old one, finding nothing wrong, I decide to take a break. A cool glass of sweet tea, a long overdue sandwich, and time away from the garage made the difference. (Is that a forest I suddenly see or is it still just trees?). I lookup and find another post regarding timing belt on a 2001 3.5L 6G74 and you have to set the eccentric in the opposite, CW direction! You have got to be kidding me! I have years of engine and transmission experience, and supposedly I'm smarter than a fifth grader hobbyist mechanic. If that's true, then how can I be so stupid? Read through the expert (correct) instructions and it set perfectly, two rotations of the engine by hand, (wait 5 minutes) check again, and the grenade pin in the new hydraulic tensioner leapt out of the hole right into my hand. Burma Shave! FWIW, the hydraulic tensioner on the Montero mounts roughly horizontal pointing at ~ 3:00, which changes the angle of impact of the manual tensioner into the belt

So to any of you who have seen me post the above picture, trying to be helpful in regards to timing belt changes, I apologize sincerely and will take my beating, if you were working on a 2001-2002 3.5L 6G74, because by now, I know what the rest of you already knew, that it should have looked like THIS!:

Now for the rest of the story...Somebody got paid good money to work on my truck before I got it. They replaced one front cam seal and didn't bother fixing the other one. They also managed to leave the passenger side cam set off nearly 3 teeth! Now the truck seemed to sound and run fine, but it did have a slightly different note than the wife's truck which I attributed to the exhaust system. Whoops. I feel very lucky. Truck runs great now, no more oil leaks, and no occasional check engine light, and while I can't explain it, no more occasional flashing orange CD light in the 4WD display after driving for 30 miles or so at highway speeds.

Here are the before pics:
passenger side at TDC

driver side at TDC

crank at TDC

The old belt, cracks, torn on the edge, can't hardly read the Mitsubishi numbers on it. Whew!


So the truck runs great now, don't delay the job, it's pretty easy compared to the sort of same engine on the Sport.

 

[Fergie]

So, to make sure I understand it, in your first "before" picture, or the passenger side bank, the timing mark is two teeth to the left of the cam gear mark, correct?

 

[normal_dave]

Yep. The v-notch in the valve cover is the mark, the timing gear mark is sort of washed out by the flash, but it is two "teeth" off. There is a little dent in the valve cover just above it which is not the correct mark.

 

[Fergie]

Yep. The v-notch in the valve cover is the mark, the timing gear mark is sort of washed out by the flash, but it is two "teeth" off. There is a little dent in the valve cover just above it which is not the correct mark.

Thanks!

Im chasing down what I perceive to be a low idle issue on my 2001, and it has been suggested that the timing may be off on the passenger bank. All the issue started when I had the timing belt done.

 

[jeep-N-montero]

Yikes, you are lucky.

 

[quailchaser]

Also, another tip from experience. I somehow tightened the tensioner too much, creating a whine in the belt. Before it was fixed, I managed to ruin a brand new pulley, water pump, tensioner, and timing belt. It was a very expensive lesson I hope no one else goes through. When you tighten it, 4lbs is not much. Make sure you have a wrench that accurately reads it. Also the shop that fixed my screw up says they make sure the hydraulic tensioner works at least a little when you pull the pin. If the pin can be put back in after you pull it, the belt may be too tight.

 

[PA_JERO]

Also, another tip from experience. I somehow tightened the tensioner too much, creating a whine in the belt. Before it was fixed, I managed to ruin a brand new pulley, water pump, tensioner, and timing belt. It was a very expensive lesson I hope no one else goes through. When you tighten it, 4lbs is not much. Make sure you have a wrench that accurately reads it. Also the shop that fixed my screw up says they make sure the hydraulic tensioner works at least a little when you pull the pin. If the pin can be put back in after you pull it, the belt may be too tight.

The pin should be able to be placed back through the tensioner after everything has sat for 5 minutes and the engine has been rotated a few times. If tension is set to tight, the swing arm the eccentric pulley bolts to would push the hydraulic tensioner piston all the back and the swing arm would rest up against the hydraulic tensioner body. Setting tension is the hardest part of this project, and don't take any short cuts. I've set and reset tension about a dozen times on one timing job just because I'm not happy until the results are pretty much perfect. Last thing you want is to have your engine wrapped out at 4k RPMS or more, and the belt lose proper tension from a bad job setting tension.