91' Grand Prix GTP( Time for the timing belt!! @#%#**!!)

[quinnchuck]

First , I Call the car the BLACK WIDOW when it needs help.My wife drives the car, I just fix it .The timing belt frayed on one side making a real mess! After cleaning all the belting off the gears,I noticed that both idler pullies were worn. The bearings are imbedded in the plastic pullies.Are they stupid or what.That was my problem, with 160,000km and yes it was changed at 110,000km . Not by me mind you , but the GM dealership where I had bought the car,ROOKIES.They say the pullies should be changed with the new belt ,why oh why didn't they do it then . Now after I replace the belt , pullies ,and maybe the tensioner pully, re-aline the timing marks on the DOHC gears & crank TDC #1 piston .Should a guy be concerned about damage to these kinds of heads & the pistons, or just put it together and JUST SAY AHHHH...? This car is equipt with a timming belt , and has a 3.4L double over head cams (dohc) 24valve v6

[89s10]

does this engine have a timing chain, or a timing belt? What size is the engine?

[protege]

**** dude, you should call your car "mechanic's nightmare". The 3.4l DOHC engine in your car is a pain. Especially for timing belts. I was an apprentice mechanic, and when I was in school the people in my class that i talked to hated that engine, alot of the garage's that they worked at would turn away business from cars that had that engine because its a nightmare to work on. They'd send the owner to a dealer for work.
Oh yeah, I'm pretty sure that you should probably change the pulleys whileyou're at it.

[Beefy's Bronco]

Protege, you are so eloquent.

[Rich Y.]

If I am not mistaken, the 3.4 DOHC is not a freewheeling motor. This means that if you put the timing belt on wrong, or the timing belt breaks, it will bend valves, break pistons. Not trying to scare you, but you may want to realy study up on this one before gettin elbow deep in it.
Rich

[protege]

Originally posted by Beefy's Bronco
Protege, you are so eloquent.
I didn't mean that to come off in a bad way, but sometimes I'm misunderstood.

[Beefy's Bronco]

Originally posted by protege
I didn't mean that to come off in a bad way, but sometimes I'm misunderstood.

Just having a little fun with ya brother.

[1fatcat]

The GM 3.4L DOHC engine is a NON interferance engine. If the belt breaks, the valves and pistons will be OK.

You tell your story as if the belt is only frayed and not broken. But it also sounds like you have already replaced the belt and idlers. Did you mark the old belt to the cam and crank sprockets before removing it and count the cogs on the new belt, mark the appropriate ones and line them back up with the sprocket marks?

If you loosened the cam sprockets, you will need a special tool kit that is used to hold the cams for correct timming, you will also need a detailed shop manual. Or take it to someone who has the equipment and manuals.

The cam sprockets on these engines do not have key ways, the center bolt holds the sprocket tight via a tappered fit. The timming procedure goes something like this...

1. Install new belt and idlers.

2. Loosen cam sprockets.

3. install cam holding tools on one bank (don't remember which one is first).

4. turn crank to TDC on #1 cylinder.

5. tighten cam sprocket bolts on one bank.

6. switch cam holding tools to the other bank.

7. turn crank 180 degrees.

8. tighten cam sprockets on the second bank.


It is one of the most confusing timming belt procedures I have ever seen. It can be done pretty easily if the belt didn't break and if you mark the old belt to the sprockets and transfer the marks to the new belt.

Turn the motor over by hand with the spark plugs out before attempting to start the engine. If the motor locks up, you have problems...It shouldn't though, because this is a non interferance engine.

Ever put an alternator in this car? It's almost as much fun as the timming belt!

Good luck man! Hope this helps.

[quinnchuck]

Thanks for the info guy's ,a person just needs a second opinion at least once n awile. The timming belt didn't break , but did go out of time from the belt pieces being compacked in the crank & cam pullies.Which through the cams out & the belt still tight.The belt was still half there.
I would still like a couple more professionial reaplies to my question . Thanks again . Oh ya I could still use duck tape.
I was thinking that if the #1 piston is at TDC & the 4 cam gears realined to there origional marks >< and the belt put in place without anything moving back out of time , then things should be A OK ? Should't it?