The timing belt rides off the CAM gear.

Tiny
DWP83445
  • MEMBER
  • 1998 CHEVROLET METRO
  • 182,000 MILES
I was given a 1998 Chevy Metro that the engine was bad in. I bought a used motor from a company and put it in the car (1.0 liter). It ran fine for about 10,000 miles and then the cam gear broke. I got a used cam gear from the company I bought the motor from and put it on the motor. When I put the timing belt on, it would not stay all the way on the cam gear, riding approximately 1/8 inch off. I was unable to find anyone who could tell me how to fix this. So I put it back together and drove it. The motor has approximately 5000 miles since I did this and the timing belt jumped a tooth. After taking it apart, it is obvious that the belt has been riding farther off the cam gear as the housing was full of fibers from the belt. Any ideas what could be causing this problem and what I do to fix it? Thank you.
Monday, February 13th, 2012 AT 2:05 AM

10 Replies

Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
Did you use a new belt?
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Monday, February 13th, 2012 AT 2:37 AM
Tiny
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Yes I did.
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Monday, February 13th, 2012 AT 2:51 AM
Tiny
FIXITMR
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Was cam gear exact match for 1 that broke?
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Monday, February 13th, 2012 AT 3:42 AM
Tiny
DWP83445
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From the piece I had left from the one that broke, yes it was. I called the company that I got the gear from and they said that it was from 1.0 liter so it should be the same. I tried putting a spacer behind the tensioner (found that suggestion on line) and that didn't make any difference. Asked all the mechanics that I know and no one had any suggestions so that is why I just put it together and drove it.
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Monday, February 13th, 2012 AT 4:02 AM
Tiny
FIXITMR
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Usually the crank gear has a flange washer to keep belt strate so it dont wander down there and this in turn keeps alignment with cam gear true. Maybe a defective belt or the tensioner got bent slightly in the mishap with cam gear?
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Monday, February 13th, 2012 AT 4:27 AM
Tiny
DWP83445
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I will check the tensioner. I put it all together and it is on the cam gear but as soon as I turn the motor over, it starts to come off. It seemed to ride about the 1/8 of an inch but obviously after I buttoned everythng up it started to walk off more. You can see on the plastic housing where the belt was rubbing and started to rub a hole it it. Thank you but I don't think it is the tensioner.
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Monday, February 13th, 2012 AT 4:39 AM
Tiny
FIXITMR
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Generally speaking, it would take 1 of the 2 gears to be out of parallel to make belt drift. If the original setup was fine, what happened? And why did cam gear break?
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Monday, February 13th, 2012 AT 6:07 AM
Tiny
FIXITMR
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Only things different are gear and belt.
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Wednesday, February 15th, 2012 AT 2:43 AM
Tiny
DWP83445
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Because I bought the motor from a company that gets them from Japan, I do not know what year the motor is for sure. There is a difference in belts between a couple of the years. I am getting one of each to see if that will make a difference. I have no clue why the gear broke. Like I said, no one that I have talked to has any idea what is going on, why the gear broke or why the belt doesn't ride properly. Hopefully the other belt will solve the problem. It is narrower but the same other than that.
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Wednesday, February 15th, 2012 AT 3:36 PM
Tiny
CJ MEDEVAC
  • MECHANIC
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WITH A DIAL INDICATOR, YOU MIGHT CHECK BOTH GEARS FOR "WOBBLE"

THIS IS JUST ONE SET-UP IN THIS VIDEO---THIS WILL SHOW YOU HOW IT WORKS, EVEN THOUGH THIS IS NOT WHAT YOU ARE TESTING

http://www.youtube.com/watch?v=H_1ySs7liS4

MY DIAL INDICATOR HAS RIGID BARS, A MAGNETIC BASE OR WILL CLAMP IN PLACE...MANY VARIATIONS (I REALLY LIKE THE ONE IN THE VIDEO! MAY GET ME ONE TOO!)

LET US KNOW HOW IT'S GOING, I KNOW YOU WANNA PIN IT DOWN BEFORE YOU START SPENDING $$$

THIS PROCEDURE MIGHT GIVE YOU AN IDEA AS TO WHICH GEAR--OR MAYBE EVEN A BENT SHAFT ETC.

THE MEDIC
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Wednesday, February 15th, 2012 AT 3:44 PM

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