1G New timing belt disintegrating after fewer than 18000 km - WHY?

[sacrileger]

After installing a brand new timing belt and putting on about 18000km, i noticed the timing belt started making rhythmic 'swooshing' sounds as if the belt was flapping and rubbing against 'something' so i took the timing belt cover off to examine the belt and instantly noticed irregular shallow marks on the belt:

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the first thing i thought of wearing belt in such a way were bolts on the oil pan flange not being in their proper place, i.e.one or two bolts were too long and making contact with the belt. no such luck. i removed the two bolts right underneath the pulley and nothing changed. the swooshing sound continued.

continuing with my investigation, i noticed that some of the teeth on the timing belt, the opposite side of where the belt made contact with 'something', were partially broken off and some of them were in the process of breaking off; however, none of the teeth broke off completely... and what i meant by 'partially' is that only about 1/2 of the tooth was broken off:

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upon further investigation, i wondered if perhaps i put on the wrong timing belt cover as i wondered why is there a gap of about 1/2" between the oil pan flange and the plastic cover itself:

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this is a 1992 6-bolt 4g63 and the cover part number is MD141459 S / MD141461 B:

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Any thoughts as to what could have possibly caused this damage to the timing belt after only 18000 km?

 

[chrysler kid]

so far so good... i am checking the condition of the belt every couple weeks or so..

I think you already mentioned it, but I bet you had a piece of gravel get into the timing cover and wedge itself down by the oil pump sprocket before getting ejected with a vengence