Help finding noise after timing belt slip.

[Lazzer408]

It's my first post. be nice. =)

I was given a '91 Grand Prix 3.4L with 105k miles that had a no start problem. The guy I got it from started by cutting off the cat... then the coils and module... then it sat in his garage collecting dust for three years because he couldn't figure it out. To start over and undue the mess that he made, I put the coils back on and it had plenty of spark. I drained the tank, threw in 5gal of 93oct, and it sounded like it was trying to fire but wouldn't start. I gave it a shot of carb clean in the intake and again nothing. I pulled the timing cover off and wa-la shreded belt. Aside from GM making a 1hr job a 4 hour job due to the fact they didn't pin the cam gears and put marks on them... ...I put on a new belt and she fired right up. Now I hear this clacking noise that clacks at the crankshaft's RPM as opposed to the cam's RPM. Best described as a clatter. Not a rod (knock) or lifter (tick) sound. When I slowly rev the engine to about 2000-2500rpm the cam tentioner pully starts slapping around like mad. at 2500+ the pully calms down but I still hear the clacking. I know it's an interference engine and it sounds like a piston banging away at a valve but the car idles smoothly with no missfiring and the sound seems like it's comming from the front (passenger's side) of the engine. I'm wondering if the chain would be slapping around but when I rotate the crank pully back and forth the cam belt drive pully moves immediately as if there's no play at all. If anyone knows a common failure that makes quite a racket after a shreded belt, please let me know where to look.

Thanks

[GPXSS]

word to the wise.. only rotate these engines clockwise.

[Lazzer408]

or what happens? Releasing the key to quickly from the start position before the engine starts could allow the compression stroke to turn the engine backwards slightly. Is there yet another issue with the engine that GM failed to design corectly? (laugh)

[MeMadMax]

Hmmm does it have hydraulic lifters??? if its been sittin awhile then they are probabley sticky??? if so try some seafoam in the crankcase. if not somethings bent lol I've worked on VW's with bent valves that run perfect but make noise....

[Carlspike]

I'm pretty sure 91-95 LQ1's were non interference, and the 96-97 might be. If you have bent valves you will be leaking compression, and more than likely have a dead cylinder. You can do a compression/leak down test to rule that out. How does the car run despite the noise?

[SappySE107]

How did you retime it? Yes, keyed would keep the newbies from messing it up but for those that have done it before, you can net yourself more power from a free cam timing change.

[GPXSS]

unlike the pushrod engines, the timing belt / chain are tensioned on the slack side. If you reverse-rotate the engine while the timing components are installed, you are putting alot of pressure onthe tensioning devices and could possibly mess them up.