bent valves and timing belt hell "97 Sport"
 

I have a 1997 montero sport 4WDwith a 3.0L and around 10:30PM New years eve on the highway i was taking home a co-worker and all the sudden my engine starts running like hell and i see my engine temp on the H. I thought it was as simple as a blown radiator hose, oh if only. My dad ended up towing mehome in his SUV in the fog for about 3 miles on the highway and about 10 miles on the street to get back to the house.As it turned out my water pump i just repalced a year ago as "PREVENTITIVE MAINTAINENCE" seized up, while the timing belt still spinning around it melted all over all of the pulleys. In the process every intake valve was badly bent.I am a a fairly experienced mechanic so i've decided to save my self a couple thousand and do the valve job myself. I am currently $1200 into this project on parts alone i'm finally puting the thing back together right now i'm just waiting for new(automatic valve lash adjuster) orlifters or followers, whatever you wanna call thembecause all of the intake side lifters got jammed all the way inand wont come back out. I've only just discover what caused the whole damn mess. While going through the mitchell manual for my car i found that your are not supposed to let the timing belt cam tensioner pulleyrotate when you tighten it.the last time i did the timing belt i assumed the tensioner had to rotate while tightening to ensure no freeplay in the belt. Sounds like bad engineering toput the tensioner pulley on a cam if its not supposed to rotate. So the over tightened belt eventually burned out the waterpump bearing.

Just thought i would sharethat becauseI've never been so pissed and as a word of caution to anyone doing a timing belt.By the way when i took the heads off i saw how zero clearence these engines are. at TDC there is about 2mm of clearence between the intake valves and piston. So to anyone who jumps time, expect a valve job.

RE: bent valves and timing belt hell "97 Sport"
 

Wow, thanks for the post. I'm getting read to get real dirty with my 02 Montero Sport 3.0

I removed the driver side timing belt cover and found the cam sprocket off, just sitting in there. The bolt that holds it to the cam snapped..in short- **** broke!

I'm just trying to decide on trying to fix the engine or find a good used motor and do a swap.

What do you think?

RE: bent valves and timing belt hell "97 Sport"
 

The cam on the tensioner pulley is rotated with a special tool as a specified torqueto pretension the belt. Once the pretension is set, the center bolt is tightened to hold the cam from further rotation and hold the preset tension. At this point, the pin is removed from the hydraulic tensioner to maintain this preset tension. Same design on just about every Mitsubishi engine. Its too bad you missed that part esp since you took the initiative to do the extra preventative maintenance in the 1st place. Good luck to ya.

JJ

RE: bent valves and timing belt hell "97 Sport"
 

ahh, he was talking about the center "hub" section of the tensioner pulley not rotating, NOT the pulley itself. I was like "How you gonna make sure everything's set correctly when you spin the crank a couple rev's if the tensioner can't spin?"?

But yes, you have to have a small lever of some kind with two small pins to torque the tensioner pulley (I've always just done it on feel-- it doesn't take very much). Then you should be able to pull the "grenade" pin out of the automatic hydraulic tensioner, spin the crank a couple revs, and re-insert the pin. If it doesn't go back in, or come very close to going back in - try again with slightly moretorque.