03 lxi Coupe, 3.0, 89K, original owner, first time Newbie poster here looking for a little help.

While changing the timing belt/pulleys and water pump, during the install of the new belt, I had the rear cam jump as if it came off a lobe accompanied by a loud metallic clack like a valve slamming shut. I realigned the cam clockwise back to the timing mark and completed the install.

Pulled the engine through several rotations by hand with no audible noises, but at initial start, I now have a ticking coming from under the intake apparently from the rear bank. Otherwise, idles smooth, etc.

I removed the accy belts and covers again and rechecked all the timing marks. They are right on. I'm wondering if when the cam jumped, if I may of damaged a lash adjuster or worse.

Before I start pulling the intake and rear bank cover, I thought I ask if any of you have other ideas or suggestions?

Thanks in advance....

 

I forgot to add that when the cam jumped, it turned counter clockwise about 1/4 of a turn..

 

Ok.....WHY??? Did it break??? How much runtime is on the engine since the new belt went on??

It is possible that you bled out a lifter, and it will take a while to even itself out, It is also possible that if the belt was replaced for a failure, that you may have done damage ,prior to letting the Cam slip......

Truthfully, As for the cam slipping and damaging something....I suppose it could, but I severely DOUBT IT. Slamming shut is exactly what it does when its running.....And the spring tension is no different.....I would be more concerned about "OPENING IT" and forcing it againsst a raised piston, than Closing it against a Valvespring that was designed to do just that.

 

No, the belt did not break. This winter, on several cold mornings on initial startup, I was hearing loud bearing like noises until the engine came up to operating temps and it quieted down. Some old threads on this and a couple of other mitsu forums indicated similar problems when the water pump or tensioner pulleys were going. Considering I have 89K on it, I figured now would be a good time to do the water pump, belts and pulleys, before something broke. I had no ticking prior to the belt change.

Runtime since change has been 3 starts with idle runs of approximately 5 minutes each. 2 with accy belts on and one with them off. No change in ticking noise. I did not rev above the ecm controlled idle, but the tick does follow rpm.

Being an aircraft mechanic for 31 years, the lxi has had a regular maintenance program.. 3K oil/filters, plugs, pcv, etc. It has been rock solid reliable.

By lifter, are you referring to the hyd lash adjusters in the rocker arms? This is my first in depth maintenance on a sidewinder overhead cam engine, but I've had years of experience on mopar pushrod motors from the 225 super slant to the 383 big block. When I retired from the airlines, I parted with my 73 Cuda... at a profit, of course...

Thanks again for the reply and any additional thought/suggestions you might have.

 

After doing a little more online research, I found a Mitsu Service Manual for bleeding/pumping up the lash adjusters (lifters). In short, it states:

1. Allow engine to reach operating temp.
2. In 30 second intervals, smoothly advance rpms from idle to 3K in 15 seconds, then release and let idle for 15 seconds. Repeat for 10-30 cycles as needed.
3. If tick still present after 30 cycles, problem may be failed lifter or worn rocker. Troubleshoot as needed.

My 3.0 quieted down after each rev cycle and the tick was gone after 6 attempts.

Thanks for the assist.

 

Good information. I had the similar situation with my Harley with a cam chain tensioner repair. Scared me half to death when I first cranked it up. I just realized the Sebrings had timing belts. Somewhere I got the notion it had a chain. Now I'm in hurry up mode because I have 106 K relatively carefree miles so far on my 04 convertible.

 

If your '04 is a V-6, it has a timing chain, not a belt.