Mitsubishi Repair: timing belt, mitsubishi mighty max, piston head

Question
Mr.Falcone: I have a 87 mitsubishi mighty max 2wd pickup 2.0L manual tran.. My problem is I was driving approx. 25 mph when all of a sudden a clunk sound came from under the hood,the truck still was running but seem to lose some power and when ever I stepped on the gas and ran the rpm's up I would here a loud grinding noise.Do you think its the timing belt? And if that is true what is the grinding noises I here? And one last question is the bolt on harmonic balancer reverse threads? I have ordered a book on this truck, but it won't get here for another week.Thanks Jerry  P.S. Do you think I might have bent some rods or something? THANKS AGAIN

Answer
Jerry,
If your timing belt was off, your car would barely run even at idle.  Your problem may be related to a camshaft.  A roller on your valvetrain may have broke and now that camshaft is gringing on the bad roller.  That may explain the initial thud and the subsequent grinding noise you're hearing.  I'm not positive of the threads on the bolt for the harmonic balancer, but I would say they are not reversed.  If you have a broken/bent rod or piston head, you'd probably hear a lot more noise than just a grinding at high RPMs.
Good luck!