My 1991 Toyota Cressida (3000cc 7GME motor 149k mi.)was making noises last year. I discovered the harmonic balancer’s keyway was sheared. A rebuilt balancer was installed and all was well for 3-4k. Now, it has happened again (by the sound and poor running condition). What could be causing the balancer to destroy itself? Thanks for any input, DMM
No comment on why your harmonic balance keeps coming off, but be careful. Running an engine without a harmonic balance can lead to your crankshaft breaking in half - either while the harmonic balance is off or even after you install a new harmonic balance.
My guess is the crankshaft was not properly hardened plus slack in the timing belt hammers the timing cog on the crankshaft badly. Replacing the pulley only corrects half the damage. A crankshaft is likely in order. I seem to recall posting a reply on that issue some months ago…
OK! Thanks to both of you! You have given me an idea. In this case, the crankshaft end looks ok, it’s the inside keyway on the balancer that disintegrates. A half moon key goes in this to secure the balancer to the crankshaft. I had the timing belt replaced at a shop, just before the first episode of this situation. Perhaps in that repair an error was made? Timing belt not tensioned properly? DMM
This has NOTHING to do with the timing belt. Install the new one with red Locktite on the mating surfaces after thorough cleaning. Then hammer the securing bolt in with an impact wrench. That bolt must be TIGHT to prevent any movement in this joint. The key will NOT shear off if the bolt is TIGHT and the tapered joint secure…