Cam Timing

[3.9-LS]

My passenger cam flats do not line up. Intake flat was pointing up at 12 oclock. Exhaust flat was pointing at 11 oclock. Chains an tensioners look good. Can I loosen the Exhaust cam gear and turn the cam with a wrench? Car is an 2001 V8 with 244k. I just bought it so I don't know it's history. It runs good but keeps throwing a lean code.

 

[3.9-LS]

bump

 

[1LoudLS]

cams don't just jump a tooth for no reason...

I would recheck the tensioners, there has to be a problem somewhere

 

[De-marko]

Possible the chain is pretty stretched out!

 

[Telco]

Stretched chain would be my guess too, and you're lucky it's just one tooth. Time to replace all the chains. You could replace just the one but I never saw the sense in replacing one chain and leaving the other two that had the same amount of wear as the one you are replacing for failing.

 

[pektel]

+1 on the chain. Inspect the links closely.

 

[3.9-LS]

Like I said, chains and tensioners looked good. I'm guessing they have been replaced sometime recently but the tech just didn't get the cams lined up. So... can I fix the cam timing? I'm NOT pulling the timing cover.

 

[pektel]

The chains/tensioner aren't "fine" if it's out of time. Do you know what a stretched timing chain looks like? Since you're guessing, I can only say that I have no more advice, as I can't see it from here. Good luck.

 

[chris2523]

it doesnt take much. replace the chains and tensioners.

 

[oddball]

Yes, you can just re-time the exhaust cam. I can't recommend it as the best practice, though.

Just follow the final steps in the timing chain R&R procedure. The sprocket is just a friction fit against the cam due to the cam bolt. You need to lock the cams into alignment then use a special bar to tension the chain while tightening the sprocket bolt. At least that's the factory procedure. You can invent from there.

FWIW, the primary chains seldom cause problems. The secondaries are the issue.