ls timing chain

09-06-2011, 08:02 PM
I have a 2000 ls with a 3.9 and the secondary chain broke, if you put the flat spots on the cams all up does that mean that the cam timing is correct.

09-06-2011, 09:28 PM
From the factory service manual it sounds like the timing is aligned if the crankshaft keyway is in the 6 o'clock position and the flats of the cams are in the 12 o'clock position relative to the valve cover plane. If you send me a private message with your request and an e-mail address I can send you the procedure for the primary and secondary timing components. The text does not seem to match the diagrams completely.

From the factory service manual (some steps not pasted):

Turn the crankshaft to 45 degrees ATDC. The crankshaft keyway will be in the 6 o'clock position.
Make sure the lobes of the camshaft are facing upwards.

The text mentions "lobes" but in the diagram arrows are pointing to flat spots in the camshafts.


09-13-2011, 12:19 AM
If the secondary cam chain is broke, the valves are going to bend.
Once you get the timing right, do a compression check on each cylinder.
If 0 Psi = bent valves

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