: Timing question

05-06-11, 10:11 AM
I have a 2001 DTS and I am in the middle of doing the rear head gasket, in-car.

I am about to take off the timing chain and when I lined everything up I saw that the right intake cam is out of alignment by 2 or so degrees.

Now please don't yell at me for what I am about to say, but I was not in my right frame of mind when I did this. I was trying to get the crank bolt off with an electric 1/2 impact gun (works great on wheels) wasn't working. I didn't know it was on so tight. I tried a long breaker bar while holding the intake camshaft with a wrench. I know, I know this was stupid, I admit it.

Anyway, I stopped when I heard a couple of clicks. Now the sprocket is off a couple of degrees and the chain is loose on one side all the time. The timing marks on the crank are lined up OK, but the cam sprockets are not.

What did I break? Is the chain f*cked? The tensioner? Do I align everything and inspect the parts when I take off the chain and tensioners?

Thanks for the help,


05-06-11, 12:52 PM
i think it is the chain tensioner being loose now. they have a built in ratchet mechanism to keep them extended with no oil pressure. you can see the intermediate tensioner in your pic. reaching the cam tensioner will be fun.

05-06-11, 02:15 PM
Do you have the front valve cover off? If the timing marks on the front cams are still good, I would agree with stoveguyy. The rear chain tensioner should be easy to get to since you have the timing cover off. Look to see if it is retracted any more than the front cam chain tensioner.

Really, I would think the rear intake cam just slipped a tooth or so since you were trying to hold it still to get the crank bolt off. With everything still connected, everything would try to rotate when you applied torque to the bolt. Get the flywheel holder tool or wedge something through the flywheel teeth to stop everything from moving. You got the bolt off though, as evidenced by the missing pulley and oil pump...

05-06-11, 02:31 PM
Thanks guys, you made me feel better that it is probably just the chain tensioner.

Is this an interference engine? When I was rotating the crank over trying to get the timing marks aligned, it felt like there was compression even thought all the plugs are out.
What are the chances that the valves are hitting the pistons with the cam out of alignment by a couple of degrees?


05-06-11, 04:25 PM
yes it is interference. the valve springs provide lots of resistance as you turn motor over. i am not sure chain jumped any cam sprocket teeth. could all be due to slack in chain from relaxed tensioner.

05-07-11, 08:59 AM
Having the cam off a little will not cause contact I do not think.