Help! - Rocker Arm Stud Question

[CNCguy]

OK - so I want to check the cam timing.

First of all, the cam timing gear is indexed to the camshaft with a pin, the crankshaft's timing gear is indexed by the keyway. If the timing is in error, it will be because the timing marks didn't line up properly when the timing chain went on. I did check this when it was going together, but let's say I didn't do it right. I'd like to make this check without pulling the engine, if possible.

I can turn the crankshaft until I get the timing mark on the harmonic balancer lined up on the mark on the timing case. That will be TDC for cylinder 1 or cylinder 4 depending on which cycle of the crankshaft the camshaft is on.
One of the cylinders at TDC (let's say #1) is in between the compression stroke and work stroke. The other cylinder (#4) has just finished the exhaust stroke (exhaust valve just closed) and just starting the intake stroke (intake valve opening)

So if I turn the engine over until I'm just between exhaust valve closing and intake valve opening on #4, then where should I expect to find the timing mark on the harmonic balancer in relation to the mark on the timing case? Maybe a better way to ask the question is: how many degrees off TDC does the exhaust valve close and how many degrees off TDC will the intake open? I can turn the cam till the exhaust closes and measure against the timing marks.

Is the 3.1 (gen 3) an interference engine? If it isn't, should the valve ever be touching a piston even if the cam timing is off?

I don't have experience with a Grand Am but have pulled the TC cover off of other 60V6s with the engine still in.

I would not go by the marks on the dampner, there are marks on your timing gears that you align to get the timing correct. The marks should point towards each other as shown below. As long as the marks are correct, the timing should be right. Sometimes the crank gear mark can be hard to find but if you pay attention to the keyway location, it will give you an idea where to look for the mark.



It is an interference engine.

[ckrobins]

OK - I think that explains what's happening - I will pull the timing cover and have another look at the timing chain/gears. Thanks!

[ckrobins]

That was it - camshaft about 60 degrees off. timing chain and gears are in their proper places now and the engine is turning over freely. I looked again at the broken pushrods from the earlier mess and it turns out the were the correct length (the short ones broke)
Thank you everyone for your help

[CNCguy]

Good luck with it and let us know how it runs when you get it finished.

[ckrobins]

We finished putting it together on Saturday and she started on the second turn - purrs like a kitten. Sweetest sound in the world Thanks again to everybody for your help

[geoffinbc]

Well good to hear. I bet you will never make this mistake again after all the trouble you went through LOL.

[super40962]

The old studs are non adjustable, the replacement ones are adjustable. The will work you just need adjustable nuts.

[SappySE107]

Why are you replying to a thread that was dead in 2006?